prologue one reviews

ProLogue One Reviews

PrimaLuna

ProLogue OneINTEGRATED AMPLIFIER

y first reaction to the Prima Luna Prologue One was based solely on looks: For $1095, I might not have been disappointed had it sound-ed no better than a Bose Wave Radio. Its casework straddles the breach between vintage and modern in a way that little else does, at any price. The dark gray-blue finish, hand-rubbed to a tactile gloss,

wouldn’t look out of place on an Alfa GTV (the new one, which resembles a drop of oil). And for the first time in my experience, a high-end audio manufacturer has figured out a way to make a protective tube cage easy to remove and replace: with banana plugs and sockets. Why couldn’t one of the high-price American brands have figured that out? The theme continues inside, with point-to-point wiring that’s carefully dressed and neatly soldered. All the hardware is bolted in place, not just stuck to the inside of the chassis with glue and hope, and well-finished metal shielding is installed wherever hum or RF interference might otherwise intrude. All the tube sockets are good ceramic ones, and the terminal strips are ceramic, too. Thread-ed parts are locked in place with a dab of red enamel. All the edges have been smoothed over. Inspectors’ initials abound. Here’s where your music goes: Each channel’s preamp tube is a 12AX7A dual triode, the two halves of which are tied together in parallel in the interest of current gain. From there it goes to the two halves of a 12AU7 driver, configured as a long-tailed pair. Then it’s on to a push-pull pair of EL34s operating in “en-hanced” class-A/B, with screen grids tied to the output transformer’s primary so the tubes can deliver more power than if they were used in triode mode—yet also sound sweeter and exhibit a lower output impedance than if they were used in pure pentode mode. Tube-amp enthusiasts will recognize that as an Ultralinear output circuit, which the great David Hafler first described more than half a century ago. Sounds pretty simple, doesn’t it? It is—for the most part. Then again, be-cause the Prologue One is aimed at the first-time owner of a tube amp, Prima Luna wanted to ensure reliable performance in almost any setting, with no need for ad-justments. So chief designer Marcel Croese devised a new way to bias the output tubes. In a normal fixed-bias amplifier, the output tube’s cathodes are referenced directly to ground, and an independent negative voltage is applied to the signal grid: It’s that bias that the AC music signal modulates, continuously varying tube current as it travels from the cathode to the anode, and allowing the high-voltage output to mimic the low-voltage input. But because temperatures can vary inside a tube amp, and because tubes, like people, begin to deteriorate from the moment they enter the workforce, the bias will require periodic correction. The bias may also need to be altered in the face of unusually loud or bass-heavy signals, to pre-vent the higher voltage from functionally adding to the bias—and thus limiting tube current and compressing the output. Croese’s solution, called Adaptive Auto-Bias, is a circuit that continuously adjusts the bias voltage in response to changing temperatures and input signals. (Neither the J-FET op-amp at the heart of Croese’s circuit, nor its supporting parts, is in the signal path. Adaptive AutoBias, which is

Art Dudley

Description: Single-box line-level tube preamplifier and push-pull tube power amplifier. Tube complement: two each 12AX7A, 12AU7, EL34. Inputs: 4 single-ended. Output power: 35Wpc into 8 ohms (15.4dBW). Voltage gain: 20dB. Output impedance: 4 or 8 ohms. Frequency response: 20Hz–30kHz, ±0.5dB. Input im-pedance: 100k ohms. Input sen-sitivity: 300mV.

Dimensions: 11.5” W by 7.7” H by 15” D. Weight: 36 lbs.

Serial number of unit re-viewed: 04031452.

Price: $1095. Approximate num-ber of dealers: 1 (sold direct).

US distributor: Upscale Audio, 2504 Spring Terrace, Upland, CA 91784. Tel: (909) 931-9686. Fax: (909) 985-6968. Web: www.upscaleaudio.com.

EQUIPMENT REPORT

the only major portion of the Prologue One that’s laid out on a printed-circuit board, uses a reference signal derived from the amplifier’s input.) The result, according to Croese, is an increase in both per-formance and reliability—two things that don’t always track one another in the minds of hard-core tube enthusi-asts. And by taking the enthusiast out of the adjustment loop, the Adaptive AutoBias circuit ensures something else: moderation. “The adjustments made are very slight,” Croese says, “within narrow margins, so that the tubes always operate in the parts of their range that are lowest in distor-tion.”

For its part, the Prologue One’s power supply is as traditional as they come: High-voltage AC from the pow-er transformer is straightened out by a smallish rectifier bridge, and the bumps

and valleys are smoothed by a pi fil-ter centered around a sturdy-looking choke. Additional secondary taps lead to a separate filtering circuit for the tube heaters. Again: All of this is contained in one of the nicest-looking enclosures I’ve seen in ages—one in which all the metal parts fit together, and the sheet

metal doesn’t flex under the weight of the trannies, and the feet hold the thing far enough off the shelf that the under-side doesn’t get too hot. It’s also, coin-cidentally, one of the nicest-smelling

amplifiers I’ve had in a long time—like wood smoke, which I find pleasant. Let’s see if John Atkinson notices that, too, when he performs his measurements. (Don’t worry: There were no signs of burning trannies—or burning anything else—inside the Prologue One.)

I ran the Prologue One at one-third power into 8 ohms from the 8 ohm tap for 60 minutes—not so much to thermally stress it, as I do with solid-state designs, but to make sure it was up to its working temperature. (I didn’t notice the pleasant smell, Art!) I performed a complete set of tests from both its 8 ohm and 4 ohm output transformer taps, but have described the results for both here only when relevant. The input impedance was usefully high, at 95k ohms at 20Hz and 1kHz, this dropping inconsequentially to 76k ohms at 20kHz. The amplifier preserved absolute po-larity—ie, was noninverting—from both sets of outputs. The voltage gain was a little hard to assess accurately, due to the presence of very-low-frequency noise, which caused the level reading to bounce a little. But it appeared that with the volume control set to its maximum, the gain from the 8 ohm tap into an 8 ohm load was 37.5dB; from the 4 ohm tap into 4 ohms, 36.3dB. Because the amplifier does not have preamp or tape outputs, I could not assess how much of this

gain comes from the preamp stage and how much from the power amplifier circuitry. The output impedance was very high, at 5.8 ohms from the 8 ohm tap and 3.1 ohms from the 4 ohm tap. (These figures were measured at 1kHz; the source imped-ance was a little higher at 20Hz, a little lower at 20kHz, but inconsequentially so.) These high source impedances guarantee maximum power delivery into matched loads: approximately 6 ohms in the case of the “8 ohm” output, 3 ohms in the case of the “4 ohm” output. However, the downside is that there is a very audible modification of the amplifier’s frequency response due to the manner in which the loudspeaker’s impedance varies with frequency. This is shown graphically by the top traces in figs.1 and 2, which were taken with the amplifier’s 8 and 4 ohm taps, respec-tively, driving Stereophile’s simulated loudspeaker load. The response modification is as high as ±2.5dB and ±1.6dB, and cannot be discounted when auditioning the amplifier.

MEASUREMENTS

Listening Although I enjoyed every day I spent with the Prologue One—my aston-ishment at the level of value it offers couldn’t be more genuine—you may want to keep in mind that my review-ing environment is almost a worst-case scenario: Quad electrostatics on the one hand, high-sensitivity Lowther horns on the other. I heard just enough evidence of uncontrolled

bass with the former, and shoutiness from an overpowered whizzer with the latter, that I couldn’t help imagining that most real-world installations, centered around a dynamic loudspeaker of me-dium to medium-high efficiency, would sound even better than my own. All right—let’s dispense with this product’s most notable shortcom-ing: Driving the Quad ESL-989s, the Prologue One had a very underdamped

bottom two octaves. The bass drum in the Prelude of Ives’ Symphony 4, per-formed by José Serebrier and the Lon-don Philharmonic (CD, BMG Classics 63316-2), was boomy, with an unreal-istically long decay. Likewise the elec-tric bass and the lowest-tuned floor tom on the Band’s “Smoke Signal,” from Cahoots (CD, Capitol 25391-2), which also sounded slow and rhythmically un-stirring as a result.

These two graphs also show that the Prologue One’s re-sponse into resistive loads is commendably flat across quite a wide bandwidth, particularly at low frequencies. At high frequencies, the rolloff didn’t depend on the load to any great extent, which can be common in designs using an output transformer, but did depend on the setting of the volume control. It varied from –1dB at 30kHz at the extreme volume-control positions to –1dB at 20kHz in the unity-gain position (8:00). The Prima Luna’s reproduction of a 10kHz squarewave (fig.3) shows some slowing of the waveform edges, as well as a faint hint of ringing. But not apparent in the graph, which was taken with a digital oscilloscope (footnote 1), is a very brief overshoot on each leading edge, which was visible with a 20MHz analog ‘scope. It is possible, therefore, that the Prologue One’s circuitry is not uncondi-tionally stable; but if so, the parasitic instability appears to be in the MHz region and is probably inconsequential. The Prima Luna’s channel separation was moder-ate, at better than 60dB below 2kHz, decreasing above that frequency at the usual 6dB/octave rate due to capacitive coupling between the channels. The separation at 20kHz was 47dB, which is merely adequate. Of perhaps more prac-tical concern was leak-age between adjacent pairs of inputs. Because the amplifier does not have a Mute button, I was using the input se-lector to switch to an unused input between tests. When I did so, however, I noticed that the oscilloscope was still showing some high-frequency activity. Inserting a short-ing plug into the unused input didn’t make any difference; the leakage response in both the shorted and open-circuit conditions is shown in fig.4. If you’re playing a CD with, say, a switched-on tuner plugged into the next pair of inputs, you’ll hear a quiet treble ghost of the tuner signal in the background. The solution is to turn unselected sources down (not off), but it’s rare to see this behavior these days. With the input shorted and the volume control set to its maxi-

mum, the Prologue One’s unweighted signal/noise ratio (ref. 1W into 8 ohms) was moderate, at 64.9dB. This increased to 75.9dB when A-weighted. As expected from a design using a pair of EL34 out-put tubes for each channel, the Prologue One’s maximum power is relatively modest. Fig.5 shows the percentage of THD+noise present in the amplifier’s output while its 8 ohm output transformer tap drives increasing power

levels into loads ranging from 2 to 16 ohms; fig.6 shows sim-ilar curves for the 4 ohm output tap. With the load matched

to the nominal output tap, the 1% points are 21W from the 8 ohm tap (13.2dBW), and 24W from the 4 ohm tap (10.8dBW). It could be argued that using our usual defini-tion of “clipping” as being 1% THD would be misleading, as

the amplifier is not actually in hard clip at that point, but is really suffering from waveform triangulation and compres-sion of the peaks. So, relaxing the definition to 3% THD, where actual clipping is visible on the oscilloscope screen, the 8 ohm tap gives out 42W into 8 ohms (16.2dBW) and 14W into 4 ohms (8.45dBW). The 4 ohm tap delivers 25W into 8 ohms (14dBW), 47W into 4 ohms (13.7dBW), and 17W into 2 ohms (6.3dBW). I plotted the manner in which the THD+noise percentage changes with frequency at 5V output, a level at which the distortion products emerge from the noise floor. Figs.7 and 8 show the behavior from the 8 and 4 ohm taps, respectively. Though it increases to moderately high levels at high and low frequencies—reflecting the relatively modestly sized out-put transformers—and into loads that are much lower than the nominal value of the transformer tap, the midband THD is quite respectable. In fact, when you take into account the

fact that the main distortion component is the subjectively benign second harmonic (fig.9), it is not surprising that the Prima Luna sounds more powerful than its measurements suggest.

Roxy Music’s “More Than This,” from Avalon (CD, Virgin 5 83871 2), never really took off. But with the same speakers, the Prologue One sounded consis-tently fine with smaller-scale music, and with music that didn’t require so much in the way of quick, taut bass reproduction. The amp was engaging on good solo-piano recordings, such as the XRCD reissue of Thelonious Monk’s Thelonious Himself (CD, Riverside/JVC VICJ-60170). The Prologue One didn’t smooth over the deliberateness of Monk’s style, but neither did it sound unduly mechani-cal, a common enough failing, in my

experience, with other pentode amps. It tracked the album’s continuously shift-ing moods, from the playful to the se-rious and everything in between: The

music got bigger when it had to, without strain, and Monk’s touch was never lost in the process. And while other amps may do certain things better—the purr and sheer scale of the low B-flat in the bluesy “Functional,” for example—I’ve never heard another comparatively inex-

pensive amplifier get the humanness of Monk’s piano sound this right. The Prologue One’s tonal bal-ance seemed correct in a general sense—

if anything, it was tilted somewhat to-ward the bottom end—and it reproduced instrumental and vocal timbres in a man-ner that was essentially neutral, but with a hint of pleasant warmth and thickness, especially throughout the midrange: It was without question a sweet-sounding

At low frequencies, the onset of saturation of the out-put transformer core adds odd-order harmonics to the

amplifier’s sonic signature (fig.10), but note that the 120Hz power-supply component is still 90dB down in this graph. Only when I measured the Prologue One’s high-frequency intermodulation at a power just below visible waveform clip-ping on the oscilloscope screen did the amplifier begin to run out of steam, with power-supply components joining the intermodulation spuriae (fig.11). Even so, the level of in-termodulation is not catastrophically bad, as it can be with some single-ended designs.Considering its $1k price, the nicely made Prima Luna Pro-logue One offers relatively respectable measured perfor-mance. No, it will not rival a competent solid-state design on the test bench, but neither does it do anything to be ashamed of. —John Atkinson

amp, but not one I considered un-pleasantly colored. When I took my attention away from the music and focused on the sound, I heard that Norman Blake’s voice was slightly chestier than usual on “Greycoat Sol-diers,” from Fields of November (LP, Flying Fish 70004), and his vintage Martin D-18 was one color swatch darker. But the amp made up for it with a nearly SET-like presence and spatial believability on voice and gui-tar alike, and an equally believable sense of the space between them. Conductors all focus on dif-ferent things in the same music, and so, I think, do fine audio components. The Prologue One was acceptably good at conveying the scale and dra-ma of orchestral music, and while it

didn’t pull subtle details from the mix as explicitly as I would have liked—as in the aforementioned Ives recording, which needs all the openness and clar-ity it can get—it was good enough that I could listen for hours at a stretch with-out frustration or boredom setting in. But this amp’s strongest suit with good orchestral recordings was its tendency to find the color, substance, and textures of the instrumental sounds. Even on discs not known for their warmth, such as the 1962 Starker-Dorati recording of Dvoák’s Cello Concerto (CD, Mercury 432 001-2), the Prologue One brought out the best in massed strings, preserv-ing well their rich texture and timbral complexity. Simply put, this amp let that record sound beautiful. The Prologue One brought

those same strengths to well-recorded folk and pop music, too. It did a fine job with Tony Rice’s guitar solo on the great Lester Flatt song “Why Don’t You Tell Me So,” from Cold on the Shoul-der (CD, Rounder CD 0183), sounding especially twangy and right when Tony ventured down to the lower strings. And Ronnie McCoury and David Grisman’s mandolins sounded real—and appro-priately distinct from one another—on their fairly recent recording of Bill Mon-roe’s “Roanoke,” on Bluegrass Mando-lin Extravaganza (CD, Acoustic Disc ACD-35). Another plus was the timbral and spatial realism of Del McCoury’s backing guitar. On the minus side, the Prologue One made that recording and others like it a bit draggy, rhythmically: It missed a lot of the bounce and

Analog sources: Linn LP12 turntable with Naim Armageddon power sup-ply, Naim Aro tonearm; Rega Planar 9 turntable; Supex 900 Super, Linn Aki-va, Lyra Helikon Mono cartridges; Au-dio Note AN-S2 step-up transformer.

Digital source: Sony SCD-777ES and dCS La Scala-Delius SACD/CD players.

Preamplifiers: Fi, DNM 3C Primus.

Power amplifiers: EAR 890, Lamm ML2.1s, First Watt F1.

Loudspeakers: Quad ESL-989, Lowther PM2A in modified Medallion horns.

Cables: Digital: various dCS. Interconnect: Audio Note AN-Vx, Nordost Valhalla, homemades. Speaker: Audio Note AN-SPx, Nordost Valhalla, homemades.

Accessories: Mana stands under turntables, digital components; Base base under EAR, First Watt amplifiers; Wally tools for phono setup.

—Art Dudley

Conclusions In fewer words: This chunky little tube amp sounded like a chunky little tube amp, for better and for worse. That it’s so easy to buy and to use may steer you further from worse and closer to better. Apart from its clever bias cir-cuit, there’s nothing new inside the Prologue One’s handsome chassis, technologically speaking. Economi-cally, however—or geopolitically, or however else you want to look at it—there’s a much bigger story: An amp this good can’t be made to sell for this little in America, Europe, Japan, or even Mexico. So the Prima Luna Prologue One, while designed in the Netherlands, is manufactured in the People’s Republic of China. It’s

casework is fabricated and finished in China. Its components are wired to-gether in China. And its original, Dutch-designed output trannies are wound in China—apparently quite well. (The Pro-

logue One may not be at the very cut-ting edge of tube design, but it wouldn’t sound this good if its output trannies were crap.) Let’s face it: China, when she’s not busy buying up US currency, is busy making things, and making them well. And just like the clothes on your back and the flag in your yard, China makes them for a lot less than we apparently can. You are free to make of that what you wish. I know how I feel about it. Be-cause my first full-time job paid $96 a week after taxes, and my first integrated amplifier, a Sansui AU101, cost about $150, I’ve never shaken the notion that one’s first very good amp should cost between one and two weeks’ pay. And while I recognize that most things have changed since then—hi-fi doesn’t mean the same thing to young people today

that it did in the 1970s, when sequester-ing oneself with a record player was a way of turning one’s back on all other media, most notably television—I can’t help but feel that affordable or relatively

affordable products are good for every-one: for dealers, for magazines, and even for people who make and sell music in the first place. Of course, I may whistle another tune if our economy tanks and I can’t even afford the Christmas-tree or-naments at Wal-Mart on December 26. But for now, boy oh boy, can I ever recommend this amp! It’s not the liveliest-sounding thing, and if that’s more important to you than such things as texture and color, you’ll be better off considering something else. But if you’re new to the world of tubes and you want to see what it’s all about—and you’re on a limited budget, and rolling your own is out of the question—then it’s hard to see how you can go wrong with the Prima Luna Prologue One. Lustily, heartily, and enthusiastically (if conditionally) recommended.

f they ever offer a Nobel prize for bringing affordable audio to the masses, I would be the first to nominate Upscale Audio’s Kevin Deal. If you’ve been following the audio press at all, you know how well received the Kevin-Deal-distributed Ah! Tjoeb CD player has

been. Like the Ah! Tjoeb, the $1195 ProLogue One integrated amp—a tubed design, no less—was co-designed by Marcel Croese (the former chief engineer at Goldmund), and is rated at 35 watts per channel. (There’s also a 40Wpc KT-88 version for $1445.) The ProLogue One features a 12AX7, 12AU7, and a pair of EL-34s per channel for a very simple circuit. The front panel has a volume control, green power LED, and an input selector switch with four inputs, all electrically the same. The rear panel features one set of speaker outputs with beefy WBT style terminals (4 and 8 ohm taps) and four sets of high-quality gold-plated RCA jacks. An IEC socket is provided so you can upgrade the power cord at your leisure. Internally, the ProLogue One features point-to-point wiring for everything but the company’s proprietary Adaptive Auto Bias board. A tube cage is supplied in case you have inquisitive pets or children, but the ProLogue looks much better without it. Automobiles are my other passion, and I must admit while I am a big style junkie the nerd portion of my personality really appreciates build-quality. The ProLogue One is built like a $3000 piece of gear; the dark metallic blue finish on this thing is just gorgeous. Getting it out of the box was like one of those toys that you keep opening only to find another layer inside. By the third layer I found the amp, complete with a set of cotton gloves to handle it without leaving fingerprints. I guarantee that you will freak out at how great this little amplifier looks—it has a finish like a new Aston Martin. And I don’t say that loosely; I just photographed a new Aston for a book project last week. Upscale’s clearly-written manual mentions that the ProLogue doesn’t need an extended time to break in. It also describes the Adaptive Auto Bias that makes biasing output tubes a thing of the past. This circuit monitors and adjusts bias instantly, and PrimaLuna claims it also eliminates the need for matched output tubes and also extends the life of the tubes. Curiosity got the better of me, so I installed a set of EL-34s that I know have different sonic characteristics. The difference in sound between the misfits and the factory tubes was almost nonexistent, but I did notice that the amplifier would play a bit cleaner at maximum volume with matched tubes.

click here for

Enough about how it looks and operates; how does it sound? Bitchin’, that’s how it sounds.Over the years I have owned, built, and tweaked quite a few amplifiers featuring EL-34 topology, all the way from the legendary Dynaco Stereo 70 to my last amplifier, a much-loved Conrad-Johnson MV-55. The ProLogue One is right up there with the best of this genre. Straight from the box it sounded great, but a little stiff. True to the manual, it did not take very long to break in and after about a week of casual listening at my desk, 95 percent of the magic began. It took about a month to get the last little bit of sound out of the amp, but I’m splitting hairs here. I spend most of my time in front of five computer monitors writing about digital imaging for a number of other publications, so I get a lot of time to listen to music. The small system at my desk consists of a pair of original ProAc Tablettes, an old Proceed PDT 2 transport, a really old PS Audio Digital Link that I have modded a bit, and my old Dynaco SCA-35 integrated amp that is pretty much stock. Very warm tube sound indeed but comfy during 14-hour stints at the keyboard. For this review, I swapped the Proceed/PS Audio for my Ah! Tjoeb CD player (with all the Upscale Audio upgrades) and swapped the Radio Shack speaker cables for a pair of WireWorld Equinox 5 cables (that cost almost as much as the amplifier). Later on in the listening session, I also hooked up my Rega P25/RB 700/Shure V15xMR along with my Bottlehead Seduction phono preamp to explore analog playback. In a small-to-medium room at reasonable levels this amplifier will reveal a lot of music. In classic EL-34 style the ProLogue throws a very wide and deep soundstage, and has a wonderful midrange without sounding gooey like a Stereo 70 or other vintage design. The ProLogue One is very neutral with little of its own “signature.” With the ProAcs, imaging was very defined and close-up, yet when I took it out to the big room and hooked up my Vandersteen 2Ces the sound became more laid-back—unfortunately this amp doesn’t have quite enough juice to crank the Vandersteens. To achieve higher volume levels, a speaker with 90db or better sensitivity would be your best bet. What I did notice on both sets of speakers is a distinct level at which the music stops cold. Back it off a notch and everything is fine. Go up and the music collapses, the magic is gone, compression sets in. Observe this one rule with the ProLogue One and all is well. But sheer volume is not what this amplifier is about. It’s about groovy, dimensional EL-34 sound. My daughter’s drum instructor always says, “It’s the sound in between the notes,” and that’s what the ProLogue One is about. Everything has a great sense of airiness about it, and is more faithful to the original than a thousand-dollar amplifier has a right to be. While the ProLogue One does a very respectable job of reproducing bass (remember, moderation) having good extension as well as detail, don’t expect to rock the house with it. One of my favorite jazz recordings is The Three [East Wind], featuring Joe Sample, Shelly Manne, and Ray Brown performing some traditional jazz standards, recorded direct-to-disc. Their version of “Satin Doll” has some great acoustic bass riffs that the ProLogue navigated with no problem. Highs are very smooth without being rolled off and the presentation is very relaxed, but the mids are where this amplifier really shines. Listening to “My God Called Me This Morning” on the Fairfield Four’s Standing in the Safety Zone [Warner] was like having a gospel group right there in front of my desk, with all five singers having their own distinct voice and placement. Everything I listened to that was complex texturally was very absorbing and spatially well defined. Whenever I audition a new component I have my twenty or thirty favorite tracks that really define how something sounds to me. With the ProLogue One I found myself just letting the whole record play and enjoying the sound, and I guess that is the highest compliment I can pay to this amplifier. I wanted to make sure I wasn’t missing out on anything so I did a little tube swapping. For what it’s worth, you can change the character slightly by switching the stock Electro Harmonix tubes, but doing so doesn’t make all that much difference. I also swapped the WireWorld speaker cables for my new favorite Home Depot 10-gauge cable. Here there was a bit more difference, with the HD wire a bit more grainy than the Equinox, but again, we are talking about using a $950 dollar set of speaker cables with an amplifier that only costs $1095. In the end, you can substitute some spendy NOS tubes and ultra zooty cables to get more sound out of the ProLogue One, but for $1095 I would just make it the cornerstone of a really musical three-to-four-thousand-dollar music system.

Go to www.nobel.no right now and nominate Kevin for that prize!

Power output: 35Wpc (4 or 8 ohms)Inputs: Four RCADimensions: 15" x 11.5" x 7.68"Weight: 36 lbs.

ASSOCIATED EQUIPMENTRega P25 turntable; Rega P700 pickup arm; Shure V15xMR cartridge; Bottlehead Seduction Phonostage; Ah! Toejb 4000 CD player with full complement of Upscale Audio mods; ProAc Tablette and Vandersteen 2ce loudspeakers; Wireworld Equinox 5 and Home Depot 10 gauge speaker cables, miscellaneous AudioQuest interconnects

DISTRIBUTOR INFORMATIONUPSCALE AUDIO2504 Spring TerraceUpland, California 91784(909) 931-9686www.upscaleaudio.comPrice: $1195

SPECIFICATIONS

Hi-FiNews

PrimaLunaProLogue One

integrated amplifierA Chinese-built budget valve amp from Dutch

debutant PrimaLuna wows our oft-curmudgeonly correspondent. How do they do it for the money?

PrimaLuna Prologue OnePRICE £799

SUPPLIER Pistol Music

CONTACT 0208 971 3909

WEBSITE www.hifi-notes.com

Although there is no detailed research to back up my guestimate, I'd hazard that, based on my limited attendance at hi-fi shows, at least 50 new audio brands appear every year. Ordinarily, seedling brands are at best curiosities with the shelf-life of a fruit fly - here today, gone tomorrow. Unless, that is, they have something in the way of a pedigree.

PrimaLuna, a new valve amp from Holland, is immediately hamstrung in my book because of its absurd name. That's Latin for 'First Moon', which strikes me as a particularly ludicrous moniker. But there have been worse, of course - 'Anodyne' was a pip - and the name will pale (geddit?) into insignificance when you see the product that wears it. It's distributed in the UK by Pistol Music, a new division of Absolute Sounds.

Readers may recall a Dutch brand of hot-rodded Marantz products called AH! Njoe Tjoeb (speaking of daft names...) that offered ridiculous value for money, truly superb performance for negligible outlay.

The new company, part of Dutch high-end distributor Durob Audio's empire, represents all-new tube-related products - as opposed to modified components - of which 'extremely good

quality and [and] extremely good price/quality ratio are the main features.'

Durob's Herman van den Dungen, the closest that audio has come to producing its own Keith Richards, has applied over 30 years of high-end experience to the PrimaLuna project. His track

record is impressive, having distributed extreme high-end components in the Benelux territories while playing an active role in the creation of Kiseki cartridges and tone-arms, Milltek cartridges, PinPoint cones and other accessories.

Herman's team of fellow high-end veterans includes Marcel Croese, who designed for Swiss

brand Goldmund, along with Dutch designers once involved with Sphinx. Croese co-designed PrimaLuna's custom-made transformers with 'one of the most experienced transformer designers in the USA.' Uniquely, PrimaLuna also includes as part of it’s design team a group of local high-end

dealers and consumers ‘who judge every step taken by the design group. Prototypes, in-between-products, final products are tested in the field before going into "real" production. Direct comparisons with other brands' competitive models of the same but certainly of much higher prices is an important part of the judgement.'

With apologies to various British and Italian geniuses, this amplifier has - to my ears - no equals at its retail price

www.hifinews.co.uk

Hi-FiNews

Auditionsvalve amplifier

So, before we even get into the product, you're going to wonder how a European brand, saddled with typically high EU operating costs, can offer bargain products. Simple. Like savvy brands of far greater size, PrimaLuna has turned to China.

According to Herman: 'The design-people teamed up with two Chinese companies to build the products as economically as possible, without forgetting our strict tolerances of quality. The companies were chosen after serious and intensive studies and visits to China. A very important factor for the final choice was the proven experience and excellence of these manufacturers in the past.'

Herman is adamant that the PrimaLuna amps must not be mistaken for the earliest valve amps that came flooding out of China. Reliability and build quality have improved logarithmically over the past decade, to the great distress of Western manufacturers not using Chinese manufacturing. Factor in the costs, and the results can border on the unbelievable, as you will see.

In unleashing this Sino-Dutch product on the West, Herman insisted that after-sales service would be a function of the fundamental electrical design. 'Distributors, dealers and consumers should not waste their time and energy in difficult repairs. A faulty tube should never damage a circuit. The maximum replacement in the field, by the owner is a tube or a fuse. If an owner wants to replace his tubes - as several audiophiles like to do - no re-adjustment of the bias should be necessary. That is why we designed our "sustained auto bias" servo circuit with plate-fuse protection.'

The ProLogue One, a 35W integrated stereo valve amplifier, is PrimaLuna's first product. No matter where you look, the 292 x 196 x 381mm (whd), 15kg ProLogue One oozes quality. If your only experience of Chinese-made valve amps were the early 1990s efforts that suggested that every day was the 4th of July, you're in for a treat. Starting at the front, the knobs for source select and volume have the feel of something with a price tag to match a decent 42in plasma screen, and they rotate concentrically. The black front panel is finished to perfection, the power-on LED fits its aperture snugly, the side-mounted power--on rocker switch has no free play. The rest of the case is enamelled in a dark sapphire colour, including the valve cage, which was a particular delight: instead of screw fitting, it snaps into place using... banana plugs! Beneath it, the four input and driver tubes are arrayed in front of the four output tubes. Behind them are the massive transformers.

PrimaLuna provides conservative specification, reminiscent of vintage glassware in some areas. The frequency response is 20Hz-30kHz ±0.5dB and the total harmonic distortion - how's this for honesty? - is quoted as 1% with a signal-to-noise

ratio of 89dB. Input impedance is 100k ohm and input sensitivity 300mV. So far, so conventional - almost retro, eh?

Which was the first response my fellow listeners uttered. As the amplifier arrived at the same time I was undertaking a survey of small speakers, there was plenty of traffic through the listening room. Audio veteran Jim Creed and watchmaker Peter Roberts - the latter being particularly impressed with the PrimaLuna's parts quality and controls - both likened the sound to classic Radfords and Dynacos. Which was as good a place to start, as we auditioned them through circa-mid-1980s 15 ohm Rogers LS3/5As. I also tried the PrimaLuna with Spendor's S35se and Blue Note A3s loudspeakers, with sources including the Marantz CD-12/DA-12 CD player and the SME 30 Mk 11 with Series V arm and

Koetsu Urushi cartridge into the EAR 324 phonostage, using Transparent wires throughout.

You can't escape the vintage feel - the EL34 has characteristics that firmly place it in the Golden Age of Analogue - but PrimaLuna's team has done its work. The sound is so clean and coherent that the overall effect is not that of a compact valve amplifier but of a rather more ambitious, high-end behemoth.

Probably the most striking manifestation of this was the size of the soundstage coupled with the sheer mass of the lower registers. Quite how a brace of EL34s per channel can kick so much booty is hard to fathom. It certainly sounds more, robust that the Dynaco Stereo 70, if slightly more aggressive, while possessing greater punch than the more refined and genteel Radford STA25.

Where it veers dramatically from vintage amplifiers is in its sonic hygiene: whether it's down to newness or circuitry, the ProLogue One is cleaner, more detailed and more precise than its elderly forebears, and it demonstrates greater extension and control at both ends of the frequency range.

Despite this undeniable whiff of modernity, it still retains a charming, romantic quality, not unlike Herman himself in full-on seduction mode. But, also like Herman, the amp has a temper, too, and it was able to deliver the attack and power of up-to-the-minute power rock without problems. It handled the power chords and blistering transients on Welcome Interstate Managers, the new masterpiece from Fountains of Wayne, with sufficient speed and control, while displaying the

same upper frequency grace and 'air' grace that it called upon when splaying out the voices in Alison Krauss's 'Down To The River To Pray'. The rhythm section on Howard Tate's Rediscovered benefited from its fluidity and bass control, while the textures of that still-peerless voice were unmistakeable. And this guy veers into falsetto even more frequently than Al Green. The PrimaLuna simply followed the vocal swings like an obedient servant.Which leads me to one of those once-every- five-years-or-so watershed moments. I have no alternative but to state that the PrimaLuna ProLogue One is now my 'affordable reference amplifier'. With apologies to various British and Italian geniuses, this amplifier has - to my ears- - no equals at its retail price of £799. Yes, that's right: seven hundred and ninety-nine pounds. It's

so shockingly good, and promises so much for the rest of the range that the UK importer, Absolute Sounds, has created a special division for this and other more cost-effective solutions.

I leave this review somewhat shaken and I don't know which is the more shocking: that so much is available for so small an outlay, that the Chinese are now capable of producing audio separates this desirable, or that, after 25 years, Absolute Sounds has something for sale that normal people can afford. We do, indeed, live in interesting times.Ken Kessler

www.hifinews.co.uk

Herman van den Dungen, the closest that audio has come to producing its own Keith Richards, has applied over 30 years of high-end experience to PrimaLuna

TechnologyPrimaLuna's first product is the ProLogue One, an integrated stereo valve amplifier delivering 35W/ch from four El34s (two per channel’. lts front-end employs two 12AX7s and two 12AU7s, the design featuring automatic biasing and protection circuitry. It offers four line inputs served by gold-plated sockets, but has no line outputs, so recordists are not going to be too happy. Speakers are connected through lavish multi-way terminals with separate posts for 4 and 8 ohms.

Features

Push-pull design using EL34 valves

Four line-level inputs

Outstanding at the price

PRIMALUNA PROLOGUE: ONE INTEGRATED AMPLIFIER

Flavio Adami

Sometimes I ask myself, "Are today's solid-state amps, after so much evolution, aiming to achieve the sound quality of tubes, or is it the other way around? Is the latest generation of tube amps sounding like the new solid state tube amps?" One thing is painfully obvious with tube amps: they have a warm and full mid-frequency range that is easy to listen to. Missing, however, is the "punch" that characterizes solid-state amps, especially in the lowest of bass notes. There are powerful tube amps that can achieve this "punch" at exorbitant prices. Within a modest price range, however, tube amps generally have less power, extended low frequencies and slam. Once in a while I am surprised by something sent to my house that startles me immediately in terms of audio quality. The case of the PrimaLuna ProLogue One is one example. I have listened to many a solid state amp in my years that did make an excellent impression in terms of audio quality in the mid-frequency range-with the strength in the lower frequencies that is so common with solid-state amps. However the PrimaLuna sounded rather different in some aspects which will be explained. Construction is simple, compact, and robust while weighing 16 kilograms. The finish is in black sapphire, with just two knobs in front: one for volume setting and the other for the selection of the four line inputs. Curiously, the

on/off button is located laterally on the left side, and it took me some time to find it. Power is rated at 35 watts per channel using the well-known EL34, which passionate audiophiles have come to love for their sweet and musical sonority. It is built by hand with point-to-point soldering which means it uses no printed circuit boards. Its first-rate construction uses first-rate components with a toroidal transformer for the power supply and low noise encapsulated

transformers with wide frequency band for extended low and high frequencies. These transformers were developed by Marcel Croese, one of the most renowned audio designers, together with a "known" American transformer-designer. Ventilated ceramic sockets were used for the tubes, and an Alps potentiometer for the volume. Nichicon and Real Caps capacitors and gold-plated binding posts of the WBT type and RCA terminals were used.

The Adaptive Auto Bias system is exclusive to PrimaLuna. This circuit adjusts continuously and instantaneously monitors bias, and reduces distortion by about 40 to 50 percent. This means this amplifier will never need bias adjustment until tubes have to be replaced at the end of their lives. The PrimaLuna was set to 220 volts and even though it could be modified internally to operate on 110 volts, I decided to use a By Knirsch 2KVA transformer. Fortunately that did not affect the sound quality or cause any extraneous noise that could harm the results of this review. After careful installation in my system, I waited a few minutes for the amp to warm up and was immediately surprised at the absence of residual noise, even when I put my ears close to the tweeter of the speakers. I couldn't hear anything at all. That is exceptional especially in the case of a tube amp. In terms of music making, what immediately caught my attention was its harmonious sound reproduction, showing great equilibrium throughout the whole audible frequency spectrum, from the lowest bass to the highest treble notes. Even though it has some characteristics of a modern solid-state amplifier, its sound reproduction did not lose that famous tube magic. Low frequencies sounded different when compared to my solid-state amp: less "dry," more "rounded up," and less "dampened," in other words

"looser" but without exaggeration or loss of equilibrium. My speakers are 90dB efficient, and the PrimaLuna played them with great ease in spite of its 35 watts per channel, as long as I didn't turn the volume up too much. Otherwise the sound would harden, a common feature in a low power amp. In spite of the small dimensions of my room, I would say that the sound stage projected by the PrimaLuna exceeded its dimensions, with exceptional depth and width.Transparency was another important factor with a clear absence of "electronic effects,"especially with voices, both feminine and masculine, reproduced with a natural character.This unit does not have a full and congested mid range like many other tube amps. Rather it always sounded rich and natural with uncommonly natural timbres. When listening to more agitated music with instruments like the electric guitar, you might

loose some of the noise of the chords being plucked. In this case

solid state amps respond quicker, but on the other hand the harmonic richness of instruments like the piano, acoustic guitar, violin and cello was superior to many solid state amps with four times the power. The warm tone of the

woodwinds drove me to a high level of listening satisfaction; one which you only attain when listening to very expensive equipment- which is not the case with PrimaLuna. Conclusion Considering the cost/benefit ratio, every watt in the PrimaLuna in spite of the low power rating is a pleasure. This is reflected naturally in the joy and vivacity with which music is reproduced. Even at low frequencies, the "Achilles' heel" of many low power tube amps, it showed an uncommon extension and articulation using the traditional EL 34 as output tubes. I believe all this magic derives from a well-executed and intelligent design, with first-rate components, and output transformers of the highest level. As long as it is connected to efficient speakers, one obtains a surprising result since the

PrimaLuna knows how to balance out the magic of tubes in the mid-frequency region while at the same time maintaining extended bass and a "crystal clear" top end.

PRIMALUNA

Total Equilibrium 8.5Sound Stage 9.0Texture 8.5Dynamics 7.5Transients 8.0Harmonic Body 8.0Character 8.0Musicality 8.5

Total 66.0

Maximum points for equipment in the Gold category: 72

GOLD

RECOMMENDED

Distributor: Sound Stage (61) 225 3229

Average Price; US$ 2,200.00

:sons

C A tube amplifier was until not long ago(and still is, up to a point) a symbol of socialstatus. Tubes were once rare objects on theverge of extinction, just like panthers thatwealthy people show off as pets.

Whenever there’s a technological revolu-tion, there’s also some social resistance; the-re isalwayssomeone that saysno. That’showmyths and cults originate in some restrictedcirclesof society. Lookatwhat ishappening toLP. Thus the past ironically ends up by pro-gressively becoming fashion again.

Tubes were saved from utter extinction byits faithful supporters, who strove to keepthe flame alive by sharing experiences andprojects, often built by themselves at home,and also due to the end of Cold War, the fallof the Berlin Wall and the opening of Chine-se economy to the West.

In the West transistors had long replacedthe thermionic tube in audio circuits. The so-viet armament industry considered, however,that the latter was more trustworthy in extre-me situations, namely in the presence of ato-mic radiation. The infamous MIGs, for exam-ple, used tubes in some on-board transmis-sion equipment. When the soviet empirecollapsed, some western audio equipmentmanufacturers started importing tubes fromRussia (Sovtek, etc), Yugoslavia (Svetlana, etc)and China (cheap copies of the famous GE).What was once scarce was now abundant.

However, not even that was enough tolower the price of tube amplifiers. These are“hand-soldered” products made by true arti-sans (therefore, hard toproduce inautomatedassembly lines) andneedheavy transformersto lower thehighoutput impedance (exceptingthe OTLs).

Themythological statusandtheallegedsu-periority of the musical reproduction are not,hélàs,consentaneouswithpopularprices.ThefamousAudioNoteOngakuusessilverstrands

PRIMALUNA PROLOGUE ONE. By audiophilepatterns, thebuildingquality/price ratioof thePrologueOne isastonishing.NotevenDIYkitsthat you build at home on the kitchen tablecomeanycheaper.Moreover,unlike these, thePrologue One finish is anything but amateu-rish: materials, including the metallic lacquerof an ambiguous greenish black, are superiorto the competition even when products costas much as three times more. The design issimple and with no “kitsch” influences: theprotective grille, most certainly inspired byDarth Vader’s helmet, and the stylish cover ofthe transformers, all contributing to a percei-vedvalue that contradicts the realprice:1190euros. The golden plugs and the plastic-pro-tected terminals are state-of-the-art. This opi-nion is extended to the operation: no switch-on thump, clicks, pops or other commutationnoisesandwithanALPSpotentiometer that issmoothandefficient. Thiswasmadepossibleonly because its creator, a Dutch named Her-manvanderDungen,has themcustom-madein China to his specifications. The circuit hasno innovative topology: it is a classical push-pull amplifier with EL34 tubes (the PrologueTwousesKT88) that, at their limit, deliver40W(8 Ohm) or 36W (4 Ohm). Tube amplifiers arelike diesel engines - their ‘watts’ have more“horsepower”...

During the audition the Prologue One re-vealed its genetic origin and influence of theEL34 chromosome: a “romantic” sound, typi-cal of the 70’s, textured, expansive, with around and emphatic bass, a treble that liqui-fies as it warms up, and a mid-range thatseems to pour hot chocolate over the music.Voices have presence and “humanity” utterlyjustifying recurrent criticism in audiophilecircles that, by comparison, transistors sound“mechanical”. ThePrologueOneadds to thisasubjective sensation of power in the upper-bass that gives it anuncannysenseof rhythm.

WHENTHESUNRISES...PRIMALUNA IS A SMALL DUTCH COMPANYTHAT MADE HIGH-END POPULAR. BYPRODUCING THE INTEGRATED AMPLIFIERPROLOGUE ONE, IT PUT THE SOUND OFTUBES WITHIN (ALMOST) EVERYONE’SREACH.

José Victor Henriqueswww.hificlube.net

for the transformer windings and cost tens ofthousandsofeuros.AndtheWavacSH-833reachthe obscene amount of 300 000 euros!

Full, luxurious, exquisite, resplendent, invol-ving, fluid, transparent, “human”, these are justsome of the classical attributes of tube sound,something that backbiters assure to be no morethan the “hypnotic” effect oncredulousmindsofthe warmth of light combined with second har-monic distortion. Is it just a matter of faith then?

Ask thatquestion tosomeof themost famousguitarplayerswhodon’tdowithout their tubeam-plifiers. They will tell you that, besides the uniquetonalityof thesound, tubeshavemuchbetterhea-droom. This means they distort with class…

And yet, the alleged superiority of tube soundhas extensive technical support, namely: elec-trons are better transmitted in a vacuum (or gas)than in a solid state chip; resistance to overloadand the harmonic integrity, as it happens withsome musical instruments (the great cathedralorgans, forexample); buffereffectof the transfor-mers thatprotects theoutputstage fromnoise in-duced by the power supply; or, contrary to techni-cal common sense, even the high output impe-dance and consequent low damping factor whilestealing some of the tension confers harmonic ri-chness to the bass lines - Nelson Pass dixit.

In audio, as in life, one learns by making mis-takes. Parental advice to children is of no use.One can only learn from experience, hence onehas to listen foroneself. Anypieceofadviceor cri-ticism here is only useful as a guide line to yourown audition.

When I tested the Prologue One I hadalreadyread some of the opinions published by other in-ternational critics. The truth is that with more orlesseuphemism,moreor lessenthusiasm,moreor less technical and literary wit - and the inevita-bleholywater -,my“audition”wasnotmuchdiffe-rent from that of my distinguished colleagues: itis interestinghowobjectivitymayalso result froma set of coincident subjectivities.

DNm

.. 5de

Nove

mbro

de

2004

:60

To achieve the best results it is convenient tomatch it with proper speakers. I used a pair ofSonus Faber Concertino, which are easy to dri-ve and the Sony XA777es as a source. I prefer-red the4Ohmoutput,which “opensup”andgi-ves “bouquet” to thesoundby tradingoff somepower: a couple of watts are all it takes to fill asmall roomwithmusic though.Understressvoi-ces “harden” a little bit, robbing it of some of itsmidrange charisma. Thus, the more efficientthe speakers the better the final result.

Tubeamplifiersare like cigars: theymustbeenjoyed thoroughly, without too many expecta-tions, preferably in the company of good re-cords, good books and a good cognac. You canskip the fireplace in this case...

The sound of the Prologue One slowly getsinto you until it finally grows on you.

If this is the prologue (and the Prologue Twois even better) I can’t wait for the epilogue.

In Lisbon, the Prologue’s perform at Delmax,Rua da Madalena, 237, 1º Dt, (21 879 115)and, in Porto, the show takes place in Imacusti-ca, Rua Duque de Saldanha, 424 (22 537 7319). Go listen to them on a rainy day.

Translated by Ana Zenha from the original byJosé Victor Henriques.C C

equipment reviewer

28 | Australian Hi-Fi

It’s sometimes hard to love a valve amplifier. I find that this is usually entirely the fault of the manufacturer. Some are downright ugly, some are poorly built, some don’t have sufficient inputs, and a few are simply strange. So despite being an avowed fan of valve amps, it was with a little trepidation that I started unpacking the PrimaLuna ProLogue One. I needn’t have worried: it was love at first sight.

The EquipmentI say ‘love at first sight’ because you have only to see a ProLogue One to understand that it is superbly constructed: the evidence is right there in front of your eyes, five coats deep on a hand-polished heavy-gauge steel chassis. You can see your reflection in the paint. It’s so beautifully built that I thought it just had to be made in Italy, not least because when last I was in that amazing country, I passed through the town of Primaluna on my way to Lake Como, but mainly because the word itself is Italian (it means ‘First Moon.’)

Alas, it transpired that I was completely and utterly wrong, because PrimaLuna equipment hails from Holland. The brand name is owned by Durob Audio BV, a company owned by Herman van den Dungen, a Dutchman who has been distributing high-end audio components

in Holland for more than 30 years but recently started manufacturing his own equipment. During his time in the audio business, Dungen has obviously made a few crucial contacts, because working for him on the PrimaLuna range are none other than the famous Marcel Croese, (formerly with Goldmund) and Dominique Chenet (late of Jadis). They don’t actually build the amplifiers in Holland of course: that’s all done in China.

As you’d expect given Croese’s background, the ProLogue One is a very high-tech valve amplifier, with a soft-start circuit to enhance valve life, an auto-biasing system that ensures the valves run at optimum temperature for best performance and longest life and, because the bias is continually adjusted, you’re assured of the lowest possible distortion (and of course, there’s nothing for you to adjust!). All valves are fitted with plate fuses, so in the event of a failure of any kind, the most you stand to lose is a valve and a fuse. However, since PrimaLuna’s US distributor, Audio Excellence, says that in all the years he has been selling PrimaLuna he’s never had a single failure of either, the possibility seems remote.

Open up a ProLogue One (don’t try this at home, because you’ll void the warranty!) and you’ll find it’s mostly point-to-point wiring—all of which has to be done by

PrimaLunaProLogue One Integrated Amplifier

Power Output: Single channel driven into 8Ω, and 4Ω non-inductive loads at 20Hz, 1kHz and 20kHz, using 8Ω tap.

28-33 PrimaLuna HFNov06.indd 28 30/10/2006 1:49:15 PM

Australian Hi-Fi | 29

Brand: PrimaLunaModel: Prologue OneCategory: Integrated Valve AmplifierRRP: $2,495Warranty: One YearDistributor: Reference Audio Visual Pty LtdAddress: PO Box 171Park OrchardsVIC 3114T: 1800 133 135T: (03) 8813 0133F: (03) 9876 7283E: [email protected]: www.referenceav.com.au

PrimaLuna

Power Output: Both channels driven into 8Ω, and 4Ω non-inductive loads at 20Hz, 1kHz and 20kHz, using 8Ω tap.

hand, of course. There is a printed circuit board inside, but it’s for the auto-biasing. The inside of the amplifier is otherwise populated by high-quality components including metal film resistors, and Nichicon and Realcap capacitors. All tube sockets are ceramic, and the output transformers are completely encapsulated. The volume control is made by Alps. If you have ignored my sage advice and ill-advisedly popped the lid, you may be wondering about that JFET on the PCB. You needn’t. I have it on good authority that it’s part of the adaptive autobias system, all of which lies outside the signal path, and is fed from a signal sent forward from the amplifier’s input.

So far as I could establish, other than the soft-start and the autobiasing, the circuit follows a fairly standard ultralinear topology with the 12AX7A dual triode driving the two halves of the 12AU7, (configured as a long-tail pair), after which the signal ends up at the EL34 output valves, operating in push-pull with their screen grids linked to the output transformer primary. The auto-bias continually adjusts the bias voltage in response not only to the input signal, but also in response to temperature. The output transformer has two taps, one at 8Ω and the other at 4Ω. As in the olden golden days, the ‘negative’ terminal is not marked as such, but is instead marked 0Ω, which brought back a flood of memories. The speaker terminals appeared to be made by WBT, but did not carry that company’s initials. They are very high quality. They are also fixed on standard 12.7mm centres, so if you use the 4Ω tap you can connect your speakers using a dual Pomona plug. If you use the 8Ω tap, you’ll need individual bananas.

All four inputs are line-level and unbalanced, using RCA sockets. On the rear panel the inputs are (left to right): CD, Tuner, Aux 1 and Aux 2. At the far right of the rear panel is a standard IEC 240V socket with an integral fuse.

In Use and Listening SessionsI was a little surprised that my review sample came with all the valves already installed and, since the EL34s were wrapped in foam, I assume this is the standard method of delivery to consumers, and was not peculiar to my review sample. I was equally surprised to find that all eight valves were branded with PrimaLuna’s name. I assumed the valves were not matched, but I am not actually

sure of this. The manual notes that ‘While matched tubes are not a requirement, it is still recommended if you want to get the very best results. Better tubes sound better and matched better tubes sound even better than that! You can get the very best in replacement tubes as well as rare vintage NOS (New Old Stock) tubes from us and other parties if you wish to upgrade.’ Further on in the manual are listed various different valve types that can be substituted in the appropriate positions. The list contains the usual valves I would consider as likely candidates with the sole exception that PrimaLuna says the ProLogue One will work OK if you substitute the 12AX7s with 5751s. I didn’t try this, but on the face of it, it’s not a substitution I think I’d personally recommend. Indeed I would say you should use only exactly labelled 12AX7s from your preferred manufacturer. If you really want to experiment, go with old favourites like ECC83s or 7025s.

I am not a believer in leaving valve amplifiers on all the time. I cannot see the point in reducing the valve’s already limited life (though as I have mentioned in past reviews for Australian HI-FI, I would be surprised if you don’t upwards of 10,000 hours from small signal valves and more than 3,000 from power valves, so that’s a lot of listening) or, indeed, the point in hastening the effects of global warming which in this case would come about from the coal burned to provide the 240 volt power for the ProLogue One, and the heat given off by the valves themselves!

Because I think turning off power should be made as easy as possible, I was a little dispirited that the power switch has been mounted at the side of the amplifier, rather than on the front, where it’d be really easy to get to. I sat the amplifier on a specially-made table I recently acquired, so I didn’t personally find the switch at all hard to reach, but if I were still locating my equipment in the lowish equipment rack I used before I bought my table, my access to the power switch would have been quite restricted.

First up I connected PrimaLuna’s ProLogue One to another new arrival at my place, a pair of ProAc Response One SCs, which I had been encouraged to audition by one of my fellow reviewers at Australian HI-FI. [Editor’s Note: James Ross’s review of these ProAcs appeared in Australian HI-FI Volume 37 No 1.] I was impressed. The sound was everything I

love about valve amplifiers: sweet and warm, but with a transparency that allowed me to listen ‘through’ the music and a ‘liveness’ to the sound that removes it from the dull, stodgy ‘by-the-numbers’ reproduction of music that’s so evident on so many solid-state amplifiers. I find too many solid-state designs—and increasingly so these days, for reasons I have yet to fathom—remove the ‘life’ from the music. Sure the sound is accurate, free from distortion, and free from extraneous background noise, but without life, music is nothing. Music is supposed to live and breathe.

The PrimaLuna revealed one of its strongest points on Steve Hunter’s CD ‘Condition Human’, which features a different (female) vocalist on almost every track. I’d been enjoying this CD for several weeks, but it wasn’t until I hooked up both the ProAcs and the PrimaLuna (or ‘dad’s new Ps’, as my daughter—who’s at the age to appreciate scatological humour—would have it) that I really began to appreciate the different qualities of the voices, and how they worked in with the songs Hunter had selected, so the ProLogue One was obviously doing something very right! The combination also let the vocals ‘float’ clear of the backing instruments, yet at the same time project the complete image forward


TEST RESULTS


into the room. There’s a lot of reverb and effects on this CD, and the PrimaLuna worked its magic in this area as well, adding interesting complexity.

Switching over to my usual large floor-standing speakers, the PrimaLuna quickly revealed what turned out to be its Achilles’ heel, which is that it doesn’t exert a lot of control over the bass, most notably low percussion—kick drum and tympani, for example—so that rather than just a sharp ‘thwack’ sound, there’s a lengthier decay that meant that if a lot was going on at very low frequencies, the sound presented as being a little ‘dark’, though I didn’t hear any attendant low frequency confusion per se. This barely affected music that used only small forces (soloists and small ensembles, whether they were jazz, rock, or whatever…) but was noticeable—though not overly intrusive—with orchestral works.

I was pleasantly surprised to find the PrimaLuna ProLogue One worked its midrange magic when driving my floor-standers, with the vocals still sounding beautifully fluid and limpid and projected

Test ResultsNewport Test Laboratories measured power output at 39 watts per channel (15.9dBf) into 8Ω, both channels driven into 1kHz, which was just 4 watts (and 0.4dB) above PrimaLuna’s 35 watt rating. Measured power output increased to 43 watts (16.3dBf) into 8Ω when only a single channel was driven. Power output fell slightly at higher frequencies, with the extreme example of this being at 20kHz, where the lab recorded 32 watts output into 8Ω when both channels were driven and 36 watts into 8Ω with just a single channel driven. Power output sagged significantly at very low frequencies, with NTL recording a maximum output of 10-watts per channel into 8Ω, which remained the same irrespective of whether one or both channels were driven. As usual with valve amplifiers, maximum output was not measured at the onset of clipping, as it is with solid-state amplifiers, but when the output contained 3 per cent THD.

When measured whilst driving 4Ω non-inductive loads, the ProLogue One met its power specification only at 1kHz and only when a single channel was driven, with power output at this frequency falling to 32 watts (15.5dBf) when both channels were driven. At high frequencies, output was measured at 13 watts and 14 watts per channel (both-channels and single-channel driven respectively). Interestingly, output at low frequencies was higher with 4Ω loads than it was with 8Ω loads, as you can see from the tabulated figures and the bar graphs.

Frequency response was moderately extended, with –3dB points at 3Hz and 64kHz and, using non-inductive 8Ω dummy loads, it was also very flat across the audio band, measuring at 3Hz to 64kHz ±0.5dB. However, as you can see on the combined frequency response graph, the amplifier’s frequency response when driving a simulated speaker load (the red trace) was far from flat, swinging 2dB either side of reference. It was nearly 2dB high at 70Hz, 1.8kHz, and 18kHz and nearly 2dB low at 200Hz and 4.5kHz. What this means is that unless you are driving speakers that present a purely resistive load (such as a pair of Magneplanars, for example), the tonal balance of the PrimaLuna ProLogue One will be altered very perceptibly depending on the speakers that are connected to it.

The cause of this variation turned out to be the output impedance of the transformers, which was very high, coming in at 5.1Ω for the 8Ω tap (the 4Ω tap wasn’t tested). Presumably, the output transformer has been wound with such a high impedance in order to guarantee maximum power from the amplifier, but it also means a very low

Power Output: Single and both channels driven into 8Ω and 4Ω non-inductive loads at 20Hz, 1kHz and 20kHz using 8Ω tap.

Readers interested in a full technical appraisal of the performance of the PrimaLuna ProLogue One should continue on and read the LABORATORY REPORT published on the following pages. All readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be construed as applying only to the specific sample tested.R

EP

OR

TL

AB

forward into the room with plenty of surrounding air. When I re-listened to ‘Condition Human’ to check this, I thought James Muller’s guitar came though more smoothly, with a little more ambience, which worked well on this recording. Nick McBride’s cymbals also sounded sweeter than I think I’ve heard them previously, and with a bit more ‘ride’ and ‘zing’.

ConclusionPrimaLuna’s ProLogue One is a lovely-sounding amplifier, that in every way fulfils the promise of its appearance, not to mention its attractive-sounding name. Audition one with your preferred loudspeakers, or choose speakers specifically to partner it, in which case I’d suggest you bias your decision based heavily on their efficiency—89dB or higher would be optimum, in my view—and their design—bookshelf, electrostatics, planar magnetic or floor-standing speakers using bass drivers less than 30cm in diameter would be ideal—and your ears will quickly reveal the good news. Chris Croft

er er PrimaLuna ProLogue One Integrated Amplifier


TEST RESULTS


damping factor—in this case one of just 1.6—which in turn limits the amplifier’s ability to control unwanted cone movement. (Research by Floyd E. Toole in the 80s showed that damping factors of less than 30 can easily be perceived by trained listeners.)

Channel separation was adequate, with a maximum of 67.5dB at 1kHz, reducing to 60dB at 20Hz and 64dB at 20kHz. Separation between different inputs was measured at 68dB or more at 1kHz and below, but increased with increasing frequency, to around 53dB at 20kHz. Input separation is usually greater than 90dB. What this means is that when listening to the ProLogue One you should have only one input ‘active’ at any time. So if you’re listening to a CD player plugged into the CD input, for example, you should make sure the components plugged into the Tuner, Aux 1 and Aux 2 inputs are switched off. Channel balance was adequate, at 0.3dB, and inter-channel phase accuracy quite good for a valve amplifier, at just 1.6° in error at 20Hz and just 1.03° at 20kHz.

Distortion was relatively low at low power outputs, but increased rather spectacularly at higher power output levels. You can see from the spectrograms that at one watt out, the primary distortion components were the second and third harmonics. Into 8Ω, the 2nd harmonic sat at –60dB (0.11%) and the 3rd at –75dB (0.01%). These two components increased slightly when driving 4Ω loads, but the major difference between the two graphs is the marked increase in levels of the fourth and fifth harmonic distortion components. At rated output into 8Ω, harmonic distortion components are visible right across the audio spectrum, up to the 18th harmonic. The primary low-order components (which have the most effect on sound quality) hover around –50dB (0.3%), though the fifth almost reaches –40dB (1.0%).

The level and structure of the harmonic distortion components when the amplifier was driven into 4Ω was similar to what’s shown in the 8Ω spectrogram, but kicked in at much lower output powers. The spectrogram shows distortion across the audio spectrum when the amplifier is delivering 9 watts into 4Ω (using the 8Ω transformer tap). Despite all this, overall THD+N figures were respectable at 1kHz into 8Ω loads, coming in at 0.08% for one watt, increasing to 0.87% at rated output.

Intermodulation distortion was relatively low. The spectrogram shows the twin peaks of the 19kHz and 20kHz test signals at the far right of the graph. The (unwanted) sidebands to the left and right are around 65–68dB down. More importantly, the unwanted regenerated 1kHz signal (the difference



TEST RESULTS


PrimaLuna Prologue One

Test Measured Result Units/Comment

Frequency Response @ 1 watt 4.2Hz–30kHz –1dB

Frequency Response @ 1 watt 3.0Hz–64kHz –3dB

Channel Separation 60.9dB/67.5dB/63.8dB (20Hz/1kHz/20kHz)

Channel Balance 0.3dB @ 1kHz

Interchannel Phase 1.6/0.08/1.03 deg (20Hz/1k/20k)

THD+N 0.08% / 0.87% 1 watt/rated o/p

S/N Ratio (unweighted/weighted) 78.1dB/85.6dB dB re 1 watt output

S/N Ratio (unweighted/weighted) 94.1dB/100.1dB dB re rated output

Input Sensitivity (CD input) 35.5mV/215mV (1 watt/rated o/p)

Output Impedance 5.1Ω OC = 4.519V

Damping Factor 1.6 @ 1kHz

Power Consumption N/A/132 watts Standby/On

Power Consumption 138 watts /250 watts 1-watt/Rated op

Mains Voltage Variation 237–245 volts Min–Max

10kHz Square Wave (8Ω resistive load)

1kHz Square Wave (8Ω//2µF capacitive load)

PrimaLuna ProLogue One Integrated Amplifier - Power Output

Channel Load (Ω) 20Hz

(watts)

20Hz

(dBW)

1kHz

(watts)

1kHz

(dBW)

20kHz

(watts)

20kHz

(dBW)

1 8Ω 10** 10.0 43 16.3 36* 15.5

2 8Ω 10** 10.0 39 15.9 32* 15.5

1 4Ω 17** 12.3 36 15.5 14* 11.4

2 4Ω 16** 12.0 32 15.5 13* 11.1

1 2Ω NT NA NT NA NT NA

2 2Ω NT NA NT NA NT NA

Note: Figures in the dBW column represent the output level, in decibels, referred to one watt output. NT=Not Tested **=3%d

between 19kHz and 20kHz) over at the far left of the graph is down at –58dB (0.12%).

The PrimaLuna ProLogue One’s signal-to-noise ratio was satisfyingly high, with unweighted noise coming in at 78.1dB referred to one watt, increasing to 85.6dB with ‘A’ weighting. Referred to rated output, the signal-to-noise ratios were 94.1dB and 100.1dB respectively, so the amplifier will be quiet. The sensitivity of the CD input was standard, requiring just 35.5mV at the input to drive the amplifier to the 1-watt output level, and 215mV to drive it to rated output.

The square wave oscillograms show graphically most of what I have already described. The tilt on the top of the 100Hz square wave shows the amplifier’s limited low-frequency response, and the curvature on the top of the wave its low-frequency

100Hz Square Wave (8Ω resistive load)

1kHz Square Wave (8Ω resistive load)


phase shift. The 1kHz square wave is good, but far from being a replica of the input signal, shows some rise-time limitations, and what appears to be a rising frequency response (above the audio band). Loaded down with a 2µF capacitor, there was no ringing nor any output stage instability, so the amplifier would be well-suited to driving electrostatic loudspeakers. The wrinkled appearance of the leading edge of the 10kHz square wave appears to indicate some ringing at ultrasonic frequencies, which is obviously undesirable but apparently benign.

Mains power consumption was high, with the amplifier drawing 132 watts from the 240 V mains supply whenever it is switched on, increasing to 138 watts operating at the one-watt level, and to 250 watts when operating at full power. Steve Holding


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connect- Herald Sun, Wednesday, February 23, 2005 7

TH

EVER

DIC

T PrimaLuna Prologue One

Model: integrated valveamplifier

Price: $2499

Pros: High-end sound for abudget price, excellentstandard of finish, breezyset-up, clearly written manualand solid speaker terminals.

Cons: The modest powermeans it works best withspeakers that have a powerefficiency of 90db or better.

Sound investment: Sound &

Vision editor Peter Familariwith a McIntosh MC275.

Valvesrock on

VALVE amplifiers are along way from history’stechno scrap heap.

Hundreds of brands arebuilding amplifiers,preamplifiers and CD playersstudded with valves.

Just after getting thePrimaLuna to review, Connectreceived the new McIntoshMC275 amplifier, the AudioValve Eclipse preamplifier andBaldur valve monoblocamplifiers. There is also anintegrated amplifier fromPlessis Audio.

The big Mac, which will sellfor $5299, is not the GordonGow model released severalyears ago. It’s a new model thatsounds much more transparentthan the Gow edition.

Audio Valve is a German-made brand. It has styling andthe kind of performance thatdefines what we’ve come toexpect from valve technology.

The 75 watt a channel Monoblocs will have an RRP ofabout $10,000.

The sweet-sounding Plessiswas designed in Sydney andmade in China to a highstandard.

It has auto valve bias and canbe switched between triode andultra linear mode.

Each model will beroadtested in Connect soon.

PETER FAMILARI

Peter Familari

discovers an

amplifier making

loud noises in the

audio world

Hot glass,cool sound

THE hottest product to kickstartthe new audio year isn’t aleading-edge, high-price digi-

tal amplifier. It’s the budget-pricedPrimaLuna Prologue One, thanks toits amazing sound and exquisitebuild.

Connect international showreporter Ken Kessler was bowledover when he reviewed the PrimaLu-na Prologue One for Britain’s Hi-Fi

News and Record Review magazine.

As were writers for Americanaudio magazines Stereophile andThe Absolute Sound.

The reviews said the PrimaLunaset a benchmark at its price.

The PrimaLuna (right) has nowarrived in Australia courtesy ofVictorian-based distributor Refer-ence Audio Video.

A sample arrived at Connect’s

listening room, where it was quicklylinked to a pair of ProAc Response1SC speakers and Arcam’s 33T CDplayer, wired throughout with Shu-nyata interconnect, speaker cablesand a Hydra 2 power filter.

The sound came on song withoutan extended burn-in period.

But after a couple of weeks ofwork it went to a new level as thevalves and point-to-point circuitburnt in.

Veteran audiophiles such as mygood buddy Wolf felt the sound wasgood enough to embarrass a pair ofrevered Quad 11 amplifiers as wellas a much-adored Radford STAmk3amplifier I own.

With the Proacs, the PrimaLuna’ssound was clean and coherent fromtop to bottom and had more exten-sion in the treble and bass than mostentry-level amplifiers I’ve heard.

The PrimaLuna driven within its35 watts a channel limits also haddrive and pace.

Fed a range of CDs and SACD,the sound was laced with innerdetail that was presented in anacoustic sound stage that had stag-gering depth, width and height.

But the quality that makes thiswell-priced amplifier stand out from

the competition was the musicalinsight the PrimaLuna delivers tothe listener’s ears.

The PrimaLuna’s design ensuresit is a low-anxiety device foraspiring audiophiles with little ex-perience of valve amplifiers.

The amplifier has an adaptiveaudio bias that automatically adjuststhe amount of voltage required bythe unit’s six valves, which consistof four EL34s, a 12AX7 and12AU7.

This removes the need for anytampering, save for slotting thevalves into their bases and turningon the power switch.

The PrimaLuna may well be theamplifier that turns on a newgeneration of music lovers to theseductive sounds emanating fromthose glowing glass tubes.

Highly recommended and a bestbuy.Reference Audio Video: 1800 133 135, A1

Audio: 9764 9936, Carlton Audio Visual:

9639 2737, Frankston Hi-Fi: 9781 1111

ProLogue Two Reviews

PrimaLuna ProLogue Two Just under a year ago the ProLogue One was hailed as a reference product. What could possibly better it?

Primaluna ProLogue 2 PRICE £999

Be careful what you write: it might comeback and haunt you, and maybe withfrightening rapidity. Last June, I stated

that, 'the PrimaLuna ProLogue One is now my affordable reference amplifier'. I spoke too soon.I hadn't reckoned on the ProLogue Two. From a few feet away, you can't tell the One and Twoapart. That's because they're 95% identical. And, at £999, the Two costs a meagre £200 more. I suppose it's like choosing between 1.2 and 1.4 litre versions of the same car.

Like the One, the ProLogue Two is an integrated stereo valve amplifier built on a 292 x 197 x 381mm (whd) chassis, but weighing slightly more at 17kg (37.5lb). Fit and finish are of the same high standard, with what seems like a baked enamel coating in a dark sapphire blue/green that's almost black under certain lighting conditions. However much it hurts to admit it - and I'm the last person who wants to see Bentleys made in Germany - you must

dismiss any thoughts that the Chinese have yet to achieve consistency in manufacture. The valve cage again uses banana plugs to connect cage to chassis. And that's a stroke of cleverness that all veteran tube amp users will appreciate, especially tinkerers who like to change valves with any frequency. It's just so obvious. Makes you hate amps with cages held by 16 self-tapping screws.

Beneath the cage are the four input and driver tubes, and then the primary difference between the One and Two: the output valves. While both

amps' front-ends employ two 12AX7s and two 12AU7s, the Two replaces the One's EL34s with KT88s. The result is only an extra 5W or 10W per channel, but more about that anon. Behind them are the same massive, well-made and quiet transformers. Both amplifiers feature the

company's Adaptive AutoBias automatic bias control, which constantly monitors performance and alters the bias accordingly, extensive protection circuitry, four line inputs with access via gold-plated sockets, and multi-way terminals with separate binding posts for 4 and 8 ohms.

Your £200 pays for more than the difference between EL34s and KT88s. It also buys higher quality Nichicon and Solen capacitors and higher quality superfast Philips diodes instead of the simple rectifier found in the One. Apart from the

slight increase in power, the specs remain virtually identical with a claimed frequency response of 20Hz-30kHz, ±0.5dB, THD of less than 1% at full power and an S/N ratio of 89dB. Input impedance is lower at 65k ohm instead of 100k ohm, while input sensitivity is still 300mV.

The extra power doesn't make an awful lot of difference, although the Two

certainly strikes you as more 'ballsy'

MARCH 2005 Hi-FiNews www.hifinews.co.uk

So what this gets down to is simple: does the extra £200 make a real difference? There's certainly a sense of improved refinement and precision, seemingly independent of the valve changes. Anyone who's played the 'designer components' game knows how a canny designer can fine-tune or 'voice' an amplifier with judicious use of superior parts.

But it's the change of valves that is most intriguing. Why? Because PrimaLuna only extracted slightly more power from the KT88s than the EL34s, so most of the time you won't be hearing a power-based difference. Rather, we're back to something that most of us haven't messed around with in years: debating the sonic rather than the power differences between valve types.

Some will recall that 20 years back, there was a fracas amongst valve fanciers regarding the EL34 vs the KT77, and similar battles amongst the 845 vs 2A3, and KT88 vs 6550. Even the uninterested would immediately note that EL34s are slightly warmer, more lush, while KT88s are more robust and commanding, and certainly more 'modern-sound' in the lower registers. These two amplifiers from PrimaLuna do not alter that relationship; if you already have leanings toward either tube type, then you need read no further.

Immediately, that tells you that EL34s are more 'classic valve' in their demeanour. Which suggests that choosing between ProLogues One and Two isn't simply the matter of having the extra £200. If you're in love with slightly bright speakers of limited bass performance, the ProLogue One may be the wiser option. And believe me: the extra power doesn't make an awful lot of difference in practice, although the ProLogue Two certainly strikes you as more 'ballsy' and gutsy. But how much of that is the signature sound of the KT88, and how much of it is the extra wattage?

I ran the ProLogue Two in The KK Entry Level Reference System (see panel), with intriguing results. There were times, especially playing

vintage mono recordings such as Judy Garland's Judy and some Nat 'King' Cole, both on Capitol, when the One seemed better suited: more silky, less attention-grabbing. Then I'd put on an early Columbia mono, with a characteristically 'darker' sound than Capitol's, and the sharpening-up aspects of the KT88 came into play.

So, too, with modern stereo recordings, including new CDs from Kings of Leon, Joss Stone, Jools Holland with Tom Jones and Green Day. It was reminiscent of vinyl fanatics in Japan, who keep separate cartridges tor specific labels. I found myself preferring the Two when the music needed something to grab it by the lapels and shake it up. The new Kings Of Leon CD has this overall moody, bassy, almost murky feel, and the KT88s whipped it into shape; through the One, there seemed to be a loss of fine detail. Butit favoured fragile, less textured voices.

Of course, it could go either way: the crystal-clear warbling of Alison

Krauss sounded more natural through the ProLogue Two, while the more artificial sound of a Judds CD - similar voi-ces, different produc-

tion values - were happier through the ProLogue One.

It made me think of reviewing cables; it was that unpredictable.

However, there was a deciding factor: versatility. The ProLogue Two simply cared less about what speakers you hooked up to it, and it handled the Wilson WATT Puppy System 7 with a confidence that almost made it a workable package. The oddball nature of the LS3/5A bothered it not at all, and it worked wonders with the bass potential of the PMCs. If I had my

way, one of these would be carrying M-O Valve Co KT77s, but that's a tube now so rare as to be not worth worrying about... even as a replacement valve for Radford STA25 Mk IVs which carried them as standard. That remains my fave tube, and I've always been unable to make up my mind about the EL34 vs KT88 as I never thought of them as comparable.So here's a tip, should a demo in the shop not prove to be a simple arbiter: bring along your speakers if the shop doesn't have them in stock. It's the only way you'll know. The differences aren't subtle, but neither are they mutually exclusive. Damn: it's like having to choose between Pepsi and Coke. Well, not quite. But you get my drift. The ProLogue Two stays.Ken Kessler

SupplierPistol Music 020 7971 3909www.hifi-notes.com

verdictA switch of valves, better quality capacitors and more power is what differentiates the Model One and Two, but the real differences comes down to those valves. With the EL34s offering a warmer, lusher sound.

MARCH 2005 Hi-FiNews

Hi-FiNews

'Entry Level High End'With the slightly embarrassing admission that my last reference budget amp only stayed in place from June to December, to be replaced by its slightly more powerful sibling, The KK Entry Level High End System is almost complete. The rules for inclusion are simple: the products must be in current production and no single item can sell for more that £999. So the ProLogue Two just makes it. I remain utterly committed to valves, and still searching for the turntable/arm/cartridge package that floats my boat, but here's what I use to judge everything else. Unchanged for years is the EAR 834P m-m/m-c phono stage, which now sells for £715. It remains the best phono stage I know of below £1000. The PrimaLuna ProLogue Two is my amplification of choice, while the CD player is the Musical Fidelity X-RAYV3, at £899. The system is played through PMC's sublime DB1+ 'mini-transmisson lines', circa £650 per pair depending on finish. It's the best thing I've heard in an LS3/5A-sized

cabinet without it actually being an LS3/5A. The cost of CD player, phono stage, amp and speakers is just under £3200. No, that's not cheap, but then readers of this magazine are way past all-in-for-£500 systems.

My goal, with stands such as the IF Tallis and decent cables, is to assemble an LP- and CD-playing system that will thrill and delight anyone for under £5000, right down to the mains plugs. Not being exclusionary, I also re-commend the following alternatives, for either size,

cost or taste considerations: the ProLogue One, Unison Research Unico or

Musical Fidelityt X-150 integrated amps, the Quad 99CDP CD player, the Pro-Ject Tube or NAD PP2 budget phono stages, and the Wharfedale Diamond 9, the Spendor S3/5SE and Harbeth HL-P3-ES2 loudspeakers. And when I find that elusive, killer analogue front-end, all-in for under £999, we'll try to give the entire system away in a competition.

Auditionsvalve amplifier

POSITIVE FEEDBACK ONLINE - ISSUE 18

primalunaProLogue Two integrated

as reviewed by Ed Kobesky

ED KOBESKY'S SYSTEM

LOUDSPEAKERSProAc Tablette 2000

ELECTRONICSNAD 3400 Monitor Series integrated amplifier, Rotel RC-980 preamplifier and Rotel RA-970 amplifier, Denon DRA-395 stereo receiver.

SOURCESTechnics SL-1200Mk2 turntable, NAD C521i CD player, Phillips CDR-785 CD changer/recorder, Denon DVD-900 DVD player.

CABLESAudioquest Diamondback (used to replace the pre-out/main-in jumpers on the NAD and also between the Rotel preamp and amp), MonsterCable Interlink 400MkII & 300MkII, and Audioquest Coral (to connect the digital sources), MonsterCable Z1 speaker cable, Grado 15' headphone extension cable.

ACCESSORIESMonsterPower HTS2500 isolation transformer, Record Doctor II record cleaning machine with Disc Doctor brushes, Sennheiser HD580 headphones, Sony Professional MDR-7506 headphones, Audioquest MC cartridge demagnetizer.

The most enjoyable system I've ever owned was also the simplest and least expensive. It consisted of an Onkyo CD player fed directly into a pair of Antique Sound Labs Wave DT SET amps. Those little 8-watt beauties powered my Polk RT25i monitors with surprising authority, and though the system was far from state of the art, it communicated the electricity of live music better than any I've owned since. Unfortunately, as I quickly discovered, tube gear can be finicky, especially on the budget end of the spectrum. The PrimaLuna ProLogue Two is the complete opposite. It could change everything for audiophiles who demand musicality and low maintenance. It's that important a product. Nearly every niggling problem associated with tubes has been effectively addressed, except for tube replacement, and even that has been rendered nearly hassle-free. Better still, the ProLogue Two made the hair on the back of my neck stand at attention every time I sat down to listen.

For most audiophiles, the scariest aspect of tube ownership is biasing. Tubes decay over time, and tube amp designers provide a bias adjustment to optimize current flow for the least distortion. Some amps have a built-in meter for this. With others, you need a DC voltmeter, and maybe a pair of rubber boots. You could rely on your dealer to bias your amp, but the current at his or her shop might be different than it is in your home. The ProLogue Two eliminates this concern by way of its proprietary Adaptive AutoBias circuitry. According to PrimaLuna's U.S. importer, Kevin Deal of Upscale Audio, this means no adjustments, ever. You don't have to use matched pairs of tubes, or even the same type. If a KT88 blows out, you can temporarily replace it with an EL34 if that's all you have on hand.

As with all tube amps, you'll need to replace the tubes every few years. Exactly how often depends on your listening habits. Some people get lucky, others don't. The good news is that if you can change a headlight on your car, you can retube a ProLogue Two. The tubes should cost between $100 and $200—not exactly trivial, given the fact that you can buy a very good integrated amp for that much. Then again, it won't be as unique as the ProLogue Two.

The only other special consideration regards cooling. Like all tube amps, the ProLogue Two needs open space on all sides, more space than a solid-state amp. If you can't give it at least four to six inches of space above and plenty around the sides, you'll want to put it on the top shelf of your rack or on a separate amp stand to avoid heat-related damage. Everything else you might worry about is handled internally, as the ProLogue Two hass a soft-start circuit to gradually bring the tubes on line, and an easy-to-replace fuse for protecting the output stage.

Obviously it's practical, but the ProLogue Two is also plenty sexy. Available with the buyer's choice of silver or black faceplates, it sports a high-gloss lacquer finish in "black sapphire" (actually a blue-black) and a build quality that's nothing short of stunning for the price. A pair of white gloves is provided so you don't smudge the finish—a classy touch. Kevin Deal triple-boxes every unit, and mine traveled from California to Pennsylvania without so much as a nick. There's no setup required aside from removing the foam tube protectors and plugging it in.

Kevin Deal insists that reviewers take the bottom off and have a look for themselves, and I was not about to resist. I saw point-to-point wiring—a nice touch, but not as uncommon as it used to be in budget gear. What is uncommon is the overall care of assembly and wire dressing. How they accomplish so much for so little money is no mystery—the ProLogue Two is assembled in China. For $1445, you even get a removable tube cage. It snaps on and off instantly. I left mine off because I couldn't

bear to keep those gorgeous KT88 tubes all cooped up.

While the front of the ProLogue Two is the main attraction, the back looks pretty good as well, with a complement of beefy, gold-plated terminals you'd expect to find on a much more expensive product. If you're like me, you'll be giddy long before you tap the power switch.

Now comes the hard part, which is describing the sound of the ProLogue Two. Should I compare it to similarly-priced tube gear? I could, but much of its competition aims for a purposely soft, romantic sound that is initially appealing but unsatisfying in the long

run. I could compare it to solid-state integrated amps I've owned in its price category, but they all seemed to shoot for maximum slam and detail. I decided to throw all comparisons aside and simply tell you what I heard.

The first thing I noticed was a unique sense of air and aliveness. Even before Keith Jarrett played his first note on side one, record one of the monolithic 10-LP box set, Sun Bear Sessions (ECM 1100 ), there was more atmosphere than I'd ever heard. It was downright eerie, and for some listeners, it could be revelatory. Get ready, analog fans: LP + KT88 = a synergy that's not to be believed.

When the music started, the ProLogue Two surprised—no, shocked—me by painting a smooth sonic picture that was also controlled and coherent. Many tube amps I've heard are slow in the midrange, dull on top, and loosey-goosey on the bottom. Not the ProLogue Two. It can't compete with solid-state amps in terms of tightness and fastness, but it never sacrifices detail to provide a warm, soothing presentation. It just sounds good, and not in a deliberately tube-like way. Music is presented in its entirety. At moderate to medium-high volumes, it does a remarkable job of sorting out instrumental lines, right down to the individual notes. I'd have no qualms about pairing it with sources and speakers that cost many times its absurdly low price. It also brought out the very best in budget gear. Whether fed the signal from my NAD C521i CD player or a $50 Sony CD Walkman, the results were musical. The ProLogue Two can be alternately forgiving and revealing. That, in a word, is magic.

The ProLogue Two never put a foot wrong. It's the first amp I've heard in a long time that could bang out bass-laden hip hop tracks, as on The Streets' CD Original Pirate Material (Atlantic 93181), then turn on a dime and resolve the fragile shadings of a minimally-backed female vocalist like Holly Cole on her Tom Waits tribute record, Temptation (Metro Blue 8316532). It was human, expressive, and open sounding to a fault. The only way you'd outgrow this amp is if you upgraded to speakers the size of a Kia, and even then, the ProLogue Two could probably power them to a reasonable volume.

There's another reason to consider the ProLogue Two. If you don't like the sound of your solid-state amp, you're pretty much stuck unless you're willing to risk going in with a soldering iron to replace resistors and capacitors. Even then, the benefits are usually subtle. Not so with tubes. You can have a blast trying different tubes until you get precisely the sound you want. It's a relatively cheap way to stave off an acute case of upgrade-itis.

The PrimaLuna ProLogue Two may not be as energetic as a solid-state amp, nor will it exert the same level of control. That, however, is the key to its appeal. Music flows through it gracefully. What comes out is lush but not slushy, alive but not prickly, and involving as all get out. The PrimaLuna ProLogue Two garners my strongest recommendation. It's not merely a great tube amp, but a great amp, period. Ed Kobesky

ProLogue TwoRetail: $1445

Upscale Audioweb address: www.upscaleaudio.com

PrimaLuna ProLogue TwoPrimaLuna ProLogue Two

Black VelvetBlack Velvet

Distribution: Aquarius Hi-Fi

Contact: 210.8834.718

Price: 1.470 Euro

Verdict: 4.6

WORDS: PARIS KOTSIS

Welcome to the main menu of PrimaLuna sound experience…

You may feel bad about Chinese-made

products, but when it comes to PrimaLuna,

that all changes. The company from the

Netherlands that created a world buzz with

its ProLogue One integrated amplifier, has

already unveiled at the CES a preamplifier

and two power amps based on EL34 and

KT88 output tubes. Notewor thy to the

preamp is dual mono architecture with tube

rectification and choke filtering, independent

for each channel. The "Made in China" as-

pect is, of course, only one part of the story.

The other part is quite different and rather

revolutionary: a special, custom-made output

t ransformer designed in the US, and a

special, patented circuit that checks and

adjusts the bias in a constant, automatic way.

You no longer need worry about aging tubes

or "matched pairs." So there you have it:

great value/money ratio and user friendli-

ness, both terrifically rare among tube am-

plifiers.

Of course, success doesn’t come easily for

any hi-end product unless there is some

serious sound designers behind it. Unlike

other manufacturers, PrimaLuna is not one-

man show, but rather a team effort, with

silent partners such as former Goldmund

designer Marcel Croese. Heading the team is

Herman van den Dungen, a highly capable

person. It’s true that these days one can see

PrimaLuna amps everywhere, with scores of

rave reviews and awards. As some "doub-

ters" have stated, PrimaLuna must have its

way in the worldwide press, more so than

other manufacturers. While this could be

true, it’s also misleading to think that way.

The review process in general is completely

d i f ferent now wi th the explos ion of the

Internet (dedicated web sites, chat rooms,

bul let in boards, etc.) and no magazine

—especially a famous one that wants to

retain its reliability—could afford to ignore the

buzz about a giant-killer amp.

The second incarnation of PrimaLuna’s integrated amp, the "ProLogue Two" retains the

construction and aesthetics of the "One," as well as the input and driver tubes (ECC82, ECC83),

however the output stage is now two pair of KT88s providing 40 watts per channel. Small yet

important changes include utilizing more capable, ultra-fast diodes in the power supply and

Solen Tin Foil caps in the signal path (instead of the Realcaps of the ProLogue One). Overall

construction is superb, with ceramic bases for the tubes, encapsulated/shielded, custom output

transformers, torroidal power transformer, hard-wired signal path, a choke filter and of course

that beautiful blue-black gloss. The amp also has a soft-start function and of course, the auto-

bias feature.

BIG & SECURE

Two months ago, I was quite lucky to receive the ProLogue One after it had been properly

broken in by the retailer. Unfortunately, that was not the case with the Two, which came to me

with no play time whatsoever. The first 2-3 hours were good, but then everything collapsed into

a heavy, dark, shut-in sound. It was only after 150 hours of use that the amp started to shine

again and at around 250 hours, it settled in with its final sound. I asked the ProLogue Two to

drive the high-sensitivity Horning Hybrid Agaton and my own custom, high-sensitivity, 3-way

speakers. I also tested it, under harder conditions (a small room) with the Harbeth Monitor 40.

All met with resounding success. These big speakers can be very hard to follow unless the amp

has serious resolving capabilities and bass power. ProLogue Two certainly has this capability

which is why I prefer the KT-88 over EL 34: it creates a bigger, deeper soundstage; it portrays a

fuller body experience throughout the midrange; it goes further into the deep bass and extended

highs; and last but not least, it sounds to my ears more neutral, with a more balanced tonality. It

is the tube of choice in my single-ended amp (Unison P30K) but now, with the ProLogue Two,

the time has come to enjoy the KT-88 in such a rare push-pull design.

So the ProLogue Two seems to be the big brother of the P1, both in price and sound. Never-

theless, it is equally clear and distortion free; like having the same DNA, which in this case is

metaphorically true. Compared to the single-ended Unison, the ProLogue Two is quieter, has

FEATURES

Power: 40Wrms

Fr. response: 20Hz-30KHz (±0.5dB)

Inputs/outputs: 4 line/ 8&4Ohm

Consumption: 300W

Dimensions: 39x27,5x19 cm. (WDH)

Weight: 18 kilos

less harmonic distortion and possesses equally dense definition but can’t equal Unison’s rhythmical ability, aliveness and texture. Spea-king from memory now, ProLogue Two is not as huge as Graaf GM50 but is more balanced in tonality and quieter. This is the point at which the PrimaLuna sound excels: it is dead quiet and distortion-free, factors that can be easily heard and measured in the lab (actually both PrimaLuna amps provide the best measurements I’ve ever taken on tube amps). But this is not accomplished at the expense of beauty. Instead, midrange is magical, palpable and three-dimen-sional; full of tonal colors, with almost no trace of crossover distortion. This is indeed a fresh, new sound approach regarding push-pull designs.Summing up, ProLogue Two is a bullet-proof amplifier that deserves a BIG 5 STARS for its combination of sound purity, high quality construction, driving ability and the ergonomics it offers. It was no surprise then that I bought the review sample, as it was easily welcomed by my speakers as well as my heart. It is almost always powered on, without showing any sign of stress, instability or over heating, and it is always capable of producing velvety sounds with delicate transients and mirror-like, grain-free treble. If I weren’t such a fanatic about single-ended sound, I don’t think I would search for anything else after having auditioned the ProLogue Two. I would just partner it with a proper monitor speaker and a tube-based CD player (as it is utterly revealing of other component’s sonic signature), and simply enjoy my music thereafter.

Lab ReportProLogue Two reached flat (-0,1dB) at 10Hz and at 77KHz (-3dB), a fine response for a tube amp. Noise was again exceptionally low, reaching at –72dB, a solid state territory of quietness. Distortions were slightly more than ProLogue One, at 0,15% (instead of 0,1%). Lastly, power was measured at 37W@5% THD, from both 4 and 8 Ohms taps, while keeping distortion at 0,3% THD (solid state standards) it still produced a healthy 14W (like ProLogue One). An overall superb lab report.

PrimaLuna ProLogue Two reviewRob Henckens

I must admit it was already in October 2004 that I ‘subjected’ my ears to the magical tube sounds of the PrimaLuna ProLogue Two. Now that I am finally ‘recovered’, I finally get around to finishing my story. The complete tube story. The part about ‘recovering’ is of course just a joke, but it doesn’t hurt to put some time between the actual auditioning, judging, absorbing, and typing in of ones impressions. Of course, we are enthusiastic as ever: here at audioforum.be, you read nothing but enthusiastic texts from editors who are wild about certain products. Components and/or speakers that charm in a certain way; that’s what we love to write about. Allow me to introduce to you one of the cheapest and most reliable integrated tube amplifiers.

The PrimaLuna ProLogue Two is the second amplifier in a product line that embraces affordable quality. With its 2 X 40 Watts, this guy delivers quite a lot of power for a tube amplifier. About the only essential difference with the ProLogue One is the power tube used: the One uses the EL-34, the Two boasts the KT-88. The design was kept simple, with the most important components in a casing (not including the tubes). The folks at PrimaLuna simply couldn’t deny us the charm of the pre- and power tubes, so they fitted them in the front of the ‘board’. You should see this at night! All coziness and warmth!

Specs

Power: 2 x 40 watts

Frequency range: 20Hz-30kHz +/- .5db

THD: < 1% at full load

Signal-to-noise Ratio: 89 db

Input sensitivity: 300mV

Power use: 300 watts

Size: 15.5" x 11" x 7.5"

Weight: 37.5 lbs

Inputs: 4 pairs RCA

Outputs: 4 & 8 Ohm connections

Expectations

Personally, I didn’t really know what to expect, as I had never heard a tube before! Here and there, one picks up statements like warm sound (those tubes, of course), analogue sound, flowing sound, rest, musicality, and rhythm. Would this PrimaLuna be able to live up to all these expectancies? Well, to be honest, I didn’t set any expectancies, because I had never heard tubes before. The sound from my own setup tends to be on the analytical side. At the level of my speakers and behind them, it creates a wide stage with good detail. I absolutely can’t complain about the lows either, given the space and speaker type (bookshelf). I’ve got slam, attack, and pressure. Some instruments tend towards ‘thickness’ (recording!), but only seldom so. I also like the placement of the different classical instruments. I can listen to that for hours. Whether this sound is ‘the’ sound, I don’t know, but it’s ‘my’ sound, a reference for me.

Meanwhile, I have been avidly extending my frame of reference, by listening to different setups from other audio forum participants. What if this tube amplifier produces an entirely different sound? Will it appeal to me? But then, the sound may be similar to my own. Time to heat up those tubes…

Listening impressions

So what’s with the story that a tube needs to heat up first to spread its glow across the sound? It is true, at least in my experience. At first, the amplifier literally sounded a bit ‘cool’, but once those tubes heated up, the thing came alive! I can reassure you, though: there is no day-and-night difference between this sound and my own. What struck me was that you start listening in a less concentrated way, allowing the music to come at you instead. Thus, your attention focuses on the music only. So a tube sounds nice and musical, let there be no doubt about it. The placement was certainly there, only rounder, vaguer, more fluent. Voices sound full, homogenous, and glowing (e.g., Diana Krall - Love scenes). The PrimaLuna ProLogue Two was definitely capable of driving my speakers to satisfaction. Are there no differences then? There are! My solid state amplification has more power. This became especially clear with the attacks in dynamic parts (e.g., Stravinsky - Firebird). Mind you, these are not painful observations, just marginal differences.

During the review period, I auditioned the amplifier with both CDs and analogue LPs (cf. review Clearaudio Emotion). And boy, what an experience the latter were! All the good characteristics of this amplifier are highlighted even more with LP reproduction. LPs pay more attention to the music than CDs: a more general presentation leads to less fixation on details and a greater sense of music as a whole.

Conclusion

In general, the PrimaLuna ProLogue Two rocks. It scores on musicality, involvement, and easy listening! This makes for an exceptional price/quality ratio. With its very palatable price tag of €1.379, it should be in your top 3 of must-audition amplifiers, if you are considering buying in this price range. Highly recommended! Hi-Fi+ feels the same way, they elected the amp 'Product of the ear'.

Short software list Stravinsky - Firebird suite - Decca (LP)Dave Brubeck - Greatest hits - CBS (LP)Chat Baker&Philipe Catherine - Cool Jazz – LDH (LP)Diana Krall - Love scenes - Impulse (CD)Nils Lofgren - Acoustic life - Vision (CD)

Tutti orchestral sampler – Diverse - Reference Recordings (HDCD)

Review systemB&W N805 with Signature phase plugsAtacama Nexus 6 speaker stands, filled with Atabites (on tiles of Belgian blue stone)Parasound Halo P3Parasound Halo A23NAD C541i with Tentlabs XO2 modificationKimber Select KS-3033 speaker cableKimber Select KS-1111 XLR interconnect (P3 - A23)Kimber Select KS-1011 RCA interconnect (NAD C541i - P3)Vibrapod Isolators & ConesSunleiste multiple socket (6)

Selfmade rack with rubber disconnection

Useful links:

Website PrimaLuna

Dealer Technology Factory

Website Upscale Audio

ProLogue Three & Four Reviews

ProLogue Three & Five Reviews

The PrimaLuna Prologue Threepreamp and Five power amp areat the top of my list: good sound,

good value, simplicity. They are alsogood fun, if you like playing with tubes(the power amp is built to accept manytypes of tubes, including the EL-34),but you don't need to play with tubes.You can be a complete tube neophyteand enjoy these units. They fill theroom with exquisite sound, from thewhisper of a stroked cymbal or mutedviolin to the foundation thunder of agreat organ. That's the key: TheProLogues make music; they make itsimply; they make it well.

And they are tough, something Idon't expect in tubes. These 1980s-looking units, with their metal cageshousing small fierce-eyed beasts,were delivered in good shape by UPS,along with some other boxes, andplaced in a stack at my gate. Before Icould get to them, a jackass, aboutwhom no more shall be said, hadknocked the top bo x nearly fou rfeet to the ground, and had eatenthe cardboard.

So well packed, so sturdy, arethese units, though, that not only wasno damage done to the inside box orthe outside of the unit, but when Ihooked the ProLogues up to check for

internal damage, I had, instead, glori -ous music in under five minutes. Itwould have been under three minutesexcept I was in a quandary aboutwhether to hook up the Spendor S8espeakers to the 4-ohm or 8-ohm out -

puts on the ProLogue Five. The 8-ohmtaps won the day, and I haven'ttouched the units since except to turnthem on and play music.

And what music! In an outdoormarket recently, I heard a group ofthree astonishing young musicians,

calling themselves Sneakin' Out. I ama devotee of local musicians; they playfor the moment and from the heart;they play for their souls and for ours.Their music reflects what is in front ofthem and inside us, with an immediacy

of emotion and sound that I never getfrom polished, distant stars, no matterhow complex the composition andplaying skills. Dave Daluka, the man -dolinist (playing an electrical instru -ment) and D. Louis-HensonBlankenship, percussionist, areamong the best players I have everheard in jazz and pop. I sat on thegrass enchanted, while folks aroundme gorged on berries and tickled dogsand babies.

Yes, Sneakin' Out has a CD, TrainWreck [www.sneakinout.com] that fea-tures, as does their live music, a mix ofjazz, pop, and folk, much of it writtenby the group, and all of it interestingand wonderfully played. My favorite isa take on Jagger and Richards' "PaintIt Black." Daluka plays with subtletyand extraordinary speed, and yet with

Sallie Reynolds Equipment Review

PrimaLuna ProLogue Three Preamplifier & ProLogue Five Power AmplifierTube gear that blows minds—not budgets.

If you like organ music, and don't believe any 36Wpc ampnot in the price range of a trip to far galaxies can impart thewhole body-shaking experience, you need to hear this pair.

ProLogue Five Power Amplifier

great feeling, his mandolin driving thesong. Occasionally Blankenship willpick up a line and then sweep into tin -kling transformations on his electrifiedxylophone. He will make you gasp.Through the ProLogues, this musicwas as clear and immediate as it wason the lawn—maybe more so, sanscrowd. But that feeling, of real peopleplaying for real people, is the draw ofthis kind of music. Buy this CD. Andplay it on the ProLogues, which youreally should hear before you buy apreamp and amp.

Why? Well, reason one: If you likeorgan music, and don't believe any36Wpc amp not in the price range of atrip to far galaxies can impart thewhole body-shaking experience, youneed to hear this pair. The GreatOrgan at St. Mary's Cathedral[Reference Recordings] is one of mytoughest tests for any equipment. Theonly amplifier I've had here that canreproduce its sensations and range,from the sweet ringing "Carillon ofWestminster" to the pedal note ofClarke's "Trumpet Voluntary," isMusical Fidelity's big kW500 integrat -ed (which is a hybrid tube/transistorunit, but one whose tubes are discreet-ly concealed—not up on display intheir own little go-go cage), whichcosts $7000. The ProLogues, at about$2600 the pair, give the MF a prettygood run. They not only produce thenotes, but like the kW500, let the

organ melodies develop, rich andwarm, in the swelling storm of theorgan. The kW500s, of course, get thewhole organ more fully and richly, butsince it is about 10 times more power -ful, it can, and it should, drive power-hungry loads beyond the capacities of

the ProLogues. But the ProLogues aresurprisingly good with this music.Eugene Gigout's "Scherzo" is a beau -tiful, intense, and surely difficult piece.It's almost enough just to do it, to mis -quote an old horse-chestnut, but to doit well surpasses expectation. Here it is

quite lovely and moving. I was hearingdetails in certain ranks of pipes in waysI hadn't before. And again, the immedi-acy was magical.

Reason two: If you like tubes, you'llfind the ProLogues' warm, rich soundmost wonderful. And there is bass—true, clean, deep, tight bass. I didn'tuse a subwoofer on the Spendors inthis review and didn't need one.(Largely owing to the extension of the

speakers, of course, but I've found thatsometimes a sub props up an amp'sflagging bass.)

The high frequencies are sweetand smooth, and completely withoutsugar coating. They too are clear andtrue. Indeed, this is the clearest treble

I have heard. The transients of cym -bals and bells are so shimmering, soswift in onset and decay, I foundmyself looking around to be sure thetuned wind chimes by the windowwere tied down for the duration.

The midrange, where the mainbody of music lies, is rich, powerful,and again, simon pure. If I have onetiny itch about these units, it is that theupper regions of this range may be—to a small degree—emphasized. Thiscould be a feature of recording tech -nique, unnoticed even on belovedrecordings till now. I note, especially inanother great "local-musician" CD,Sweet Sunny North [Shanachie,recorded throughout Norway], that itseems to be the featured player(hardanger fiddle, jaw harp, or singeron that disc) who is a touch forward,rather than a slice of frequencies.

The ProLogues' soundstage isgrand, in all senses of that word. In just

The ProLogues' soundstage is grand, in all senses of thatword. In just two days of break-in, it reached satisfyingproportions, and has such good height I didn't think aboutit till it suddenly occurred to me that the players I heardthrough the ProLogues sounded as tall as real humanbeings do.

ProLogue Three Preamplifier

two days of break-in, it reached satis -fying proportions, and has such goodheight I didn't think about it till it sud -denly occurred to me that the players Iheard through the ProLogues soundedas tall as real human beings do.

Reason three: If you think you don'tlike tubes, if you dub them tubby, toosweet, too "comfy," you'll find in thesethe precision of the best of solid-stateunits, plus—like vinyl—an added musi-cal soupcon that no one has satisfac -torily explained to me. Because ofinherent potentials for distortion, nei -ther vinyl nor tubes should sound asmuch "like music" as they do.(Incidentally, though the Three doesnot come with a phonostage, aProLogue PhonoBoard—moving mag-net—is available for $159 and can beinstalled in the unit.)

Reason four: If you've been afraidthat tubes were frail, hard to set up,hard to keep biased, forever going onthe blink—rest easy. The PrimaLunadesigner, Herman van den Dungen,has done what good designers every -where should do. He has created

excellent sound with top-grade partsand design at a reasonable price, inunits that are reliable, easy to use, andseemingly indestructible.

Finally, if you have always wantedto be a reviewer, but never dared, youcan live out your dream. PrimaLunainvites you to "send us a review of yourexperience with the amplifier."

So—wear yourself out.

MANUFACTURER INFORMATIONDUROB AUDIO BVwww.primaluna.nl

DISTRIBUTOR INFORMATIONUPSCALE AUDIO2504 Spring TerraceUpland, CA 91784(909) 931-9686www.upscaleaudio.com

SPECIFICATIONSProLogue Three vacuum tube stereo preamplifierNumber and type of inputs: Four stereopairs, line level (via RCA jacks)Type of outputs: Three stereo pairs, linelevel (two mains, one tape, via RCA jacks)Dimensions: 15.5" x 11" x 7.5" Weight: 23.5 lbs., shipping weight 27.9 lbs.Price: $1295

ProLogue Five vacuum tube stereo poweramplifierNumber of channels: TwoPower output: 36WpcNumber and type of inputs: One stereo pair,line level (via RCA jacks)Dimension: 15.5" x 11" x 7.5" Weight: 37.5 lbs., shipping weight 41.9 lbs. Price: $1295

ASSOCIATED EQUIPMENTSpendor S8e loudspeakers; Musical FidelitykW500 amplifier and A5 CD player; Monster3500 power-line conditioner; Nordost BlueHeaven speaker cables and interconnects.

STRENGTHSClarity, power, transient speed, and accuracyacross th e frequency range-fantastic.Reproduction of instrumental subtleties andsoundstaging-addictive. Ease of setup anduse, sturdy construction-almost unmatched,and comforting. WEAKNESSESA possible slight exaggeration in the midrangethat may be from other sources, revealed by theProLogues. I wish I had time to ask the distribu-tor for a set of "upgrade" tubes.

ProLogue Three vacuum tube stereopreamplifier and ProLogue Five vacuum tube stereo power amplifier

MANUFACTURERCOMMENTS

On behalf of Herman and me, we would liketo say thank-you to Sallie Reynolds for sucha wonderful review! With Sallie having somuch industry experience and ears tomatch we are honored.

I should mention the amplifier sounds theway it does due to our proprietary AdaptiveAutoBias circuit which will keep the powertubes operating in an optimum range notonly as music plays but as they age, andnever need biasing.

The preamp breathes life because it is atrue dual-mono with two toroidal transform-ers, tube rectification, and uses the AlpsBlue Velvet potentiometer. I can't think of apre-amp at anywhere near this price thatoffers these features.

When Sallie mentioned reliable, readersshould know both products have a SoftStartcircuit to all but eliminate thermal shock tointernal components and tubes when unitsare turned on. This, along with extensiveuse of point to point wiring and not stress -ing components means a long life. As ofthis writing, we have zero failures in thefield with hundreds or PrimaLunas sold inNorth America. We know people are busyand that this is supposed to be the "funstuff."

Kevin DealUpscale Audio

The e-journal of analog and digital sound.

no.1 2 0 0 5

premier issue

TONE INTERVIEWS JAZZ GREATJACQUI NAYLOR

The Monogamous Audiophile:One Man’s Continuous SpeakerPassion

FINd A GREAT SYSTEM ON A BUdGET

Steve Hoffman Tells Us Why The EPIFANIA LINE STAGE Is Sweet Heaven

REBUILdING CLASSIC AMPSOR: An Outlet for Geek Energy

Music You Need To discover

Amplifiers From Pacific Creek, Prima Luna and WAVAC

A little over a year ago PrimaLuna came on the scene with their

ProLogue 1 and 2 integrated amplifiers that featured simple tube

circuits that were well executed and flawlessly assembled in

China. Regardless of whether you liked the EL – 34 or KT – 88

version, these gorgeous little amps offered a lot of sound for

the money. Working for another audio publication at the time,

I was one of the many reviewers that heaped a lot of praise on

PrimaLuna, and Kevin Deal at Upscale aUdio for bringing this

gear to the US. (continued)

— Jeff Dorgay

R E V I E W

T oday, we have some additions to the line. The ProLogue 3 is an all tube preamplifier and the ProLogue 4 is an EL – 34 based

power amplifier, while the ProLogue 5 is a KT -88 based power amplifier. The ProLogue 3 is $1295 with a silver or black faceplate, the ProLogue 4 is $1045 and the slightly higher powered ProLogue 5 is slightly more expensive at $1295. While the integrated amplifiers sounded great and offered a tremendous value, getting the components onto separate chassis with separate power supplies has its advantages. As I was very familiar with the EL-34 sound of the ProLogue One after my re-view and subsequent purchase, (it now resides in music editor Norwood Brown’s system) I wanted to try the KT-88 version this time around.

Technical Overview

First of all, these babies are built like tanks. Though they come in fairly compact packages (11” W x 16.5” D x 7.5”H) the power amplifier weighs in at a hefty 36 pounds and the preamp at 17.5 pounds. If you have never seen a PrimaLuna product up close, they are a treat. Elegantly un-derstated, the chassis are finished in a very dark blue metallic finish that is all but black unless you look at it in very bright light and has the same level of gloss and smoothness you would expect to see on a classic car at Pebble Beach. A cage is supplied to keep prying hands away from the tubes, but if you are without small children or in-quisitive pets, leave them off so you can see the tubes glow!!

The ProLogue 3 uses a pair of 12AX7s and a pair of 12AU7s with a modest gain of 11.5db and is subsequently very quiet for a tube preamp, especially one in this price range. The treat here is that it uses a pair of 5AR4 rectifier tubes in the power supply, keeping the dual mono concept throughout. All the tube sockets are heavy duty ceramic and all wiring is point to point. There are four sets of inputs, a tape output and a pair of outputs so that you can use it in a biamped sys-tem or with an amplified subwoofer.

The ProLogue 5 uses the same tubes for the input stages and a pair of KT-88s for each chan-nel of the output stage. No negative feedback is used in this amplifier and while it has solid state rectification, it does feature diodes of the fast re-covery variety. As in all PrimaLuna amplifiers, the ProLogue 5 uses PrimaLunas’ patented Adaptive auto bias system, so it is not critical to have out-put tubes that are matched pairs to achieve good performance. I have talked to a number of differ-

ent designers and the jury is out on whether it is better to have auto bias or fixed bias that is ad-justable by the end user. The PrimaLuna system works well and the sound quality is wonderful, so they have the right formula here. (Personally, I think it re-ally helps the recent converts to tube world, not having to screw around with biasing duties…) There is a soft start circuit in the power supply, so tube life should be very good. We are keeping these two for a long term test, so we’ll keep you posted in a later issue. Note: Along with the soft start feature, the ProLogue 3 does not make a loud clunk or thump, should you turn it off before your power amplifier. This is a very nice touch in a preamplifier at this price range.

Both units have detachable AC cords and come with pretty substantial power cords right from the factory. The input RCA jacks are top quality and the binding posts on the output of the amplifier are very beefy WBT-style connectors. The front panels are a model of simplicity and the power switch is a large rocker on the left side of the chassis, which adds to the clean look.

Setup and Associated Components

If you have picked up any audiophile maga-zine lately, you know I love the sound of the Prim-aLuna integrated amplifier, and the separates take the PrimaLuna sound to another level of refine-ment. Right out of the box, they sounded fine, but after about 25 hours had settled into really good sound, with a slight improvement after 100 hours.

For those of you that produce megabucks

gear, you better hope the folks at PrimaLuna

don’t start doing R&D at a higher level on the

audio food chain, they definitely make

gear that rocks!

(continued)

R E V I E W

©2005 Tone Audio Printed with permission from Tone Publications. All rights reserved.

R E V I E W

will be way too loud for your neighbors anyway. Besides, that’s not what a small tube amplifier is about, it’s about warm, smooth detailed sound, not brain damage volume.

Because of the KT-88 tubes, the ProLogue 5 is a bit drier sounding than the EL-34 ProLogue 4, but it has a bit more punch and a touch more bass authority and control, so the sound you prefer is up to you. Again, system matching is important and you need to make sure you get a pair of speakers that is synergistic. There are also a few work arounds that we willdiscuss in the next section. Thanks to the adaptive auto bias, if you would like to tune the sound of your ProLogue 5 a bit, you can roll in a set of 6L6 tubes. I just happened to have a pair of Electro-Harmonix 6L6 tubes on the shelf, and the results were interest-ing. Not quite as liquid as the EL-34, yet not as dry as the KT – 88, but a bit less power. Depend-ing on your taste and speakers, this may be the Goldilocks tube for the ProLogue 5! Thanks to the soft start circuitry and adaptive auto bias in the ProLogue 5, tube life should be excellent.

This combination has a very smooth sound without being rolled off or overly warm or too lush. It almost sounds more like good solid-state gear, with that extra bit of dimension that just can’t ever quite be achieved with solid-state. Obviously with 36 watts per channel, you can’t crank up the orchestral music or listen to Genesis at Earth shattering levels, but used within its range, the PrimaLuna combination does quite nicely.

What I enjoyed the most about this gear was that it had a very neutral midrange, smooth highs and a very wide soundstage, allowing for a lot of air in the presentation. No matter what speakers I used, the PrimaLuna pair did a great job with vocal harmonies and music that was somewhatdensely packed together. How Can You Mend a Broken Heart by the Bee Gees (Trafalgar, MoFi LP) served up great separation between the individual members as did Wood-face by Crowded House (Simply Vinyl, LP) and all of my Crosby, Stills and Nash discs. Again, this is the kind of sound tube lovers live for!

It wouldn’t be an audiophile review unless we listened to some female vocals, so my standards (Ricki Lee Jones, KD Lang and Peggy Lee; LP and CD) all got plenty of rotation, but I really en-joyed Jaqui Naylor’s new live CD, East/West. This really put the ProLogue 5 to the test, because it is a very dynamic recording. Even at a fairly high volume level, the image did not fall apart.

Once burned in, these two warm

up pretty fast and are very groovy after about 30 minutes.

The majority of my testing was done with the Roan Audio model 5 minimonitors which are rated at 87db and have a load of 8 ohms. To mix it up a bit, I also used the Definitive Technolo-gies P700 powered monitors that have a 92db efficiency as well as built in powered subwoofers. If you really like to listen to music loud, this was a great alternative choice. My trusty Naim Arivas (4 ohm, 90db) got rotated into the test system for a while and were not the best choice for the Pro-Logue 5, but when I swapped the ProLogue 5 for the Monarchy SM 70 Pro monoblocks, it was a wonderful combination with the ProLogue 3 pre-amp. (more about that later) Most of my source material was digital, using a combination of the Modwright Denon player and a Jolida CD100A tube CD player.

Our review of the Roan speakers is going to be in the next issue of TONE-Audio, but I can tell you that they are a very neutral sound-ing speaker and are easy to drive, so they were a nice match for the PrimaLuna combo. I also felt that for $1500, they might be representative of what you might purchase to go along with $2300 worth of amp and preamp. Keeping this in the budget, I used the DH Labs Air Matrix in-terconnects between amp and preamp as well as between preamp and disc player. Speaker cables were DH Labs Silver Sonic T-14.

The Sound

This amp/preamp combination produces great sound and is very musical. Detail at low to medium levels is very good and it doesn’t really compress until you push it very hard. Even then it is pretty polite, but like the ProLogue 1, the ProLogue 5 gets to a certain point where it just will not play any louder and the soundfield just collapses back on itself. It’s kind of like my old BMW 320i, it will get up to 100mph pretty quick, but after about 110, its out of power. For most of you though, if you choose your speakers on the more efficient side, this will occur at a level that

(continued)©2005 Tone Audio Printed with permission from Tone Publications. All rights reserved.

R E V I E W

While the ProLogue 5 will do an admirable job of playing music with low bass, it also had very good control over the bass. This is an area where the separate components with their own power supplies really allows a much better musi-cal presentataion than the PrimaLuna integrated. The integrated is very good, but if you can spare the extra $1200 bucks (and shelf space) you will be glad you went the extra mile. Listening to Mo-ments in Love by the Art of Noise (CD) and even my old favorite, Dark Side of the Moon (MoFi LP) left me very impressed with the bass perfor-mance of this pair.

High frequency response was also very good, and transient attack was fast, but in some cases just a little bit overdamped and lacking that last bit of air that a $5000 dollar preamp would have. But wait, this is only a $1300 preamp and that’s the kicker. The longer you listen to this pair, you would swear you paid a lot more for them. Ev-eryone that stopped by for a casual listen were floored when I told them how reasonably priced they were. Whenever I switched back from my reference system, I was always very happy with the level of resolution I was able to achieve with this pair. I spent a lot of days with the PrimaLu-na pair on for 10 – 12 hour days with no fatigue. Switching to a modest turntable provided an even more liquid presentation, this gear is definitely up to the challenge.

The Phono Option

For $159, you can add a phono input to your PrimaLuna ProLogue 3. They make a great little module that can be installed by Upscale Audio (call them to inquire about installation pricing) or if you have good vision and reasonable soldering skills, can install yourself in about a half hour. It is a very small little board though, so if in doubt, have it installed.

I installed one in my ProLogue One and it is a great value if you are an occasional vinyl user, or aren’t planning on spending a ton of money on a table. I had great results with Sumiko’s Debut III, which already had an Ortofon cartridge prein-stalled. This is one of the best $300 tables I have ever heard and did a great job with the onboard phono section.

To take things up a notch or two, I substi-tuted a Rega P3 fitted with a Shure V15, but was able to get more performance by using an outboard phono stage, in this case the Sumiko Primare R20 ($695). Again, for $159, this repre-sents tremendous value and sounds as good or

better than a lot of built-in phono stages I have heard, but if you are a serious vinyl enthusiast, the ProLogue 3 is so good, you will benefit from the phono preamp of your choice. Kudos to Pri-maLuna for offering this flexibility.

The Sum of its Parts

There was one big surprise here though. While I think the PrimaLuna pair is quite good, if you are just in the market for a preamplifier, don’t rule out the ProLogue 3, even in a bit spendier system. Thanks to its dual mono design and tube rectifi-ers in the power supply, this one is a real sleeper, kind of like an Audi S4 with the badges removed. You pull up at the stop light thinking you know what’s under the hood and then get left in the dust when the light turns green.

Being from the Badger State, I’m nosier than I prob-ably should be, but I couldn’t resist dropping the ProLogue 3 in my reference system with all the tweaks to see how it would do. Granted it was not as open or accurate as my Emotive Au-dio Poeta, but it was really damn good and out of this world good for a $1300 preamplifier. Believe me, the ProLogue 3 was no disgrace with a few thousand dollars worth of interconnects hooked up to it and a Symposium Ultra base under it. You could easily make the ProLogue 3 preampli-fier the cornerstone of a more expensive system. Everything I heard with the ProLogue 5 amplifier was even more apparent on my big system.

The VeRDiCT

For those of you that produce megabucks gear, you better hope the folks at PrimaLuna don’t start do-ing R&D at a higher level on the audio food chain, they definitely make gear that rocks! For those of you look-ing for high quality, reasonably priced hifi and want to enjoy all the things that make tube gear great without any of the hassle, look no further, this pair’s for you. If I had to buy a system, keep the budget under five grand and I had to keep the system forever, this is the amp and preamp I’d buy. PrimaLuna has hit another one out of the park with great sound, great build quality and dashing good looks. Highly recommended.

As is typical, an amplifier and preamplifier that are designed together usually work quite well together and these two are no exception, but during the course of the test, I tried them both individually with other com-ponents to see how they would fare. They passed with flying colors. b

But wait, this is only a $1300 preamp and that’s the kicker.

©2005 Tone Audio Printed with permission from Tone Publications. All rights reserved.

the audiophile voice00

LOVE THE DUTCH. The best vacation I ever took wasspent, in a large part, in Amsterdam, one of the mostbeautiful cities I have ever visited. The Dutch charactercombines the devotion to precision and “job well done”found in the German and Swiss cultures, but is tem-pered with a sense of practicality and good humor.

The reviews in other publications, both print andonline, of the Primaluna Prologue 1 integrated ampseem to be all raves, and made me eager to hear one oftheir products. Upon learning that the Netherlands-based company had an all-tube preamp at an extremelyaffordable price, I contacted fearless leader Pitts to see ifI could get a unit for review. (That’s “Gene, TheInfeckable” to you and your immediate kin, Driscoll!Emperor Pitts)

Kevin Deal of Upscale Audio was delighted to sendme a preamp, and asked if I wanted a phono stage,which neither Gene nor I knew was an option. Kevinalso suggested that he send along an amp, the Prologue5, which uses KT88 output tubes and develops 36 wattsper channel.

Primaluna’s ads claim quite a lot for their products,such as “build quality the equal of any product at anyprice.” I think you will agree that is a pretty heavy-dutyclaim for such modestly priced gear, I would say. ThePrimaluna gear, designed in the Netherlands and builtin China, is all hand-wired, uses Alps pots, audiophile-grade capacitors from Solen, etc. The design incorpo-rates something called “adaptive auto bias” allowingthe use of, according to the company, unmatched out-

Mike Driscoll

I

PrimalunaPrologue 3 Preamp

and Prologue 5 Amp

put tubes, thus completely eliminating the need for bias-ing the amp. In a phone conversation, Kevin informedme that, although not recommended from a sonic stand-point, the amp could be used with four different outputtubes, such as one EL34, one KT88, one 6L6, and one6550. He claims that the auto bias circuit will automati-cally bias each tube to match the others. He also insist-ed that I remove the bottom covers from the units inorder to check out their build quality, of which he isparticularly proud. He also asked whether I wanted sil-ver or black faceplates. (I chose the silver.) With all thisoffered at a retail price of $1395, I was starting to feellike one of TV’s “Mythbusters,” and was very anxious torun these babies through their paces. And so, it came topass that towards the end of March, two boxes fromUpscale arrived at my door containing a Prologue 3,and a Prologue 5.

The first thing I did was to remove the bottom platesfrom each unit in turn, and admire the constructionquality. These guys aren’t kidding about their stuff beingthe equal of gear costing twice as much or more in thisarea. Hand wired, hand soldered, and with obviouslyhigh quality components. I also was surprised by theheft of these units, they are both solidly built pieces ofequipment. The silver faceplates are a good quarter inchthick (and all true audiophiles are aware of the sonicbenefits of thick faceplates.) The controls have a solidand expensive feel, the paintwork is flawless, at least tothese aging eyes, and (a pet peeve of mine) the poweron-off switches are easily accessible on the left sides ofthe units, towards the front. Although I was riskingbeing late for work that day, I hastily wired the pre andpower amps into my system, so that upon my returnhome, I could settle down and listen immediately.While I was at work, I left the units powered up andplaying Music Choice from Comcast cable, so theywould be warm and ready to go. (I’m sure my catenjoyed the bluegrass music that day.)

Even though Kevin had told me that the phono stageneeded 100 hours or more to sound it’s best, I grabbedan assortment of LP’s and sat down to listen. What Iheard totally changed my perception of the sound quali-ty available for such little money. Even unbroken-in,what I heard blew me away. The first LP on the ‘tablethat night was “Francis A & Edward K, featuring theDuke Ellington orchestra with Frank Sinatra vocals.(Reprise S1024) The orchestra literally filled my listen-

Volume 11, Issue 600

Primaluna Prologue 3 Preamplifier And Prologue5 Amplifier, $1395.00 each. U.S. distributor,Upscale Audio, 2504 Spring Terrace, Upland, CA91784. Phone 909/931-9686, fax 909/985-6968,web site www.upscaleaudio.com, e-mail see website “contact” page.

Associated EquipmentSound Valves VTA70 tube amp, Jolida JD202atube integrated amp, ODL HT-2 solid state amp,B+K Sonata series Pro 10 mc solid-state preamp,Audible Illusions Modulus tube preamp, MirageM3si loudspeakers, Paradigm Atom loudspeakers,VPI HW19jr/AQ PT6/Sumiko BPS turntable andphono cartridge, Denon DVD2900 universal CDplayer, Pioneer Elite DV45a universal CD player,Margules Magenta ADE24 analog-digitalenhancer, Interconnects and cables by Kimber,PNF, JPS, and Audioquest, assorted tweaks, foot-ers, bases, stands, charms, and talismans to driveaway evil audio spirits.

N O T E S

ing space and beyond, with width and depth extendingfarther out and back than I had ever experienced withmy system. Timbre, harmonics, pace, and that famousvoice, front and center, with the orchestra surroundingit. After the first couple of cuts, I recall sitting there,shaking my head, and saying “WOW” over and over. Inoticed no glare, etch, or anything else that would inter-fere with my enjoyment of the Primaluna’s wonderfullyopen top end, and the bass was, even through my mod-erately efficient Mirages, deep, tight, and the antithesisof “muddy.” Kevin had expressed a little concern withthe 86Db efficiency of my speakers, but I found thePrimaluna amp was able to drive them to levels farhigher than those at which I would ever listen with nosense of strain at all. As the units accumulated hoursand began to break in, all I really noticed was more ofthe same, that is, the sound became smoother, sound-stage expanded even more, and “musicality (there’s thatword again) increased along with my admiration forwhat Primaluna had wrought. The phono stage seemedto benefit most from break-in time, the stage opening upeven further, revealing things I had never heard in myLP’s, and proving, at least to me, that the LP is the origi-nal, and still best “high-rez” format.

My listening sessions usually take place in the weehours of the morning, as I am a nurse, and work theswing shift. I return home from work at 11:30 or so, andlisten for a few hours, usually quitting at around 2AM (abenefit of being single, I suppose) With the Primalunagear in the system, I found myself listening further intothe night, one LP or CD leading into another, and thenanother, until finally, I would realize that it was 5AM orso, and I had to go to work the next day. During onememorable session, I had put Elvis Costello’s “All This

Useless Beauty” onto the VPI, which led me toCostello’s “Almost Blue,” his album of country classics.This in turn led into Emmylou Harris, Gram Parsons,Karl Shifflet…on and on. I finally had to quit when Inoticed the sun coming up as I was listening toEmmylou and Mark Knopfler’s new collaboration, “Allthe Roadrunning.” The music and (especially) thesound were just so great; I didn’t want to stop.

Following Kevin’s suggestion that I try out differenttube types in the amp, I pulled the EL34’s out of mySound Valves VTA70, and installed them in thePrologue 5. I wasn’t sure what to expect when the unitwas turned on, but to my relief, there were no fireworks,just beautiful sound. Discretion being the better part ofvalor, I didn’t try the KT88’s in the Sound Valves. Basswas, with the EL34’s, a bit looser, seemingly not quiteas deep. When pushed, there seemed to be a bit of con-gestion on complex classical pieces, which was not sur-prising, considering the slight power drop with thesetubes. The sound was, however, eminently listenable, ifnot quite to the level of the amp with the originalKT88’s.

Do I have any criticisms of the Primaluna pair? Ofthe amp, none. As far as the preamp, I wish it includeda tape monitor circuit; that’s it. I’m keeping this stuff!We’ve all heard of that “point of diminishing returns,”where the amount of money one spends gives less andless improvement in sound quality and satisfaction.That point varies, of course, with each individual audio-phile, depending upon income, listening acuity, and toa rather annoying degree, snob appeal. The Primalunagear should hit that point precisely for many audio-philes with real-world budgets and concerns, like foodand rent. Great job!

the audiophile voice00

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Issue 44£4.50

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R E P R O D U C I N G T H E R E C O R D E D A R T S

8/44

LET ‘EM ROLL

Loudspeakers that dare to be differentValve amps and a bit of solid-stateAnalogue and Digital source components

UK_US COVER 44 17/3/06 15:34 Page 2

98-101 Prima Luna 17/3/06 12:13 Page 98

EQUIPMENT REVIEW

performance. Trouble is, music is not steady-state and predictable!While negative feedback can be used to make a poor amplifier lookgood on paper, it definitely won’tcreate an amp that sounds as good

as it measures.

The Prologue 3pre-amp also runs withoutnegative feedback, and does not havethe usual Cathode Follower outputs –it’s Anode out. It also features tuberectifiers, rather than solid state ones. While the difference on paperbetween the integrated Prologue 2and the separate pre/power Prologue3 and 5 is quite small, the net resultsonically seems to be a noticeablybigger and more holographic musical

presentation, with increased depthand spaciousness.

Like the Prologue 2, the Prologue3 and 5 produce an exceptionally rich tonality. The bottom end is fulland weighty, with an unusually richmid-band and smooth sweet treble.The presentation is distinctly warmand honeyed – the classic way a tube

amp is supposed to sound,but all too rarely does. This may take a littlegetting used to –especially if you’re more

accustomed to listening to tight well-damped

transistor amplifiers – thesonic equivalent of movingfrom Canada to Florida!Once you do get used to it,there’s little doubt as towhich sounds more realand true-to-life. At least

that’s my take on it. You get more of that weighty

woody warmth and bloomon instruments like acoustic

double bass, and the result is very believable. There’s somethingvery inviting and beguiling about thisamplifier. It’s so smooth and refined.Note the beautifully sweet top-endand deliciously liquid mid-range –absolutely gorgeous. In short,extremely clean and effortless, yet not without point or incident.

For all its warmth and refinement,the musical presentation is

The Prima Luna Prologue 3 Pre-amp andPrologue 5 Power Amp

by Jimmy Hughes

It was back in Issue 35 that I reviewedthe Prima Luna Prologue 2 integratedvalve amplifier. And very good it wastoo. I loved its warm lush sound andsmooth mellow richness. Sonically, itwas unmistakeably ‘tube’ in the bestsense of the word, with all that implies.Not only was it an excellent amplifierin terms of sound quality, build, andfinish, it was reasonably priced andvery good value. I really liked it, andwas sad to see it go.

The Prologue 3 pre-amp andPrologue 5 power amp represent the next stage on, so to speak,and (without thinking) I just assumed a two-boxversion would be morepowerful. In actual fact, the difference in specification is not so great. Bothmodels offer around40W per channel, andmore or less similar band-width and distortion figures. The difference is a new Driver andPhase-Splitter circuit, which allowsthe Prologue 5 to operate withoutglobal negative feedback.

Most amplifiers have a degree of negative feedback to help reducedistortion. The idea is to feed back a part of the signal so that additivedistortions are cancelled out. It works superbly well on steady-statepredictable signals (like test tones),and greatly improves measured

99

98-101 Prima Luna 16/3/06 14:01 Page 99

100

actually quite vivid and dynamic, withexcellent attack andimmediacy. As the Prologue2 was no long around, Icouldn’t directly compare itto the Prologue 3 and 5combination. But mysense is that the two-boxamps sound noticeablymore three-dimensionaland holographic. There’sa much greater depth andrange to the sound, with increased width andspaciousness.

Now 40W is not an especially highoutput. But don’t pre-judge thePrologue 5; it actually sounds verygutsy and powerful – as though it hada couple of hundred Watts in reserveand was just idling along. My ImpulseH-1 horns are fairly efficient, but byno means exceptionally so. Yet thePrologue 5 had power in reserve todrive them as hard as I would everwant – or so it seemed. There was thatsense of ease and effortlessness oneassociates with big amplifiers.

And, because the musicalpresentation had such holographicdimensional qualities, voices andinstruments were projected into theroom with a tangibility that didn’trely on muscle alone tocreate a big room-filling effect. Thesound was big andfull-bodied. Even whenplayed quietly themusic had acommanding presenceand energy. Clarity wasexcellent, and so too was pitchdefinition. Even during complexpieces, the Prologue 3 and 5 retainedpoise and control.

Although there’s no more poweravailable, the two-box amp definitelysounds as though it has more inreserve than the Prologue 2. As wellas appearing subjectively morepowerful, the Prologue 3 and 5 also

sounds more delicate – more finelynuanced - with a lovely honeyedrichness that’s very attractive. You canhear these qualities on pretty much alltypes of music.

Of course classical music andnaturally-recorded acoustic jazz areperfectly

served.But so too arerecordings ofelectronically-createdsounds and aggressive brightly-recorded pop albums. With the latter,there’s no lack of brilliance or bite,but at the same time the amplifier - by

not adding its own edge andaggressiveness – helps create animpression of refinement and control.

The Prologue 3 and 5 sound verycivilised without being boring or

bland. The top-end is very wellintegrated with the mid-band, meaning that sourceshave to be really rough and

abrasive to provokeharshness. Yet there’s nosense of things beingartificially smoothed-over or prettied up.Indeed, the opposite is

true – the sound isunusually vibrant and colourful, withvivid detail and brilliant clarity.

Timing is excellent, and there’sgood rhythmic drive and forwardmomentum. I liked the way thePrologue 3 and 5 gave you ‘time’ -time to listen and assimilate themusic. I’m not sure you’d call this afast amplifier; the full bottom endmakes sure that bass lines are

properly weighty sothey really under-pinthe music, as theyshould. This in turncan give theimpression of thingshappening withgreater poise anddeliberation. The ‘speed’ of anamplifier is a

contentious issueanyway, since no one has

ever related measurablethings like transient rise time

with the subjective impression ofthe music moving quickly. In my

experience, the absence of bass is themain thing that creates a (false)impression of speed. Put another way,the Prologue 3 and 5 do not create awelter of fast but unrelated leadingedges that can sound superficiallyimpressive, but soon tires the ear.Presentation is always coherent andintegrated.

EQUIPMENT REVIEW

98-101 Prima Luna 16/3/06 14:02 Page 100

101

The power amp offers a choice of 4 Ohm and 8 Ohm outputs so youcan achieve a good match with yourloudspeakers. The correct matchgives the highest output, but I selected the 4 Ohm optionbecause (with my speakers)this gave a slightly ‘darker’richer tonality, with bettercontrol. You lose a small amount of poweras a result, but this isnot serious. Try bothyourself beforedeciding.

Like the other Prima Lunaamplifiers, the Prologue 3 and 5feature something called Soft Start,which reduces stress to the tubeswhen the amp is first switched on.The circuits do not run to the tubes to the edge, meaning longer tube life and less deterioration over longperiods of use. When the time comes to replace thetubes,

there’s no problem with biasing thanks to something called Adaptive Auto Biasing, whichindividually monitors each tube andmakes the necessary adjustments.

Prima Luna claim the Prologue 3and 5 are unusually quiet in terms of residual noise, and this seems to be the case. While I could just detecta little hum and buzz with my earclose to the speakers when testing the Prologue 2, I could hear nothingwith the Prologue 3 and 5. It seems

to be pin-drop silent – or there-abouts! Problems with residual

noise can be an issue forthose with abnormallyefficient speakers likeLowthers. But on this

showing the Prologue 3and 5 will pass

even this stiff test. Good, afford-

able tubeamps are

becomingsomething

of a Chinesespeciality. This is one I

could certainly see out the rest of my days with. It’s a gorgeous

amplifier that sooths, charms andbeguiles, while stimulating the senses.What’s more important, its qualitiesgrow on you; the more you hear it, the more you like it. There’s never anysense of the amp drawing attention to itself and away from the music.

EQUIPMENT REVIEW

Prologue 3 Pre-amp

Type: Valve rectified,

vacuum tube line-stage

Valve Complement: 2x 12AX7

2x 12AU7

2x 5AR4

Inputs: 4 x single-ended line-level

Input Sensitivity: 200mV

Outputs: 2 x single-ended line-level

1 x single-ended tape out

Output Impedance: 3.5KOhm

Overall Gain: 11.5dB

Dimensions (WxHxD): 280 x 190 x 395mm

Weight: 10.6Kg

Finishes: Black, Silver, Champagne

Price: £1099

Prologue 5 Power Amp

Type: Push-pull, zero-feedback

vacuum tube power amp

Valve Complement: 2x 12AX7

2x 12AU7

4x KT88

Input Sensitivity: 810mV

Input Impedance: 100 KOhms

Power Output: 40 Watts/8 Ohms

Dimensions (WxHxD): 280 x 190 x 395mm

Finishes: Black, Silver, Champagne

Price: £1099

UK Distributor:

Absolute Sounds

Tel. (44)(0)20 8971 3909

Net. www.absolutesounds.com

TECHNICAL SPECIF ICATIONS

The result is natural and real-sounding, yet friendly and

relaxing. It may not be as big a bargain as theintegrated, but it more than justifies the difference

in cost. If you thought the Prologue 2 wasgood, wait until youhear these…

98-101 Prima Luna 16/3/06 14:02 Page 101

6moons audio reviews: PrimaLuna ProLogue 3 & 5

This review page is supported in part by the sponsor whose ad is displayed above

Reviewer: Srajan Ebaen Source: Zanden Audio Model 2000P/5000S Preamp/Integrated: ModWright SWL 9.0SE; Bel Canto Design PRe2; Eastern Electric MiniMax; PrimaLuna Prologue 3 [on review]Amp: First Watt F1; First Watt F 2 [on review]; PrimaLuna Prologue 5 [on review] Speakers: Zu Cable Druid Mk4; Zu Cable Method [on review] Cables: Zanden Audio proprietary I²S digital cable; Stealth Audio Indra; Zu Cable Ibis; Crystal Cable Reference power cords; Z-Cable Reference Cyclone power cords on both powerline conditioner Stands: 1 x Grand Prix Audio Monaco four-tier Powerline conditioning: 2 x Walker Audio Velocitor S Sundry accessories: GPA Formula Carbon/Kevlar shelf for tube amps; GPA Apex footers underneath DAC and amp; Walker Audio SST on all connections; Walker Audio Vivid CD cleaner; Furutech RD-2 CD demagnetizer; WorldPower cryo'd Hubbell and IsoClean wall sockets Room size: 30' w x 18' d x 10' h [sloping ceiling] in long-wall setup in one half, with open adjoining living room for a total of ca.1000 squ.ft floor plan and significant 'active' cubic air volume of essentially the entire (small) house Review component retail: $1,295 for preamp; $1,295 for amp

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Says Herman van den Dungen about his brand name: "In Italian, it of course means First Moon. My grandmother, an aristocratic lady in a small Dutch village, called my grandfather Herman Maantje, meaning Little Moon. The name stuck with the villagers and me." (And for those suspicious of the name's true Italian roots, there is a small town 50 kilometers north of Milano called Primaluna, near Lake Como.) Adds Kevin Deal, PrimaLuna's exclusive US distributor: "Herman is the Benelux importer for Krell, Conrad-Johnson, Sonus Faber and the man behind Ah! Tjoeb, a brand I'd imported from him for a while. For PrimaLuna, Herman commissioned Marcel Croese who was Goldmund's chief engineer and designer. Herman and Dominique bought a house in China and she is learning the language."



"Like them, Marcel is nothing but a perfectionist. We had the first production run of the new preamp ready to roll. Marcel grabs a sample and puts it on the bench. It checks out beautifully as does everything about the way it's built. What does he do? He takes a sensitive heat probe and measures every single part while he's stressing the unit. He discovers one part that runs a bit hotter than he likes. Herman shuts down the entire production and insists the part get changed." "That's why this stuff is as good as it is. There are no shortcuts, no compromises. Our failure rate in the field, of our Component of the Year 2004 in HiFi+, the ProLogue Two integrated? Nada. Zero. Listen, I love selling affordable stuff but not if it breaks. Since we're tube guys and many newbies are gun shy about valves, we insisted that our amps would be self-biased, wouldn't sacrifice parts should a tube go bad and run perfectly with non-matched bottles. And that's exactly what Marcel and Herman have accomplished. As an old veteran in the retail trenches, I had some input into certain features. Make sure you check out how these things are put together. There's nobody in the business right now who can beat us on how well our components are crafted."

Arriving triple-boxed, white gloves and owner's manual in their own foam insert recess, Kevin's enthusiasm translated from the moment the FedEx man left. Inspecting the midnight blue five coats of hand-rubbed (slightly metallic) lacquer and the



flawless fit of all external panels and connectors confirmed it. Looking inside killed a whole flock of birds with one stone. Close-ups anon. The ProLogue 3 is PrimaLuna's dedicated dual-mono, non-inverting tube preamp. It's valve-rectified, can take an optional MM phono board and runs two 12AX7s and 12AU7s each. With the power mains discretely tucked on the left side just behind the silver (or black) fascia, the rear offers four pairs of RCA inputs, one fixed out and two variable outs. Gain is a low 12dB for a superior S/N ratio of 93dB, A-weighted at 775mV. Frequency response is 4Hz - 110kHz +/- 3dB. Input Z is 100kOhm, input sensitivity 150mV, output Z 2.8kOhm. Weight is 23.5 lbs, dimensions are 15.5" x 11" x 7.5" D x Q x H.

Tube rollers can have fun with ECC83/803S, E83CC, 7025, CV4004 and low-gain 5751 in place of the stock 12AX7s; ECC82/802S, E82CC, 5814, 6189 and CV4003 in place of the stock 12AU7s; and GZ34, CV1377, 5V4G, 5T4 and 5Y3 instead of the stock 5AR4 rectifiers. An auto-mute soft-start feature turns the frontal power LED from red to green in about 30 seconds.




The ProLogue 5 is the upscale version of PrimaLuna's two current stand-alone power amplifiers. Non-inverting, it uses the same small tube complement as the preamp but then adds four KT-88s for 36 watts of Class AB push/pull output power over a bandwidth of 4Hz to 110kHz -3dB. Input impedance is 100 kOhm, input sensitivity 600mV, gain 29dB. Net weight is 37.5 lbs, dimensions are identical to the preamp. Ditto for the removable, banana-fitted tube cage.

With 8/4-ohm WBT-style bindings posts and a pair of RCA inputs plus the ubiquitous power IEC, the back is just what you would expect. Under the substantial hood resides a toroidal power transformer and two US-made Marcel co-designed custom output transformers that are fully encapsulated for lowest hum. Nichicon and Solen caps; "super-fast Philips-diode

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circuitry"; soft start; tube plate fuse protection for the output tubes; and Adaptive AutoBias make up the highlights of the innards. Besides constantly monitoring and adjusting the output bias, the proprietary AAB circuit is said to also reduce distortion between 12 and 30 watts by as much as 40%, adding not merely peace of mind but superior audible performance [board below].



Tube rollers are once again encouraged to party just as they were with the preamp. For the power tubes, you here can pick between 6550, KT90, EL34, 6L6CC, 7581A and KT66, sacrificing a bit of output power depending on choice. It's seemingly très chic these days to dumpster-dive for audio oysters - er, haggle for deep discounts. Part of that is our zeitgeist, part of it misplaced rebellion against escalating prices. Why misplaced? Because high-performance value-priced goods are plainly available. Those do not warrant or justify haggling. PrimaLuna's new components are prime examples of this breed.



As Rogue Audio's new Titan series proves, one doesn't have to go off-shore to play in these leagues. Conversely, going offshore is just as viable a solution. In the context of performance reviews, audio writers must judge products solely on their merit to the consumer. We are not to disguise as market analysts to speculate on the long-term economic impact this burgeoning trend predicts for our domestic cottage industry called HighEnd audio. That's what Editorials are good for.

According to a recent reader E-mail, princess Diana's sad death can be viewed as an example for this polyglot trend: "An English princess with an Egyptian boyfriend crashes in a French tunnel, driving a German car with a Dutch engine, driven by a Belgian who was drunk on Scottish whisky (check the bottle before you change the spelling). They are followed closely by Italian paparazzi on Japanese motorcycles and treated by an American doctor using Brazilian medicines. This note is sent to you by an American using Bill Gates' technology and you're probably reading this on your computer with Taiwanese chips and a Korean monitor, assembled by Bangladeshi workers in a Singapore plant, transported by Indian lorry drivers, hijacked by Indonesians, unloaded by Sicilian longshoremen and trucked to you by Mexican illegals..." Listening notes to follow in due course. For now, my visual inspection of these Dutch/Chinese components leaves me clearly impressed. This is smartly executed, fully thought-thru kit at bargain basement tickets for what's on offer. Using an existing Cayin/Spark Audio/Zhuhai Electronics platform for their first product kicked off enthusiastic press reactions from none other than Ken Kessler who considered the ProLogue Two the affordable integrated to beat, displacing the famed Unison Research Unico in his personal pantheon of overachievers. With the new releases of ProLogue 3 through 5 (one preamp, two amplifiers), the brand goes more upscale yet pricing per component remains firmly where it was before. For PrimaLuna acquisitions, international customers will deal with Herman's firm HiFi-Notes in Holland while US punters already know to contact Kevin at Upscale Audio. Added Kevin: "HighEnd audio is shooting itself in the foot like no other industry I can think of. We need transitional product that's reliable, attractive, affordable and offers a serious taste of what we're about. It's the only way to attract new blood. And that's the whole raison d'être for PrimaLuna. It's a brand with a mission. That's why we'll have a few select dealers too so people can see and hear these components for themselves."




The best people to review affordable stuff are, naturally, people who own affordable stuff. They have the proper context to recognize true overachievers. The problem is, some readers don't believe them as much as they believe high-end writer/owners whose context is informed by exposure to the state-of-the-art shit. Say you're one such reviewer of the deep pockets. Do you worry about what other people think? Then reviewing overtly value-oriented high-performance products like PrimaLuna's can cause a few scary reactions. The obvious one is to overwrite as though one were faced with the Second Coming. Since most reviewers have seconds a few times a year, multiply their sightings with the numbers of audio writers working. The name JC suddenly becomes more ubiquitous than the ordinary Joe. To avoid undue hyperbole, many writers pursue the opposite approach. They underwrite. Each and every complimentary observation on the affordable subject is qualified. "But" becomes the omniscient equalizer. It's a subset of the Messianic faith. The Lord giveth, the Lord taketh away. "The Superior Amp does an excellent job of resolving spatial cues but compared to my Reference, it falls short in the rear of the recording venue and is guilty of lateral compression." As a prospective buyer of the Superior Amp, you soon feel cheated. Are you reading about hand-me-downs? It's likely true that the affordable amp isn't the equal of the reviewer's darling. Still, something about a blow-by-blow comparison feels like watching an amateur underdog get beaten to a bloody pulp by a disguised pro. It's no fun. The referee should long since have stepped in and disqualified the match.

Practically speaking, mismatches are nearly par for the course when a reviewer of expensive stuff gets the occasional affordable stuff. Review protocol means you change one component at a time. In that context, whatever the reviewer replaced will have been a lot more expensive and thus, presumably, unfairly superior. Hell, a pair of his interconnects could cost more than the component under review. All this by way of setting the stage for today's contenders in an attempt to neither over- nor underwrite but stay the middle. They've very good for the money. Does that make them giant killers? Not necessarily. Spend more and you can get better. How much more and how much better depends on not just individual components but what speakers you wish to drive, what you listen for and how much you care about particulars. In his review of the Horn Shoppe's Model 1, Stereophile's Art Dudley differentiated between speaker sensitivity and efficiency to make an important point.

Though these terms are interchangeable in common parlance, Dudley differentiated between them to mean decibel output for a given input voltage (sensitivity) and load behavior complexity (efficiency). The latter includes phase angles, back EMF and impedance stability. A nominal 87dB 4-ohm impedance that operates within a +2/-1 window represents a higher efficiency than a nominal 90dB 8-ohm load that includes



1.3 ohms at 40Hz and 50 ohms at 20kHz and adds 120°+ phase angles. This speaker efficiency consideration becomes relevant with affordable amplifiers. Excessively overbuilt power supplies as found in very expensive amplifiers account for what-if scenarios of dastardly loads and high SPLs. While such strapping amps may not necessarily be sonically superior into cushy loads, they absolutely will be when things get rough. Bottom line? To get the best out of an affordable amp, don't mate it to an inefficient speaker the way Art Dudley defined efficiency. 88dB as represented by my Gallo Reference 3s could be gravy whereas a higher-sensitivity humdinger could show up drive limitations and dynamic compression. That's common sense. The PrimaLuna ProLogue 5 is capable of very fine performance if you don't ask it to do what a $6,000 amp of equal output power would manhandle with ease. Don't think big Thiels, Aerials, Magnepans. It's not just power delivery that does the job. It's current delivery, it's capacitive reserves, it's power supply stiffness. That's where more money spent tends to buy more. (Though many people buy far more emergency headroom than they ever need. They waste money where it only makes a theoretical difference, i.e. none that's actually audible in how they use their systems).

With preamps, think on how much gain you need. Buying a 26dB-gain preamp when your 200wpc amp can be driven to full output by 0.38V and your speakers are 94dB sensitive is madness. You'll barely be able to open the volume pot before your system screams at you. (Gain is defined as a given ratio between input and output voltage. That's just like a fixed multiplier. Put in x, multiply by z to get your output voltage. A hi-gain device has a higher "z".) The ProLogue 3 is a low-gain 12dB design of extremely low noise (something that's very hard to do with hi-gain tube designs). It's perfectly matched to the ProLogue 4 and 5 amps and suitable even in the context of high-efficiency systems precisely because of its low gain structure and excellent S/N performance. As delivered with the stock tubes, the Logue 3's on the slightly soft and somewhat ephemeral/airy side when compared to my hard-driving 5687-fitted ModWright. The options to tube-roll 12AX/AU7s are astronomical. With Kevin Deal the king of tube rollers, I'd have to assume quite a window of sonic variability with this PrimaLuna pre. As with the amp, the following comments will thus concern themselves solely over the stock tubes. We'll get baseline pronouncements for these components' core signatures. You keep in mind that minor cosmetic surgery is readily available. Swap valves for Angelina Jolie lips, a sharper chin or whatever minor alteration you favor. The rest is intrinsic to circuit genetics. Onward ho.

Of the two PrimaLunas, it's the preamp that will surprise most punters. We've all become a bit inured to high-performance affordable valve amps or integrateds. That attitude stems from the oft-recited belief that it's really hard to bollocks up the sound of a tube amp (though making a truly great one is a separate matter). But how often have you come across a truly noteworthy valve pre around the +/- $1,000 mark? The last one in recent memory was the Eastern Electric MiniMax. As a low-gain design, the ProLogue 3 is quieter -- very quiet in fact -- something hi-eff users will appreciate. As a dual-mono design, separation down the middle way back into the soundstage is even better. Likely due to the 12AX/AU7 tube choices, visibility deep into the soundstage and the little details that paint the space is very good. Vocal lock -- that extreme palpability or heightened contrast -- is less than the MiniMax whose color temperature is higher and whose 3D grip is harder.

Texturally, the ProLogue 3 is more neutral than overt tube. However, it's airiness and smoothness even in the face of edgy and non-pretty music like Ivo Papasov's glue-sniffing Orpheus Ascending [Hannibal 1346] with the occasional mike overload and clarinet shrieks could nearly be mistaken for a texture of silkiness. I don't hear it as additive behavior at all but simply a very welcome absence of grit or grunge. Where I do suspect just a skoch of subtractive action is in the minor softening of transients which the more expensive ModWright doesn't smooth over. What's most impressive about the ProLogue 3? It doesn't veil, thicken or slow things down. It's slightly soft but not at all boring or trite. It releases the innate energy of music rather than restrain or interpret it. It has far more than just respectable resolution while



giving you the organic sense of things hanging together properly. Outside of consideration about tone, that's perhaps the most addictive aspect of valves for those who fancy these characteristics. When I think "affordable tube preamp", I usually think slightly noisy, guilty of obscuring fine detail, pretty rather than accurate and possibly truncated in the frequency extremes. This Dutch/Chinese effort sidesteps all of these preconceptions. In fact, I don't believe it commits any errors. The power supply is clearly buff enough to throw one of those colossal and solid soundstages we often equate with stacked reserves. What the Three doesn't do is the full-blown treatment of timbral enhancements and body shaping one can get from octals. My SWL 9.0SE doesn't, either (though it has more apparent drive). That's why I bought it. I want tone but not at the expense of raw data. I get tone squared from the paper drivers of the Druids. The 2nd-order character and transconductance muscle of Nelson Pass' FirstWatt F2 merely adds to the fun. What I'm then looking for in a preamp is dynamics, treble elegance (not attenuation) and spatial magic. Those are all items the PrimaLuna delivers. Turning off the Method sub to check for bass grunt, I thought the ModWright had the upper hand but not by all that much. During climatic swells, I never felt the PrimaLuna prematurely hopped on a smaller wave instead of waiting for the monster breaker I knew was coming.



Is the PrimaLuna suavé - you know, that ineffable quality we admire with certain very expensive valve pres? This is where reality intrudes. For that, you have to spend a lot more. Some folks call it elegance or silk. Others use continuousness or some other hard-to-define term. Even for all that, you have to be lucky enough so it manifests fully, in the context of your personal system and to deliver on the extra money spent for it. It's no surprise that more remains possible past the ProLogue 3. What is a surprise? How big of a step this $1,295 piece makes to get you there. What's ultimately left below the table becomes theoretical and abstract. What's served up is darn convincing. In conceptual parlance, that's called balance. It accounts for the big picture with a limited budget. Without comparisons and a dorky level of critical acuity, you buy into the picture that is presented as is. Balance is a sign of engineering excellence. It's also a bane for reviewers. It's easier to report on violations of balance -- and perhaps more interesting to read about -- than to not find anything that sticks out to become the key mark of character. The MiniMax has more character but a bit less resolution. Readers who own it have shared what preamps the little guy from Hong Kong replaced in their rigs. Since it's second-hand hearsay, I won't divulge brand or model names except to say, some of the items sold (or decided against in favor of the mini) were 5 x as much. Considering the ProLogue's equivalent advantage of offshore manufacture, all of us can comfortably tally up a long list of direct domestic or Euro competitors at double and triple its price. That's plain going into this game. The question remained, would the PrimaLuna suffer any you-get-what-you-pay-for shortcomings? Clearly not. One of the smartest things its designer did was opting for a low-gain architecture. It solves a number of common tube preamp problems - high noise floor coupled to very limited practical volume range. Hand in hand with that decision is forsaking the last words in body or heft. Though likely a generality, high-gain preamplifiers like the Audiopax Model 5 often have higher mass and density. Let's next listen to the Prologue 5 as driven from my customary ModWright to only alter one variable at a time.

Unlike the 35wpc Onix/Melody SP3 integrated, the ProLogue 5 into 101dB speakers proved noisy. Steady-state power supply drone was readily audible in the listening seat when the refrigerator in the kitchen cycled off. Of course, nobody in their right mind would acquire an affordable 40-watt tube amp and drive ultra-efficiency speakers with it. For that, you'd pick a 6-watt Almarro, Decware, Fi or Yamamoto specifically bred for low noise. I'd transition to the 88dB Gallo Ref 3s to be fair to the PrimaLuna. But first, an interesting aside. FirstWatt's F1 and F2 (the two finned and stacked black boxes above) are in an entirely different class of drive, control and subsequent articulation and energy despite being a mere 10 and 5 watts respectively and not designed for conventional speakers at all. I'm not usually fond of the sonics of 200-watt monster amps that keep doubling power down into 1 ohm. However, these transconductance amps have made me come to appreciate the merit of tightfisted control (which muscle amps into the usual loads achieve with massive power supplies, silly current capabilities and kilowatt outputs). Current drive acts like those über amps. Alas, as implemented by Mr. Pass, current drive pursues ultimate simplicity rather than complex multi-stage endlessly paralleled architectures. What's control sound like? More bounce and rebound. More tension and vitality. More projection power of the encoded energy. More bass definition, extension and leading-edge jump factor. As a result of all that, more clarity, immediacy and intensity as though one's attention had just moved forward multiple rows to be closer to a charismatic presenter. Of course, the FirstWatt amps are specialty products. Nothing really compares to them. Consider this a mere foot note then,



of rhetorical value to all but the few who'll ever experience a transconductance audio amplifier. But it is informative for what the PrimaLuna amp can't do. With the Gallos, it was in its native metier, i.e. the kind of speaker a prospective buyer would own or consider. Without the benefit of the Zu Method sub, I found the sound somewhat upshifted. The center was in the upper rather than lower midrange as with the Druids. This was partially due to the Gallo's ultra-dynamic tweeter. Still, even after getting readjusted to the CDT in this system, the Dutch amp still struck me as on the slightly lit-up end of the spectrum. Bass was good but not great (and the Gallos are capable of phenomenal bass if fed a current-rich diet). Occasionally, I even veered into glitters of brightness. That's something my rig usually is never guilty of. Time to go Dutch all the way and find out whether the ModWright wasn't simpatico.

Clearly, the Modright/PrimaLuna combo wasn't a happy one. The, - er full moon combo instantly resolved those issues. It sounded as though someone had just turned down the treble and sharpness controls back to default. I have no explanation for why or how but occasional weirdnesses do happen. This now was highly enjoyable music making. It had the Gallos sound again like the reason I bought 'em for in the first place. However, bass reach still wasn't what it could be nor was bass control spectacular - good but not the reason you'd buy this combo for these speakers. Rather than serve as foundation, the bass became accompaniment. It made vocals instead of bass the foundation of sung fare. It was a slight weighting or shift in prominence, not through unduly highlighting voices in deep-triode fashion but by being a bit less than endowed in the lower octaves. Clearly, the ProLogue 5 is designed to sound good but not to simultaneously act as pile driver. Unfortunately, I didn't have another conventional speaker on hand whose bass system is a less current-happy affair than the Reference 3s. The minor softening action of the Prologue 3 translated intact through the ProLogue 5. This gear isn't flat-earth PRat focused. It's more about flow, color and mellifluousness - round earth.

As with the preamp itself, I was once again mightily impressed by the amount of fine inner detail retrieved. Remember, this is affordable gear. To boot, it will be sold through a few select dealers. Do the math. We're dealing with gear that by necessity needs to compromise somewhere. The question is simply where. I'd say here it's a conscious choice of finesse over brawn. Even into easier loads like the Gallos -- easy except for the full glory of those 10-inchers -- you'll subtract a certain amount of heat, pressure, energy and focus compared to more expensive gear that'll sport more pronounced transients and even heftier power supplies for more tension inside the tunes. The flip side? By forgoing the muscle-bound route of oomphosity, we add sophistication and sheer listenability over most all kit that's priced transitionally, i.e. as stepping stones from receiver land into high-brow separates. The designer of PrimaLuna clearly used his test bench. He insisted on wide bandwidth linearity and low distortion into reasonable loads. Nothing here suggests interpretative contouring, darkness or vintage-style voicing. Musical minutiae you know from romps with expensive stuff aren't obscured or blotted out. The soundstage doesn't shrink. You don't run out of volume. Things don't get ugly or hairy. It's simply that the scale of intensity reduces somewhat. Think a version of reality that's a bit lighter in the loafers than the heavy-duty stuff, whose excitement level is a bit more relaxed. Let me put it another way. This isn't wannabe gear struggling upwards from below but never fully emerging into the light. This is gear that's trickling down from above (in this case precedents set by Goldmund, experience and high-level engineering). It dilutes certain



things just enough to get the price into the target range. It doesn't throw things out by claiming them inaudible as MP3 compression does. Instead, it backs off slightly on the throttle. In automobile terms, you're not going as fast and the wind doesn't blow as hard in your face but the scenery is all the same. (The SP3 integrated has superior drive and apparently more iron under its covers.)

The way it sounds to me from listening to the PrimaLunas? They're just what its people claim they aimed for during their development phase: Components that provide an attractive entry into the world of -- tubed -- HighEnd Audio. They are smartly positioned close to where the road of diminishing returns skirts off into the hinterlands. Nothing about appearance and build quality suggests anything other than high class. The -- relative -- limitations here (and really mostly with the amp rather than preamp) will materialize as you choose less and less friendly speaker loads. A smart match for example would be a Triangle floorstander. Its fast and dynamic nature makes it a natural complement to the fine-boned nimble mien of the Dutch. The feature set except for a lacking remote is comprehensive and especially the second pre-out is welcome for subwoofer or bi-amp applications. The preamp wouldn't be out of place mated to amplifiers rather more expensive than its siblings. Reliability -- and the requisite service support for those what-if occurrences -- as well as actual inventories all seem to be in place well before a full-blown marketing campaign and dealer network formation have ever been pursued. These are all excellent signs for how to do things right. I call 'em vital ingredients that go well beyond just how something sounds. So let's tally up: Excellent packaging and comprehensive support literature. Great looks in two fascia color options. Set'n'forget fun with valves. Tube rolling encouraged and not expensive. Real-world power and features. Modern high-resolution sound. If perhaps a touch polite, surely the preferred direction to err in when it comes to the real world with the music played in it. No overt shortcomings that would limit use (except the non-issue of amplifier power supply noise into ultra-efficient speakers that don't even come close to needing its 40 watts). Strong points? The very low noise floor of the lo-gain preamplifier, making it copasetic into truly hi-rez systems, high-sensitivity speakers and beaucoup-gain amps. Final verdict? For once, we have truth in advertising or promotional propaganda. Eastern Electric's MiniMax quartet and Onix/Melody's SP3 have just gained reinforcement in the sparse camp of bona fide value-priced high-performance kit that uses tubes and isn't accompanied by a long list of conditions that have to be met before you can enjoy. Even if your budget could double their respective costs, PrimaLuna's first separates belong on your shortlist. They'll surely be on mine when readers ask me for glow-in-the-dark recos. Kudos to Messrs. van den Dungen, Croese and Deal. They combined their various talents and resources to give "entry-level" music lovers a reason to come into our church and get more than just a tacky call to pitch into the collection plate. This is stuff you'd feel comfortable recommending to family members - you know, groove lovers who enjoy good music but couldn't -- and shouldn't -- be bothered with audiophile catch phrases and geeky tech talk. Just show 'em where the 'on' buttons are and the volume control. The rest speaks for itself. That's what affordable audio should be all about. That's exactly what the PrimaLuna ProLogue 3 and 5 are. I wouldn't call them giant killers but simply, very good values. That's more honest, realistic and believable and just what the world needed (said without the usual sly grin that you were just being facetious.)


ProLogue Three & Seven Reviews

www.Stereophile.com, December 2006 119

Everybody loves a bargain. No—make that: Most people love a bargain.Some just want the best, and they don’t care about the cost. Some evendistrust and reject out of hand any product that’s not expensive enough. Ifyou’re one of these people, you might as well stop reading this reviewright now—the PrimaLuna ProLogue Three and ProLogue Seven are notfor you. $1395 for a tube preamp? $2695 for a pair of 70Wpc tubemonoblocks equipped with four KT88 tubes each? Must be based on old

designs in the public domain using cheap parts carelessly assembled…But in fact—and putting sound quality aside for the moment—these PrimaLuna prod-

ucts are serious, well-thought-out designs of considerable originality, in which arefound such high-quality parts as Solen capacitors, Alps potentiometers, and fast-recov-ery diodes. The ProLogue Three and ProLogue Seven are claimed to have been madewith “workmanship equal to or better than any product that you can buy at any price,period,” and I’m not about to refute that claim.

As for the sound…well, I’ll get to that shortly.

Some backgroundPrimaLuna products represent true international cooperation. The company wasfounded by Herman van den Dungen, a high-end audio distributor in the Netherlands;

PrimaLunaProLogue Three & SevenTUBE PREAMPLIFIER & MONOBLOCK AMPLIFIER

E Q U I P M E N T R E P O R T

Robert Deutsch

PrimaLuna ProLogue Three & Seven tube preamplifier & monoblock amplifier

PROLOGUE THREE Tube line-stagepreamplifier. Tube complement: two5AR4, two 12AX7, two 12AU7. Maxi-mum gain: 12dB. Frequencyresponse: 4Hz–110kHz, ±3dB. THD:<0.2% at 775mV RMS output. Sig-nal/noise: >93dB(A) ref. 775mV.Input impedance: 110k ohms. Out-put impedance: 2800 ohms. Powerconsumption: 46W.WEIGHT 23.5 lbs (10.7kg).SERIAL NUMBER OF UNITREVIEWED 05060314.PRICE $1395.PROLOGUE SEVEN Tube monoblockpower amplifier. Tube complement:four KT88, two 12AX7, two 12AU7.Power output: 70W (18.45dBW). Fre-quency response: 20Hz–85kHz,±1dB at rated power; 11Hz–120kHz,–3dB at 1W. THD: <0.1% at 1W,10W; 1.5% at rated power into resis-tive load. Signal/noise: 101dB. Maxi-mum gain: 28.5dB. Power consump-tion: 125W at idle, 225W at ratedmaximum power.WEIGHT 37.5 lbs (17kg).SERIAL NUMBERS OF UNITSREVIEWED 05100043, 05100044.PRICE $2695/pair.BOTHDIMENSIONS Each: 11" (280mm)W by 7.5" (190mm) H by 15.5"(400mm) D. WARRANTY 2 yearslimited, 6 months on stock tubes.Approximate number of dealers:Sold direct.MANUFACTURER Dorob Audio BV,P.O. Box 109, 5250 AC Vlijmen, TheNetherlands. Web:www.primaluna.nl. US distributor:Upscale Audio, 2504 Spring Terrace,Upland, CA 91784. Tel: (909) 931-9686. Fax: (909) 985-6968. Web:www.upscaleaudio.com.

the designer is Marcel Croese, who heldthat position with Goldmund in Switzer-land. The products are made in the Peo-ple’s Republic of China (at these prices,did you think they’d be Swiss-made?).International marketing and liaison withthe Chinese manufacturing facility is han-dled by Dominique Chenet, who hailsfrom France, where she worked for Jadis.US distribution is by Kevin Deal ofUpscale Audio, known in some quartersas the “tube guru.”

As Herman van den Dungen tells thestory, his grandfather, also named Her-man, was given the nickname “Maontje,”

which means “Little Moon” in Dutch, byhis wife, and that’s also now the name ofvan den Dungen’s little dog. Herman’sfather’s name was Cor, so he is called“Herman from Cor from Maontje vanden Dungen.” And so—I hope you’re fol-lowing all this—“that’s why I thought ofFirst Moon as a brand name.”

And why an Italian name? Well, that’snot really explained, except to say thatthere is a small town near Lake Comocalled Primaluna—but it has nothing to dowith the audio business. My theory is thatHerman van den Dungen just liked thesound of PrimaLuna, which does roll off

the tongue in a very musical way.

Description and designThe ProLogue Three and ProLogueSeven share certain characteristics.They’re exactly the same size and arebuilt by hand with point-to-point wiring;the fully vented chassis are of heavy-gauge steel with five coats of finish, eachcoat hand-rubbed and polished. Premiumparts are used throughout; supplier namesinclude Alps, Nichicon, Solen, Swellong,and WBT. The ProLogue Three andSeven both have a SoftStart circuit toextend the life of components and reduce

120 www.Stereophile.com, December 2006

M E A S U R E M E N TS

The Prologue Three’s maximum gain was to specifi-cation at 12.2dB, and the preamplifier preservedabsolute polarity; ie, it was noninverting. The inputimpedance was usefully high, at around 100k

ohms in the bass and midrange. It dropped, slightly butinconsequentially, to 77k ohms at 20kHz. The outputimpedance was also to specification in the midrange andtreble at 2.7k ohms, which is higher than usual, but roseto a high figure of 11.5k ohms at 20Hz. This preamplifierreally does need to be used with an amplifier having aninput of 50k ohms or more if the bass is not to soundlightweight. At 77k ohms, the Prologue Seven’s inputimpedance will be sufficiently high, I feel. DC offset wasnegligible.

The Prologue Three’s frequency response didn’t vary atall at high frequencies at different volume-control settings,but did extend a little lower in frequency—0.5dB down at12Hz set to unity gain (2 o’clock) compared with –0.5dBat 20Hz at maximum volume. But as fig.1 shows, thehigh-frequency bandwidth increased significantly into lowimpedances. Note the premature low-frequency rolloffinto the unrealistically low 600 ohm load in this graph,but also the excellent channel matching, which wasequally good at other volume settings. Channel separa-tion (fig.2) was good in the bass and midrange, at 69dB

L–R and 77dB R–L, but worsened above that region dueto the usual capacitive coupling.

With the volume control full but the input short-circuit-ed, the Prologue Three’s wideband, unweightedsignal/noise ratio was a good 68.8dB, improving to 78.4dBwhen the measurement was restricted to the audioband,and to 94.7dB when A-weighted. Fig.3 plots theTHD+noise percentage against output voltage into 100kohms, 10k ohms, and 1k ohm. Into the higher imped-

Fig.1 Prima Luna Prologue Three, volume control at maximum, frequencyresponse at 1V into (from top to bottom at 100Hz, bottom to top at100kHz): 100k, 600 ohms (0.5dB/vertical div., right channel dashed).

Fig.2 Prima Luna Prologue Three, channel separation (10dB/vertical div.).

Fig.3 Prima Luna Prologue Three, THD+N (%) vs 1kHz output voltage into(from bottom to top at 1V): 100k, 10k, 1k ohms.

thermal shock, and there’s a removableprotective metal cage that fits over thetube compartment. I kept these on for allmy listening.

The ProLogue Three is a dual-monodesign, with separate toroidal transformersfor the left and right channels. Two 5AR4tubes are used for rectification; there is noloop negative feedback or cathode follow-ers. The ProLogue Three uses a choke-regulated power supply and DC tubeheaters, which is said to make it less pickyabout tube choices. The ProLogue Threesports four sets of line-level inputs, one ofthem optionally convertible to an internal

moving-magnet photo stage ($159). Thereare two sets of main outputs—a useful fea-ture when you want to add a supplemen-tal subwoofer and don’t want the signalfor the main amplifiers to go through anysort of crossover or switches. Controls arein the minimalist tradition of source selec-tion and volume—that’s it. There is no bal-ance control, no mute switch. The powerswitch is on the left side of the chassis, nearthe front.

The ProLogue Seven, at the top of Pri-maLuna’s amplifier line, produces a max-imum output of 70W. Its circuitry is “clas-sic ultralinear,” with dual-feedback topol-

ogy: cross-coupled current feedback forgain stability, then an additional smallamount of negative feedback to obtainlow distortion and low output imped-ance. This design is claimed to produce allthe benefits of feedback without any of itsdrawbacks. An interesting feature of theSeven is that, in addition to the suppliedKT88s, it accepts a wide range of othertubes as well, including EL34, 6L6GC,7581A, and KT66, the power outputdropping slightly when using any of thesetubes. This flexibility is made possible bythe action of a circuit called AdaptiveAutoBias, which monitors bias, adjusting


P R I M A L U N A P R O L O G U E

ances, the actual distortion starts to rise out of the noise ata few hundred millivolts, and rises linearly with voltage, notactually clipping as such until well above the 1% THDmark, which is our usual definition of clipping. The outputvoltage into sensible loads at 1% THD was >5V, well abovethat required to drive the Prologue Seven to its maximumpower. Into 1k ohm, however, the output voltage was sig-nificantly restricted and the distortion high, again suggest-ing that the Prologue Three needs to be used with poweramplifiers having a high input impedance.

At 1V output, the THD+N percentage remained around0.2% into various loads, though the preamp was a littleless happy driving low frequencies into low impedances(fig.4), this presumably associated with the LF rolloff.However, even into the 8k ohms input impedance of theMiller Analyzer, the distortion was predominantly second-and third-harmonic in nature (fig.5), which will tend to besubjectively benign. And even into this low impedance,the Prologue Three didn’t do too badly on the high-fre-quency intermodulation test (fig.6), the difference compo-nent at 1kHz rising to –60dB (0.1%). This test was takenat 1V output, about the maximum level the preamp likedto put out with this demanding signal.

The input impedance of the Prologue Sevenmonoblock amplifier (fitted with KT88 output tubes, as

noted above) was 77k ohms in the bass and midrange,this dropping to 53k ohms at 20kHz. The Seven was non-inverting from all output transformer taps, and the voltagegain into 8 ohms was 27.2dB from the 8 ohm tap, 26.5dBfrom the 4 ohm tap, and 25dB from the 2 ohm tap.

The Prologue Seven’s output impedance was extremelyhigh from the 8 ohm tap, at 8.5 ohms at treble andmidrange frequencies, and rising to 9.1 ohms at 20Hz. It

Fig.4 Prima Luna Prologue Three, THD+N (%) vs frequency at 1V into (frombottom to top): 100k, 10k, 1k ohms (right channel dashed into 100kohms only).

Fig.5 Prima Luna Prologue Three, spectrum of 1kHz sinewave, DC–10kHz, at1V into 8k ohms (linear frequency scale).

Fig.6 Prima Luna Prologue Three, HF intermodulation spectrum, DC–24kHz,19+20kHz at 1V peak into 8k ohms (linear frequency scale).

it as necessary to reduce distortion and tocompensate for tube aging. Kevin Dealsent me a set of EL34s to try in additionto the stock KT88s.

There are separate output terminals forspeakers with impedances of 2, 4, or 8ohms. My Avantgarde Acoustic Unos arean easy load, their impedance hardly dip-ping below 8 ohms, so that was the set-ting I used. Like the ProLogue Three, theProLogue Seven’s power switch is on theleft side, near the front, which is moreconvenient than having a switch on therear panel, as some other amps do.

Examining the ProLogue Three andSeven, I was impressed with the quality oftheir construction and the general presen-tation. Nothing ostentatious, no sense that

a major part of the cost was spent on flashyindustrial design—just an understated feelof quality, with no rough edges or poorlyfitted bolts. The package includes a pair ofwhite gloves for handling the tubes and toprevent fingerprint smudges on the finish.

SoundAs is my practice, my initial listening tothe PrimaLunas was informal: I pluggedthem in, made the appropriate connec-tions, ensured that everything worked,and started playing CDs. At this earlystage, I try not to be analytical or critical inany way; after all, the equipment mayneed some breaking in before reaching itspotential, so it would be unfair to evaluateit at this point. It also might need some

tweaking to optimize the sound quality.So I just listened to the music. As it turnedout, in addition to my Avantgarde Unos, Ihad on hand two pairs of speakers to bereviewed: the Silverline Audio Preludesand the Fujitsu Eclipse TD-712zs. They,too, were in need of break-in, so I spentsome time listening to them as well.

As much as I try to put any critical atti-tude aside in this sort of informal listen-ing, I can’t avoid forming some impres-sions, and it quickly became apparent thatI was dealing with some very good com-ponents. Determining exactly how good,as well as evaluating the respective contri-butions to the sound of preamp andamps, would take some analytical listen-ing and comparisons with other compo-



m e a s u r e m e n t s , c o n t i n u e d

was around 4.5 ohms from the 4 ohm tap, and still 2.6ohms from the 2 ohm tap. These impedances will maxi-mize power transfer into loads that equal the transformer-tap rating, but will introduce large variations in frequencyresponse with real-word loudspeakers. Into our standardsimulated loudspeaker, for example, there were ±2.2dBvariations in response from the 4 ohm tap (fig.7), rising to±3dB variations from the 8 ohm tap (not shown), andeven ±1.6dB changes from the 2 ohm tap (not shown).

Also apparent in this graph is the amplifier’s very widesmall-signal bandwidth: low frequencies that are flat to20Hz and ultrasonic frequencies that are not down 3dBuntil 110kHz. Though there is the start of some parasiticpeaking evident, this doesn’t reach its maximum untilabove the 200kHz limit of my measurement. Other thanits high secondary impedance, the Prologue Seven’s out-put transformer is obviously an impressive component.Note the excellent shape of the 1kHz squarewave (fig.8),and that while the ultrasonic resonance results in someovershoot, the 10kHz squarewave (fig.9) reveals that theringing is relatively mild.

The unweighted, wideband S/N ratio (ref. 2.83V into 8

ohms with the input shorted) depended on the trans-former tap used, ranging from 85dB (8 ohm tap) through87.1dB (4 ohm tap) to 88.7dB (2 ohm tap). These aregood figures, and the Prima Luna amplifiers did not seemsensitive to grounding issues (though I must admit I didn’t

Fig.7 Prima Luna Prologue Seven, 4 ohm tap, frequency response at 2.83Vinto (from top to bottom at 2kHz): simulated loudspeaker load, 8, 4, 2ohms (0.5dB/vertical div.).

Fig.8 Prima Luna Prologue Seven, 8 ohm tap, small-signal 1kHz squarewaveinto 8 ohms.

Fig.9 Prima Luna Prologue Seven, 8 ohm tap, small-signal 10kHzsquarewave into 8 ohms.

nents—but I already knew that this wasgoing to be anything but a chore.

Before trying any new component, Ilike to “calibrate my ears” by listening tomy usual system: CAT SL-1 Ultimatepreamp, Audiopax Model Eighty Eightmonoblocks (reviewed in the May 2003issue, now in Mk.II configuration), andAvantgarde Uno 3.0 speakers. Apart froma remnant of horn coloration, this systemhas almost everything: a fundamentallyneutral tonal balance (excellent bassextension obtained with its powered sub-woofers), natural-sounding harmonics,great dynamics, and precise imaging. Notas good as the sounds of real instrumentsand voices, mind you, but a pretty goodfacsimile thereof. I also make it a practiceto use familiar recordings, some of themaudiophile favorites and others classics(though not necessarily classical). Thesemay be boring to talk about (and some-

times to listen to), but for me they havethe great advantage of being highly famil-iar; I’ve heard them many times in a vari-ety of systems, so I have a good idea ofwhat they can sound like with differentpieces of equipment. (Having directexperience with making the recordings,as John Atkinson does, would be evenbetter, but not all of us are that fortunate.)

It seemed logical to begin by compar-ing the ProLogue Three preamp with theCAT SL-1 Ultimate, keeping theAudiopax amps in the system. In evaluat-ing preamps and power amps, I always dosome matched-level comparisons, whichin this case was complicated by the factthat the CAT preamp has a switched-resistor volume control with fairly largesteps. What I did was to set the CAT’svolume at a moderate level, measure thevoltage at the amplifier speaker terminalswhen playing the 1000Hz tone on Stereo-

phile’s original Test CD (StereophileSTPH-002-2), and set the ProLogueThree’s continuously variable volumecontrol to match the CAT’s as closely aspossible, which was just slightly greaterthan ±0.1dB.

Changing over from the CAT to theProLogue Three, the first thing I noticedwas that the sound was slightly softer,with the mid- to high treble less promi-nent—not muffled or rolled off in anyobvious way, just somewhat on the laid-back side. The subtle percussive soundson track 3 of the Chesky Records Jazz Sam-pler & Audiophile Test Compact Disc, Vol.1(Chesky JD37) had a crispness as well asdelicacy, but they had just a bit more in-the-room presence when reproducedthrough the CAT. In other respects, thesound of the ProLogue Three was whatI’d call “typically tubelike,” which to memeans smooth, open, transparent, with an



use the preamp and power amps together, as BobDeutsch did, which was when he got some ground-loopbuzz; I should also note that Bob’s Avantgarde speakersuse powered subwoofers, which introduces anothergrounding variable into the mix).

With its low negative feedback, it was not surprising tofind that the distortion present in the Seven’s output roselinearly with output power into all loads, whether themeasurement was taken from the 8 ohm tap (fig.10), the4 ohm tap (fig.11), or the 2 ohm tap (fig.12). But provid-ed the load impedance was equal to or greater than thenominal transformer tap, the distortion can be seen to berespectably low at powers below a few watts. The actual“knees” in these graphs’ traces, where true waveform clip-ping actually begins to occur, are all above our usual 1%THD definition of clipping. But even at 1% THD the Pro-logue gets close to its specified power, provided the loadis twice the tap rating. For example, it delivers 58W into

Fig.10 Prima Luna Prologue Seven, 8 ohm tap, distortion (%) vs 1kHzcontinuous output power into (from bottom to top at 10W): 16, 8, 4, 2ohms.



easy-on-the-ears quality that does notexaggerate, and may even attenuate,harshness in the source material. Com-pared to the CAT, there was someenhancement of midbass warmth thatwould be welcome in a system that tendstoward leanness.

Did I say “typically tubelike”? Audito-ry memory is notoriously unreliable, butthe ProLogue Three reminded me ofthe first tube preamp I owned, a Con-rad-Johnson PV-2ar, which sounded somuch more like music than thesqueaky-clean solid-state unit with DC-to-light frequency response that itreplaced in my system. I’ve heard someexcellent-sounding solid-state preampssince then (the latest being the preampsection of the PS Audio GCC-100,which I reviewed in the January 2006issue), but every time I listen to a tubepreamp I’m drawn into that warm,

engaging presentation that somehowputs the emphasis on the music ratherthan on the technology used to repro-duce it. The ProLogue Three had thisquality in spades.

Was the ProLogue Three as good asthe CAT? No. The CAT combines thismusical quality with a higher level of res-olution, greater three-dimensionality ofsoundstage, and a sense of greater exten-sion at the top and bottom of the frequen-cy range. It also costs more than fourtimes the price of the ProLogue Three.For $1395, the ProLogue Three turned inan outstandingly good performance.

If the ProLogue Three represents anexcellent buy—and it does—the same can besaid of the ProLogue Seven—doubled. Infact, somehow, the limitations of the Pro-Logue Three’s performance in compari-son with the CAT SL-1 Ultimate weremuch less in evidence when it was paired

with the ProLogue Sevens rather than theAudiopax Eighty Eights. There really issomething to this synergy business…

That is, once I’d managed to deal with anasty ground-loop buzz/hum thatappeared as soon as I connected the Pro-Logue Three to the ProLogue Seven. Thishad not shown up when I was comparingpreamps using the Audiopax amps, butthat didn’t necessarily mean there wasanything wrong with the PrimaLunaamps. In my experience, ground loopsoften involve idiosyncratic interactionsbetween components, and floating thegrounds of the ProLogue Sevens (theusual solution to a ground-loop problem)didn’t get rid of the noise, which wouldsuggest that the amps were not at fault.What did work was floating the groundsof all the components in the system,which completely eliminated the prob-lem. The ProLogue Three-Seven combi-



16 ohms from the 8 ohm tap (20.65dBW), 57.2W into 8ohms from the 4 ohm tap (17.6dBW), and 50W into 4ohms from the 2 ohm tap (14dBW). It will deliver the full70W (18.45dBW) into a matched load only if the clippingcriterion is relaxed to 3% THD.

The low distortion into higher impedances was main-tained across quite a wide bandwidth (fig.13), thoughsome rise in THD can be seen in the very low bass and atultrasonic frequencies. Fig.13 shows the behavior from the4 ohm tap; the distortion was a little higher at all frequen-cies into all loads from the 8 ohm tap (not shown), a littlelower from the 2 ohm tap (not shown).

Like the Prologue Three preamplifier’s, the PrologueSeven’s distortion at small-signal levels is heavily second-order (fig.14), though some higher-order harmonics can beseen at very low levels (fig.15). All the harmonics rise in levelas the output power increases, and with the 4 ohm tapdelivering 20W into 8 ohms (fig.16), the second harmoniclies at –48dB (0.4%). In addition, some sidebands at

Fig.13 Prima Luna Prologue Seven, 4 ohm tap, THD+N (%) vs frequency at2.83V into (from bottom to top): 16, 8, 4, 2 ohms.

Fig.14 Prima Luna Prologue Seven, 8 ohm tap, 1kHz waveform at 1W into 8ohms (top), 0.22% THD+N; distortion and noise waveform withfundamental notched out (bottom, not to scale).

Fig.15 Prima Luna Prologue Seven, 4 ohm tap, spectrum of 1kHz sinewave,DC–10kHz, at 1W into 8 ohms (linear frequency scale).

nation was quite sensitive to interconnects,with the lowest noise level and overall bestsound produced by the modestly pricedPS Audio xStream Statement, a triple-shielded design. With the ground-loopnoise fixed, and using the PS Audio inter-connects, the noise level was very low—nearly as low as I’ve heard in my system.

Perhaps the most enduring debate inthe audiophile world is the one betweenthose who want reproduced sound to be“accurate” and those who want it to be“musical,” with fans of solid-state equip-ment typically aligned with the formerposition and tubeophiles with the latter.And then, of course, there are people likeme, who want the sound to be accurateand musical. (I like to think that we’re inthe majority.) Of course, if the sound

produced by an audio system were, infact, a 100% accurate reproduction of theoriginal sound, the debate would have tobe over, but I don’t think we’re anywhereclose to that, even with the best systems.It’s this failure to achieve 100% accuracythat results in audio designers and audio-philes opting for various subtly differentapproaches to that presently unobtain-able ideal.

How did the sound of the ProLogueThree-Seven combo fit into this picture?Well, those aspects of the sound of theProLogue Three that I described as being“typically tubelike” became less so whenthe Three was paired with the Seven;now the sound had a more optimal com-bination of accuracy and musicality.Assuredly, the ProLogue Seven didn’t

sound like a beefy solid-state amp, but ithad less of the “typically tubelike” qualitythan, say, the Audiopax Model EightyEight. Combining the ProLogue Threewith the ProLogue Sevens maintainedthe open, transparent quality that I hadadmired when the ProLogue Three waspaired with the Audiopax, but the uppermidrange and treble acquired a bit morepresence. The result was that musicbecame more exciting to listen to, with agreater sense of drama. Those percussioninstruments on track 3 of Chesky’s JazzSampler were now more in the room, thehighs still staying well this side of shrill orexaggerated. Dynamics—a strong suit ofthe Avantgardes—were simply stupen-dous, with a “suddenness” and sense ofunstrained power that made recordings of




±120Hz appear around the fundamental tone at this power.Though they lie at –100dB, their appearance suggests thatthe power supply is starting to work hard. And at highishpowers of low frequencies into a matched load, the distor-tion is definitely starting to reach levels I would havethought audible (fig.17). The amplifier’s performance on thehigh-frequency intermodulation test, at levels below actualwaveform clipping (fig.18), was also a little disappointing,the 1% difference component resulting from an equal mixof 19kHz and 20kHz tones reaching –38dB (1.2%).

In many ways, the Prima Luna Prologue Three andSeven are nicely engineered, considering their relativelyaffordable prices. But the preamplifier’s decreasing lineari-ty at low frequencies definitely mean that it should not beused with power amplifiers whose input impedancedrops much below 50k ohms. And the power amplifier’shigh source impedance from all its output-transformertaps means that it will produce audible response changeswith pretty much every speaker with which it is used. Itdoes look as if the Prologue Seven’s owner would beadvised to use the output tap that is half the nominalimpedance of his speakers. This will give the optimal

tradeoff among nonlinearity, noise floor, and maximumpower; ie, the amplifier will work best with 8 ohm speak-ers using its 4 ohm tap.

—John Atkinson

Fig.16 Prima Luna Prologue Seven, 4 ohm tap, spectrum of 1kHz sinewave,DC–10kHz, at 20W into 8 ohms (linear frequency scale).

Fig.17 Prima Luna Prologue Seven, 8 ohm tap, spectrum of 50Hz sinewave,DC–1kHz, at 20W into 8 ohms (linear frequency scale).

Fig.18 Prima Luna Prologue Seven, 4 ohm tap, HF intermodulation spectrum,DC–24kHz, 19+20kHz at 20W peak into 8 ohms (linear frequencyscale).

large-scale orchestral works most excit-ing. Bass was firm and extended, andthere was a good sense of rhythmic driveon appropriate recordings.

Two amps in oneThe ProLogue Seven comes suppliedwith KT88 power tubes, but, as men-tioned earlier, it will also take EL34s, inwhich case it becomes, more or less, theequivalent of PrimaLuna’s ProLogue Sixmonoblock ($2295/pair). A set of eightEL34s can be had for as little as $16 eachfrom Upscale Audio; the ones KevinDeal sent me, bearing the PrimaLunalogo, sell for $20 each, for a total price of$160. Not bad for getting what is, ineffect, a different amplifier!

Once I felt I had a handle on thesound of the standard ProLogue Seven-Three combo, I removed the KT88s,substituted the EL34s, and let themburn in for a couple of days before doingany serious listening. Matching levels

with the listening sessions two days apartprobably isn’t too important, but I wasinterested in whether there was anychange in gain with the EL34s, so Ichecked the amplifier’s output voltage atmy usual listening level. Although I had-n’t touched the volume control, with theEL34s installed instead of the KT88s theoutput level was slightly higher (320mVinstead of 300mV), which I then com-pensated for by turning down the vol-ume slightly. Correspondingly, when Iswitched back to the KT88s, I had toturn up the volume control a bit to getthe same output level.

With EL34s instead of KT88s, theProLogue Sevens didn’t sound all thatdifferent. The noise level remainedlow—maybe even lower than with theKT88s—and the sound had the open,dynamic quality that characterized theSevens with the KT88s. Overall, I pre-ferred the Sevens with KT88s: thesound had a greater sense of depth, the

highs seemed more extended, and thedynamics seemed superior. But thedifferences were small, and it’s possi-ble that the EL34 tubes may not havehad enough time on them to be attheir best. And, of course, not allbrands of EL34s are alike, and theremay be some that sound distinctlysuperior to the stock KT88s. For folkswho are inclined to tune the sounds oftheir amplifiers by trying varioustubes, the ProLogue Seven’s AdaptiveAutoBias circuit lets you do this with-out the hassle of having to manuallyrebias them.

The sweet spotAs you ascend the price ladder of anyproduct category—cameras, cars,refrigerators, golf clubs, what haveyou—you reach what some call the“sweet spot.” This is where perfor-mance is at a high level but short ofthe very best available, and where anyadditional increments in perfor-mance will require spending dispro-portionately larger sums of money.For those in the market for a tubepreamplifier-amplifier combination,the PrimaLuna ProLogue Three andProLogue Seven hit this sweet spothead-on. With sound quality thatgives up little to much more expen-sive products, the ProLogue Threeand Seven are beautifully built, and,like the ProLogue One, reviewed byArt Dudley in the February 2006issue, they represent outstandingvalue.



ASSOCIATED EQUIPMENTDIGITAL SOURCES PS Audio Lamb-da II CD transport, Perpetual Tech-nologies/ModWright P-1A/P-3A digitalprocessors, Monolithic Sound P3power supply.PREAMPLIFIER Convergent AudioTechnology SL-1 UltimatePOWER AMPLIFIER AudiopaxModel Eighty Eight Mk.IImonoblocks.LOUDSPEAKERS AvantgardeAcoustic Uno 3.0, Silverline AudioPrelude, Fujitsu Eclipse TD-712z.CABLES Digital: Mystic ReferenceI2S, Illuminati Orchid AES/EBU. Inter-connect: Nordost Quattro Fils & Val-halla, AudioQuest Sky, PS AudioxStream Statement. Speaker: Nor-dost Valhalla. AC: PS Audio xStreamPower, Shunyata Research Taipan,TARA Labs Decade.ACCESSORIES PS Audio P-500 ACregenerator; Bright Star Little Rockatop CD transport, Shakti stone atopMonolithic Sound P3 power supply;Arcici Suspense Rack, Vistek Aurios1.2 MIB & Aurios Pro MIB compo-nent supports, PolyCrystal amplifierstands; Furutech RD-2 CD demagne-tizer. Digital source and preamplifierwere plugged into the regenerated-AC outlets of the P-500 (sinewave60Hz), power amplifiers into the pas-sive high-power Ultimate Outlets.

—Robert Deutsch

May 2007

PrimaLuna ProLogue Seven Monoblock Power Amplifier And ProLogue Three Preamplifier

Primo sound on a budget.

Review By Dick Olsher Click here to e-mail reviewer

If you are unfamiliar with the PrimaLuna line, then most likely you have been living under a rock for the past couple of years. PrimaLuna is hot; its ascent to an eminent position in the budget tube amplification arena having been paved with a chorus of critical acclaim. There have been other "East meets West" lines —designed in the West and built in China — but none as compelling as PrimaLuna. A major factor in its success and product reliability is no doubt attributable to direct oversight of the manufacturing process.

The ProLogue Seven is billed as a classic Ultralinear circuit based on a quartet of KT88 beam power tubes (70 wpc) used in push-pull topology. Chinese new production copies of the venerated Genalex KT88 are standard. As with other PrimaLuna amplifiers, a soft-start circuit extends tube life and an Adaptive AutoBias™ circuit monitors and automatically adjusts tube bias current for improved performance and reduced distortion. Hence, there are no messy adjustment pots and burnt fingers to contend with. And best of all, forget about matching output tubes. PrimaLuna even gives you a green light to experiment with a variety of power tubes. The following types may be substituted for the stock KT88s: 6550, EL-34, 6CA7, 6L6GC, KT66, or 7581.

Some feedback is used both inter-stage and globally to reduce both harmonic distortion and output impedance. The power supply incorporates a toroidal transformer and rectifiers are fast-recovery solid-state diode types for reduced noise. The output transformers are said to be custom designed for wide bandwidth. Impedance taps are provided for 2-, 4-, and 8-ohm loads. Wiring is high-quality point-to-point, and in general, parts quality is excellent featuring Nichicon and Solen caps. The chassis is made of heavy gauge steel and finished using a five-step automotive finish. A removable tube cage is included at no extra charge. In terms of parts and build quality, what more could you ask for at a $2,695/pr price point?

Sonic Impressions

If you have never heard a good KT88 based amplifier, then you are in for a treat. The midrange is definitely worth writing home about. Imagine diving head first into a tropical pond. The sensation of being enveloped in a warm, liquid, and inviting sonic cocoon was quite perceptible. Harmonic textures were consistently smooth but not to the point of fuzzing over ambient information and low-level detail. There was a time in the 1950s and 60s when you could confidently expect a tube amplifier to sound warm and inviting. The Seven, however, is not obsessive-compulsive about tubey euphonics. It strikes an admirable balance between detail and liquidity. In particular, the Seven re-kindled fond memories of the Harmon Kardon Citation II, though lacking the latter’s bass authority. It is fair to say that sonically this amplifier obeys the Goldie Locks principle, never excessive in its pursuit of tube sound.

The Seven, throughout an extensive audition period, possessed a high quotient of fatigue-free listening; mellow, and never bright and obtrusive though the presence region, but a tad too laid back (i.e., ever so slightly bleached harmonic colors) for my taste through the upper midrange. I should hasten to add that results will likely differ in a manner dependent on the power tube complement. To forestall pesky reader questions about power tube substitutions, and partly to satisfy my own curiosity, I broached the subject with the US distributor, Upscale Audio’s Kevin Deal. He was kind enough to provide me with a set of Russian (SED brand) 6L6GC tubes to experiment with. The Russian 6L6GC turned out to be crisper sounding relative to the Chinese KT88. By that I mean that third-order distortion products were more pronounced, which only served to highlight the KT88’s more vintage character. I am quite partial toward the Chinese Genalex KT88 copy, at least in this application. In terms of reliability, I only experienced one mishap. One of the KT88s arced and had to be replaced. But other than that, the Seven performed flawlessly even when driven hard into a difficult speaker load such as the MartinLogan Vista.

Image outlines were tightly focused with good dimensionality. But the soundstage was not fully illuminated so that its inner recesses were not clearly resolved, which when combined with a slight loss of clarity somewhat blunted the presentation’s immediacy. The microdynamic ebb and flow of the music’s harmonic tapestry were nicely reproduced. And there was no problem revving up into higher gear, though there was some compression evident while scaling the range from loud to very loud relative to much more expensive amplifiers.

The usual tube amp suspects were noted at the frequency extremes. The treble was slightly closed in, lacking a bit of finesse, and the bass range lacked the ultimate in control and visceral impact. Note: it really pays to experiment with various impedance taps to optimize the overall sound for a particular speaker load. Overall, the Seven appeared to perform no worse at the frequency extremes than other comparably priced tube amplifiers.

Enter the ProLogue Three

The Three would have easily gotten thumbs up as a good value even with a price tag of $3K. But at $1,395 it represents an amazing value (an optional moving magnet module is available at $179). Note its weight. At 23.5 pounds this is one beefy line preamplifier. The weight is a result of an ambitious dual mono layout

featuring independent power supplies. That’s right, there are two toroidal power transformers, choke filters, and two 5AR4 rectifiers, one per channel. Throw in premium caps, point-to-point wiring, an Alps Blue Velvet pot, DC tube heaters, and wideband no-feedback circuitry and you have a serious sonic contender at any price point.

There is no balance control. Given the dual mono layout, I would have preferred to see dual pots, one per channel for independent tweaking of the volume level. On purist grounds, no cathode followers are used at the output stage, which for this circuit translates into a high output impedance of about 3.5 kOhm. I would recommend a matching power amplifier input impedance at least a factor of ten higher to minimize treble rolloff. Since the Seven’s input impedance is 100 kOhm, this criterion is easily satisfied.

This is one clean, liquid, and sweet sounding line preamplifier. Tube rectification bestows a vintage character to the sound that is hard to match in a world run amuck with solid-state rectifiers. If you think your system needs an injection of a high-carb midrange additive, then the Three would be the ideal vehicle for it.

There was undeniable synergy when the Three was introduced into the system, which is the main reason for combining these two components into one review. The focus now was clearly on the midrange, which took on a smoother and sweeter luster. Harmonic textures bloomed to a degree that is rare for a push-pull tube amplifier. And it was not just about the sugar. Low-level modulations in pitch, volume, and rhythm that convey a singer’s emotions were more clearly captured. As a consequence, reproduction of female voice now bordered on the spectacular, being more emotionally charged. Soundstage spatial outlines benefited as well in terms of enhanced depth and width perspectives. Transients were a tad softer sounding, which is not necessarily a bad thing in the context of a bright digital front end or a loudspeaker with a relentless treble range. Again, it is important to emphasize that despite its classic tube virtues, this combo did not fuzz over low-level detail with an overly liquid or gooey sound — ala the Dynaco Stereo 70. Aficionados of classic tube sound take note: you can now have your cake and eat it too!

Conclusion

Be sure to experiment with the various impedance taps, and I would not be in any rush to substitute alternatives for the stock Chinese "Genalex" KT88. Undeniably, the Three brings out the best in the Seven and you should give serious consideration to auditioning both components as a system. In my book, and in the context of budget tube amplification, the ProLogue Seven and Three add up to a perfect 10.

Addendum

Just the other day I happened to come across a small cache of GE four-star 5751 dual triodes, which have been collecting dust on a storage shelf. So what to do with them? A light bulb went off, as I recalled those Chinese 12AX7s in the Prologue Seven's front end. Yes, the 5751 is a lower gain version of the 12AX7 which would reduce the amplifier's sensitivity and drive voltage, but I thought it was worth a shot. A couple of minutes later, I settled down for a listen. In a nutshell, the results were very positive. Harmonic textures were smoother and the overall presentation more direct with enhanced focus and low-level detail. The moral of the story: rolling-in your favorite substitutes for the stock 12AX7s would be a good thing to try.

Imaging

Fit and Finish

Self Noise

Value for the Money

Specifications

ProLogue Seven

Type: Vacuum tube monoblock amplifier Power Output: 70 wpc Tube Compliment (per amp): two 12AX7, two 12AU7 and four KT88 Frequency Response: 20Hz to 85kHz (+/- 0.5dB) THD: Less than 1% at full power S/N Ratio: 101dB Input Sensitivity: 911 mV Input Impedance: 100 kOhms Power Consumption (per amp): 225 watts Dimensions (per amp): 11 x 7.5 x 15.5 (WxHxD in inches) Weight (per amp): 37.5 lbs. Inputs: 1 pair RCA Outputs: 2, 4, & 8 Ohm speaker tapsPrice: $2,695/pr.

ProLogue Three

Type: Vacuum tube preamplifier Inputs: 4 pair RCA Outputs: 2 pairs of pre-amp outputs + tape monitor out Frequency Response: 4Hz to 85kHz (+/- 3dB) Gain: 11.5dBTHD: Less than 1% at full power S/N Ratio: 109dB unweighted Input Sensitivity: 200mV Input Impedance: 100k OhmsOutput Impedance: 3.5k OhmsPower Consumption: 48 watts Dimensions: 11 x 7.5 x 15.5 (WxHxD in inches) Weight: 23.5 lbs. Price: $1,395

Company Information

Durob Audio BV P.O. Box 109 5250 AC Vlijmen The Netherlands

E-mail: [email protected]: www.primaluna.nl

US Distributor Upscale Audio 2504 Spring Terrace Upland, CA. 91784

Voice: (909) 931-9686 Fax: (909) 985-6968

Tonality

Sub-bass (10Hz - 60Hz)

Mid-bass (80Hz - 200Hz)

Midrange (200Hz - 3,000Hz)

High-frequencies (3,000Hz on up)

Attack

Decay

Inner Resolution

Soundscape width front

Soundscape width rear

Soundscape depth behind speakers

Soundscape extension into the room

ProLogue Six Reviews

Equipment Reports

WHERE DOES ONE FIND HIGHLY MUSICAL AND RELIABLE, FULL-RANGE TUBE MONOBLOCK AMPLIFIERS FOR AROUND $2K PER PAIR THAT ARE CAPABLE OF DRIVING MOST ANY LOUDSPEAKER, WHILE ALSO AVOIDING THE SYRUPY THICKNESS, SOGGY LOW END, AND ROLLED-OFF HIGHS OF MANY CLASSIC TUBE DESIGNS? I’ve been searching for amps with these attributes ever since I loaned a “former” audio buddy my custom MFA-140s, with six EL34s per chassis, and he sold them! A few new entries in the amplifier sweepstakes from China appeared to fit the bill, but my initial optimism over them waned after examining the build-quality, or should I say variability, of several. Perhaps I’m overly sensitive after recently speaking with the head of one audio company whose factory in China began using counterfeit parts, unbeknownst to him, until there were several failures in the field. Yet, I’m also aware of some companies who “ride herd” on their Chinese factories and are able to produce products with exceptional build-quality for a modest cost. PrimaLuna is one prime example. The combination of its new monoblocks driving a pair of Sonus Faber Amati Anniversario speakers sounded glorious at CES, so I thought they just might be the answer for me—not only to drive my Quads, but most any other speaker.

The PrimaLuna Prologue Sixes come standard with four EL34s per side. I chose to review the Sixes instead of the KT88-based Sevens, because I prefer the more liquid midrange of the EL34 tube and am willing to trade-off a bit of bass punch and extension at the frequency extremes. You may not be. While the Sevens are slightly more expensive ($2400), they do offer upgraded Solen caps and fast-recovery diodes. Both versions use point-to-point wiring, which I prefer, not only for its potential sonic advantages, but also for its ease of servicing and modifying. It’s a big reason why so many of the classic McIntosh and Marantz tube amplifiers are still working rather than being used as boat anchors. However, just because an amplifier offers point-to-point wiring doesn’t mean it’s always better, particularly if the solder joints are sloppy. There’s no need to worry here, as the workmanship on the Prologue Sixes is first-rate and puts the build-quality of several far more costly amplifiers to shame. These amplifiers seem to be

Where does one find a musical, reliable, and full-range tube monoblock for around $2k?Jim Hannon

PrimaLuna ProLogue Six Monoblock Amplifier

“The ProLogue Sixes are as

at home with Audioslave as they are with

Miles and Mahler.”

October 2006 The Absolute Sound 101

built for those who plan on owning them for decades instead of a few years.

If you had assumed that all tube amplifiers were finicky, think again. My Sixes have operated flawlessly with nary a hiccup. The PrimaLuna team has seemingly designed out all the potential problems one might encounter with a tube amplifier. It starts with the package design (each amp is triple-boxed) and extends to several product features that make these tube amps virtually trouble-free. For example, the output tubes are gently driven—the Prologue Six’s soft-start feature extends tube life and reduces the chance of both tube and internal part failures, while the amplifier output stage is protected by a fuse, and the “Adaptive Autobias” circuit keeps tubes operating at their peak ranges and reduces distortion significantly. Better still, there’s no need to monkey around with bias meters and pots or use matched sets of tubes. If you know how to change a light bulb, you’ve got all the skill you need.

OK, so what more could these PrimaLunas offer beyond the Prologue Fives that Sallie Reynolds recommended for a previous Editors’ Choice Award? The most obvious advantages are that the Sixes have more power, a separate chassis for each channel, new wideband transformers designed to handle difficult speaker loads (a 2-ohm tap is included), and a unique front-end topology which reportedly gives you all the sonic advantages of zero feedback but with drive capability, extension at the frequency extremes, and low distortion. Although there are some mighty good “dual-mono” single-chassis stereo amps in this price range, I prefer monoblocks, because they physically isolate the channels, and one can place the amp right behind the speaker, connecting to it with a very short length of cable.

Unlike many larger amplifiers that seem to lose some of the magic enjoyed by their smaller counterparts, the good news is that the Prologue Sixes not only retain the sonic virtues of the PrimaLuna stereo amplifiers, but extend them. Their performance with my original Quads was superlative, with a transient quickness rivaling a very good solid-state amplifier but with harmonic richness, natural timbre, and a wide and focused soundstage. You won’t find any homogenization of sound with these tube amps as they revealed even minor system changes, so you’re out of luck if you expect to use them as tone controls to tame bright speakers. Even more surprising, the Sixes drew more bass and dynamics out of my original Quads, using KT66 output tubes, than I thought possible and forced me to turn down the gain because the music was too loud—imagine that!

The Sixes are as equally at home reproducing the sounds of Audioslave as they are with Miles or Mahler. I typically wouldn’t recommend most 70-watt tube amps as ideal choices for power rock and electronica, but these amps have satisfying deep bass and really swing dynamically and rhythmically. On classical music, the transient speed of mallets hitting tympani can be startling, and violins have both bite and body, without sounding harsh. These amps reveal a lot of the natural subtlety in the music, and acoustic instruments and voices can sound life-like on good recordings. I sat transfixed listening to the late Hawaiian singer Israel Kamakawiwo’ole’s cover of “Over the Rainbow” from Alone in IZ World [Mountain Apple Company]. There was a musical rightness from the lightning attack of the fingers strumming the ukulele, to the natural timbre of the instrument, to the air behind his floating, lilting voice.

While they may lack the ultimate sweetness, palpability, and absence of grain of some far more costly triode designs, or the absolute quietness, inner detail, and power reserves of some expensive transistor amplifiers, the Prologue Sixes gave a surprisingly good accounting of themselves. These amplifiers are obviously designed for those who want to enjoy the musicality of tubes without having to be tweaks; yet the PrimaLunas make an ideal platform for those audiophiles who love to

experiment with “tube-rolling” and customize the sound (within limits) to their own preferences. They are optimized for EL-34, 6L6GC, KT66, and 7581 output tubes, but are also said to work with KT88s, 6550s, and KT90s. Yes, you can get different, but not always better, sound with different types of output tubes. If you want a bit more clarity and dimensionality, but a more recessed upper midrange, you might try the 6L6GC. If you want a bit more bass punch and transient speed, but less liquid mids, try some KT66s. I can’t really say I preferred one type overall, as it depended on which speakers I was using. But remember, you can leave well enough alone and the sound will be really good.

The PrimaLuna Prologue Sixes represent a significant breakthrough in high performance audio. Not only are they the most “hassle-free” and easy-to-operate tube amplifiers I’ve ever used, but they sound really good. The Sixes rival many (but not all) of the best attributes of transistor amps, but they also enjoy the compelling sonic virtues of tubes, while largely minimizing their drawbacks. To get this combination of natural musicality, power, reliability, flexibility, and build-quality, one would expect to spend far more. These surprisingly good tube monoblocks should keep many demanding audiophiles satisfied, but also encourage lots of music enthusiasts to take the plunge into the tube-side of the pool.

PrimaLuna ProLogue Six Monoblock Amplifier

Specs & PricingDISTRIBUTOR INFORMATIONUPSCALE AUDIO2504 Spring TerraceUpland, California 91784(909) 931-9686 upscaleaudio.com

SPECIFICATIONSPower output: 70 watts per channelInputs: One RCA per chassisOutputs: 2-, 4-, and 8-ohm speaker tapsTube complement: Two 12AX7s, two 12AU7s, four EL-34s (per amp)

Dimensions: 11" x 7.5" x 15.5"Weight: 37.5 lbs. (each)Price: $2295/pair for EL34-based version

ASSOCIATED EQUIPMENTMFA Venusian preamp (modified); VPI Aries/Graham/Koetsu Black, and Clearaudio Ambient/Satisfy/Concerto analog turntable set ups; Musical Fidelity Tri-Vista 21 DAC; Eben X-3, Hyperion HPS-938, and Quad ESL-57 (PK modified) loudspeakers; Nordost Valhalla and Virtual Dynamics “David” interconnects, speaker cables, and power cords

“If you know how to change a light bulb,

you’ve got all the skill you need”

102 October 2006 The Absolute Sound

There are many options when it comes to powering two-channel systems when using separates. However, the preponder-ance of options involves solid-state amplifi-ers, and if you choose a tube amp and are at all concerned about how much green you need to lay out, you aren’t going to be able to procure that much wattage. Thanks to the Dutch company PrimaLu-na, their Chinese-built ProLogue and Dia-Logue series amplifiers make acquiring a relatively high-powered tube amp a reality. Not only do these amps have more than enough wattage to drive most speakers,

but also they are of extremely high build quality, are easy to maintain, and have ex-ceptional sound quality (Photo 1).

Most of PrimaLuna’s integrated and power amps have been more than posi-tively reviewed in the mainstream audio magazines. I wondered whether a pair of their 70W ProLogue Six monoblocks could drive a pair of power hungry, low impedance hybrid electrostats. Of course, I was willing to start out using them in a smaller system using stand-mounted two-way speakers. It would be a better repre-sentation of how a good number of audio-philes will use these amps.

FIRST IMPRESSIONS AND BASICSEach amp arrived at my doorstep triple-boxed and packaged with the tubes in-stalled. The large main power tubes (four EL-34s in each) were wrapped in soft Styrofoam, and white cloth gloves were supplied to check the seating of the tubes and handle the glossy finished, nearly 38 lb units. My samples had silver faceplates,

which are also available in black. You can easily remove the tube cage, which is held in place with pegs that fit the cage snugly into place corresponding to the exempla-ry external fit and finish of the amps. The internal fit and finish was also exemplary, with soldering work and layout designed as though the owner of these amps was going to use them upside down with the covers removed and their innards dis-played for all to see (Photo 2).

On the rear of each amp are a gold-plated RCA single-ended input, four heavy-duty speaker terminals, one common, and terminals for 2, 4, and 8Ω loads. I tried

both the 2 and 4Ω outputs when power-ing the electrostatics, and really didn’t hear any difference between the two, but ended up using the 2Ω tap recommended in the manual. I used the 4Ω taps for the small speakers. There is an IEC AC power socket for the detachable power cord and a place for the 5A fuse. The large power switch is on the left side of the amp near the front.

In addition to the quartet of EL-34 out-put tubes, each amp has a pair of trusty small 12AX7s and 12AU7s in its input section (PrimaLuna buys their tubes from a Chinese supplier, but rejects about 40% of these because they don’t meet their standards). PrimaLuna claims that tube life is extended because of their soft-start circuit, which powers up the tubes slowly when the power switch is turned on. The manual recommends turning the amp off when not in use, with no need to run up your electric bill to keep the amps warm when you are not listening to them.

PrimaLuna also claims that these amps are of the “plug and play” variety—an “adap-tive autobias” circuit monitors and adjusts the tube’s bias automatically. This makes it possible to use unmatched sets of tubes, possibly saving you some money when eventually you need to replace the tubes. This circuit also makes it possible to exper-iment with different types of tubes. On the

PrimaLuna ProLogue Six Tube Monoblock Power Amplifiers By Tom Lyle

“Soldering work and layout [were] designed as though the owner of these amps was going to use them upside down with the covers removed and their innards displayed for all to see.”

Upscale Audio

2504 Spring Terrace

Upland, CA 91784

(909) 931-9686

Fax: (909) 985-6968

www.primaluna-usa.com

Price: $2,599 a pair

PHOTO 1: PrimaLuna’s ProLogue tube amp.

distributor’s website, they claim you can use 6550, KT88, KT90, 6L6GC, KT66, 7581, or even 6V6GT tubes instead of the EL-34s. [Manufacturer’s note: Though the PrimaLuna is fine with 6V6GT tubes, we are no longer recommending those because there are some low quality ones out there, and instead, we recommend EL-37—Kevin Deal, PrimaLuna USA].

The custom output transformers were designed by an American engineer, then the final design was done by Marcel Cro-ese, who supposedly is a very renowned transformer designer. A good transformer design should lower the noise floor and extend the frequency response.

PrimaLuna says that the ProLogue Sixes have a “dual-feedback topology” which is a cross-coupled current feed-back for superior impulse behavior and gain stability. A slight amount of negative feedback is used to achieve exact gain setting, low distortion, and low output impedance. PrimaLuna claims that this effectively cancels the negative side ef-fects associated with both feedback cir-cuits. The end result utilizes all the bene-fits of feedback without the drawbacks.

The ProLogue Six is made with many quality parts. For example, no plastic tube sockets here, only ceramic sockets are mounted on the chassis. Internally, PrimaLuna uses Nichicon and Realcap capacitors, a toroidal transformer, and the amp is handmade with non-cost-ef-fective point-to-point wiring throughout.

LISTENINg—SySTEM ONEThe smaller of the two systems consists

of a digital front end (Arcam) and an ana-log front end of an old FM tuner (AR), either a solid-state (Jeff Rowland De-signs) or tube (Balance Audio Technolo-gies) preamp. The speakers I used were Dynaudio Focus 110.

If you are interested, the preamp-to-amp interconnects are Cardas, the CD to preamp is Monster Cable, and the tuner is connected with out-of-the-box-type cable. The speaker cable is sometimes Kimber, sometimes Monster. I use the stock pow-er cords and no power conditioner. The PSB speaker stands are filled with marble gravel, and all the other equipment sits on the hardwood floor atop and separat-ed by antique Audio-Technica pucks.

While the amps were in either system, I heard no complaints—there were no buzzes, hiccups, static, or any extrane-ous noises at any time. I could hear no background noise other than a slight hiss when I turned up the volume on the pre-amp and put my ears up to the speakers. Other components could have contrib-uted to this background noise.

After they were just about fully broken in, which took about two weeks of on and off use, the PrimaLuna ProLogue Six-es sounded magnificent in this system—even when listening to the FM tuner, which was usually set to the local jazz station WBGO in Newark, N.J. (terrestrial out-and-out jazz stations are very scarce these days). On one occasion there was a solo tenor sax playing (I think it was a recent Sonny Rollins release). Its sound entered the room with such a pure tone it was disquieting.

When using the CD player, of course, things became better. One high point was Wilco’s Yan-kee Hotel Foxtrot. When play-ing this CD the system sounded alive: the treble had a natural timbre, and both the mids and highs had a rightness that made this disc sound as good as it ever has—with a tube sweetness that was addictive. This tube sweet-ness was not a euphonic color-ation, but it included as one of its features a less forward sound

that diminished listening fatigue to a point that made for some very long lis-tening sessions.

When I played orchestral discs such as Sibelius’ symphonies with Colin Davis conducting the LSO on RCA, the string sound was luscious in large part because midrange was so accurately portrayed. There was no loss in resolution anywhere in any frequency, and there was an abun-dance of what I like to call “dynamic dis-tance” between sounds—that is, the sepa-ration of two or more instruments playing simultaneously but at different volumes.

I could kick out the jams, too, playing “Wasted Years ‘99” from Iron Maiden’s Best of the B-Sides, which was included in the Iron Maiden box set (packaged in a metal casket, by the way). There was plenty of power displayed in the crunch-ing guitars and thunderous rhythm sec-tion. The non-pumped-up midbass shook the air, which says a lot for the superb speakers, at least from 40Hz on up.

When I came back to earth, I played the Kronos Quartet’s album Pieces of Africa, and reveled in the sound of the individual strings and percussion instruments clearly portrayed in the space of the proportion-ally scaled soundstage. I’m not going to say that the instruments sounded indis-tinguishable from the real thing—that’s ridiculous—but it sure was impressive how lifelike this CD sounded in this relatively modest system. The PrimaLunas and the Dynaudios were a perfect match.

LISTENINg—SySTEM TwOThis system is in my main listening room and consists of analog (Basis/Tri-planar/Lyra turntable setup and an NAD FM tuner) and digital (Arcam and Oppo) front ends, a tube preamp (Balance Audio Tech-nologies), and Sound Lab Dynastat hybrid electrostatic speakers, sometimes aug-mented by a Velodyne sub. If you care, the interconnects are either MIT or Virtual Dy-namics, the speaker cable MIT, power ca-bles Virtual Dynamics and MIT, and all the equipment is plugged into either PS Audio Power Plants or a Chang Lightspeed con-ditioner. Then these are plugged into Vir-tual Dynamics wall receptacles with two

PHOTO 2: Inside the ProLogue amp.

dedicated 15A lines. Most of the equip-ment rests on an Arcici Suspense equip-ment rack, and the room is treated with Echo Busters acoustical panels.

When I first had the amps in this sys-tem, I was careful. I didn’t want to judge the amps too harshly with complex mate-rial, so along with some other small com-bo recordings, I played an LP of Julliard String Quartet’s version of Bartok’s String Quartet No. 6. The amps sounded good, but they had a more burnished, laid-back sound than I was used to. But they were reasonably neutral sounding, a little rolled off in the highs (which as a benefit re-duced the background noise on the old record), and a little less defined in the midrange and mid-bass than absolute, but the overall sound was very good.

As far as the decrease in treble energy, nobody is going to describe the Sound Lab speakers I use as bright sounding; some might even say they are a little rolled off. I disagree. I find them to be extremely

transparent in the treble region, but I’ve used them as my reference for years, so I’m probably used to them.

Nevertheless, when I played the SACD layer of Stokowski’s Rhapsodies album, a Living Stereo re-issued by BMG, the sound of the solo instruments on an excerpt from Wagner’s Tristan and Isolde sounded rath-er lifel ke—especially the English horn—and I could clearly sense the ambience of NYC’s Manhattan Center. The amps were able to sort out more complex fare—even when I threw on some convoluted rock (or whatev-er you want to call it) such as Frank Zappa’s Weasels Ripped My Flesh. The amps kept their composure (even when the musicians did not) while playing this thorny music.

But, even with all their positive traits, I wasn’t totally blown away. They were just too rolled off in the highs for my taste, and the midrange was a tad too recessed. I could only chalk that up to a combina-tion of the speaker’s relatively soft highs (although, again, I’m prepared to debate

that fact), perhaps their demand for high power, and their challenging impedance characteristics.

TUBE SwITCHWhen speaking to the US distributor of the PrimaLuna, Upscale Audio’s Kevin Deal, I think he sensed my lack of enthusi-asm for the combination of the ProLogue Sixes and the Sound Labs. He said he’d send me a set of PrimaLuna KT88 power tubes to try out instead of the stock EL-34s. They arrived about five days later, and I installed them forthwith.

The improvement in the sound of the amps was extraordinary. The midrange reached a more natural level and was much more defined, and the highs were restored to a point where their extension nearly rivaled a solid-state amp, yet in-struments within both frequencies were rendered with what I can only describe as tube sweetness. It was a very lifelike sound, which included excellent separa-

tion of individual instruments and groups of instruments. There was ample power in the bass, and the overall sound of the amps was extremely inviting.

I played a new favorite of mine—Nine Inch Nails’ Year Zero CD. The album came across as aggressive and relentless, which was as it should be. Turned up nice and loud, the bass shook the walls. Synths and the hammering percussion sounds were upfront and distinct, yet incorporated into the dense mix to form the intense wall of sound. Wonderful stuff.

The sometimes raucous CD of Prokofiev’s complete soundtrack of Alexander Nevsky with Uri Temirkanov conducting the St. Pe-tersburg PO was superb. Like the NIN, this is a dense recording (Romeo and Juliet, it ain’t), yet the ProLogue Sixes had no prob-lem sorting out the orchestra, chorus, and soloists. But in contrast to the NIN the par-ticipants and the space were real, and it was like I had a tenth row seat during the record-ing session. The highs were sweet and cred-ible and the mids were well sorted out in the very intricate, large soundstage.

I loaded the Zappa disc again, and was reminded that the recording was a bit bright. But despite this, it was almost as though I was listening to a live mike feed in the studio rather than a CD. The drums, in particular, were outstanding, in part be-cause the transient response was surpris-ingly good; there was a snap to the sound that I wasn’t expecting from a tube amp.

I also spun the best pressing I have of Jimi Hendrix’s Axis Bold as Love LP, a mono press-ing reissued by Classic Records (vinyl, tubes, mono—please help me). This version, of course, disposes of the psychedelic hard left-right pan-ning and presents the album in a much more listenable arrangement. I was able to follow and dissect all the overdubbed guitar and ef-fects. But especially good was “Little Wing,” which wasn’t laden with overdubs and let me hear all that engineer Eddie Kramer dialed into the mix, particularly the goose-bump-raising flanged guitar. I admit that the recording qual-ity isn’t the greatest, and the PrimaLunas did not fail to disclose that fact.

Because I was stuck in the 1960s for much of my listening of late, I played “India”—the first cut on Coltrane’s Impressions album on a Japanese Impulse pressing, recorded

at the Village Vanguard in 1961. The track takes up most of side one (John Coltrane and Eric Dolphy together—it doesn’t get much better than this).

Even though the highs were a smidge softer than I’m used to, they were very re-vealing, and there was lots of air around the horns. The low end and mid-bass were also fine; the dual basses of Reggie Workman and Jimmy Garrison weren’t too meshed together, so it was possible to identify each instrument. The recording quality is very good; I just wish McCoy Tyner’s piano wasn’t mixed so low. The vinyl is silent, with the only background noise being the tape hiss which the PrimaLunas made clearly evident. (Depending on how you look at it this was or was not a good thing.)

As I continued to live with the amps, I realized there wasn’t any type of music that could trip them up, and the more I used them, the more I appreciated their sound. CD after CD, record after record, the midrange had an impressive ability to separate out all the instruments in any mix, and both the mids and the highs exhibited the tube magic that I’ve come to expect from a great valve amp. This “tube magic” wasn’t the old-school-type of tube sound—rolled off in the bass and highs, and their only strength the midrange—it was more that instruments had that dynamic dis-tance I mentioned when using them in the smaller system, combined with less in-your-face forwardness than the majority of affordable solid-state amps.

I was skeptical; I’ve had other tube amps paired with these speakers before, all with less power than the PrimaLunas and with mixed results. But still, even with 70W per channel, I didn’t think the Sixes would have enough power to drive a pair of these rather large electrostatic/dynam-ic speakers. I was wrong.

I needed to turn up the volume on the preamp higher than I did with a 250W per channel solid-state power amp, but this did not in any way increase the back-ground noise. I had no trouble reaching the volume limits of the speakers, which was quite loud—loud enough for me to back off a little to prevent possible hear-ing damage. What I can’t explain is why I

didn’t need to turn up the volume so loud. I could listen to music at lower dBs with the Sixes than I was accustomed to, and still consider it to be an acceptable level.

CONCLUSIONI think many audiophiles will like the fact that simply swapping tubes can have such a dramatic effect on the sound; I could only imagine what a field day a tube roller would have swapping different brands and vintag-es. Others will not want to mess with such stuff, and I guess they’ll just have to stick with the stock tubes or use a solid-state amp. I can appreciate both worlds. But I must admit that after replacing the KT88s with the stock EL-34 tubes and bringing the amps downstairs again to use with smaller speakers, it was a better match. They spent a lot of time in that system, and I could live with these amps forever.

Ultimately, I preferred the control and power of the solid-state muscle amp in the big system; I think that’s a matter of taste more than which one was “better.” There is a chance that you might prefer the PrimaLunas with your large electro-static speakers, even with the warmer-sounding stock EL-34s installed. I pre-ferred the tubed PrimaLunas by a wide margin in the smaller system.

But wait—if you have the money, the next step up is the PrimaLuna ProLogue Seven mono amps that come standard with KT88s and upgraded internal parts, also at 70W per channel, for $3149. Loading up a pair of ProLogue Sixes with PrimaLuna KT88 tubes will cost you about $280, so the price comes within shouting distance of the ProLogue Sev-ens. I’m not totally sure, but it seems that the Sevens might be the more sensible choice when used with large speakers.

Still, the majority of customers will use them with more efficient speakers, and to them I give the PrimaLuna ProLogue Sixes my highest recommendation. From my eval-uations, using them with large speakers is not out of the question, and quite sensible if you have a hankering for tubes and don’t want to take out a second mortgage to do so. I’m not going to pretend that $2600 is pocket change, but the PrimaLuna ProLogue

Six monoblocks are worth every penny.

Manufacturer’s response:All of us associated with PrimaLuna wish to gra-ciously thank Tom Lyle and audioXpress for the thorough and thoughtful review of the ProLogue Six Monoblock Power Amplifiers. When Tom writes that the amps “sounded magnificent,” that “. . . there wasn’t any type of music that could trip them up,” and that his experience was “. . . like I had a tenth row seat during the recording ses-sion,” we all can only smile because in a nutshell, he articulates exactly what we’re all about.

We’re especially pleased that Tom spent the time and effort to evaluate the amps in two sys-tems. It comes as no surprise to us that the Pro-Logue Sixes performed magnificently in both.

We’d like to highlight one of those evalua-tions—his experience with the Dynastat electro-static speakers—because it illustrates a wonder-ful point. Tom states that initially, he was not particularly thrilled with the EL34-based mono-blocks pushing the Dynastats—the highs were “a little too rolled off” and the mid “a tad too recessed.” He speculated that perhaps it was the speaker’s demand for high power or maybe their challenging impedance characteristics. We sug-gested switching tubes and shipped him a set of stock PrimaLuna KT88s. And night turned to day. Tom writes that the improvement in sound “was extraordinary” and then spent the next 10 para-graphs raving about the amps’ characteristics.

The point to be taken from this is that you nev-er know what kind of speakers you may wind up with. All PrimaLuna products can be tweaked—nudged, if you will, in a particular direction and that gentle nudge can be exactly what turns a mundane experience into an extraordinary one.

We sincerely appreciate Tom’s willingness to recommend these monoblocks for use with pow-er-hungry speakers like the Dynastats; I have yet to find a speaker the ProLogue Sixes can’t drive. I’ve paired it beautifully with my Sonus faber Guarneris and have heard raves from people who use it to drive difficult loads such as Martin Logan Vantag-es (impedance—4Ω, 1 at 20kHz).

Thanks again for the glowing evaluation. When a reviewer is moved from non-plussed to ecstatic by simply switching tubes, we know we’ve cre-ated something special.

Kevin DealPrimaLuna, USA

rr

ProLogue Seven Reviews

TONEA NO.3 2 0 0 6

The e-journal of analog and digital sound.

no.3 2 0 0 6

DAY TRIPPIN’taking in music from the 80s

MUSIcREEl-To-REEl

steve hoffman onthe dehavillandaries 845-g

olD School:Life With the Quad 57'sfrom chris Beeching

REGA AccessoriesAnd clean Vinyl

revieWs, music and so much more.

TONEA NO.3 2 0 0 6

r e v i e w

Encore Presentation: The PrimaLuna Prologue 7

Monoblocks — Jeff Dorgay

TONEA NO.3 2 0 0 6

r e v i e w

I can see it now; “Ralph lauren introduces Electron – For the Nerd in You!” Well, maybe I

better keep my day job for now.

(continued)

The PrimaLunaPrologue 7 Monoblocks

here at TONE-Audio, (along

with almost everyone else in the

audio world) we like PrimaLuna

products for a number of rea-

sons; they offer great value, are

stylishly understated, extremely

well built and sound great.

There has only been one collec-

tive request from reviewers and

owners alike – more power!!

As we just recently reviewed the ProLogue 5 power amplifier in issue one, this will be a fairly short review, because that’s what the folks at PrimaLuna did, serve up more power.

The basic sound and character is intact here, albeit a bit more refined. If you enjoyed the other products from PrimaLuna, but shied away because 35 watts per channel just wasn’t enough, your answer is here. I first saw them in the Upscale Audio room in January at the CES show and was amazed to see that they had these amps (and the PL preamp) hooked up to a pair of 28 thousand dollar Sonus Faber speakers.

Ambitious for sure, and while the little PrimaLuna amplifiers did not possess the control and resolution as some five figure electronics I heard elsewhere, it had a very musical sound that was fundamentally correct and a lot more fun than some of the other systems I heard that cost more.

Family Resemblance

As you know from reading my last review of the PL preamp and power amp, I really

enjoyed them and thought the PL preamp, with it’s dual mono power supply and tube rectification was the real jewel of the pair, but the amplifier needed a bit more juice. The Prologue 7 answers that issue, with 70 watts per channel, using four KT88s per channel instead of the two in the Prologue 5, which uses one chassis. Spreading this out to two

chassis with separate power supplies really gives you the Prima Luna sound with more authority. Now you have to buy another fancy power cord, but hey, that’s what being an

audiophile is all about, buying stuff.

Success has not gone to their heads at PL. Everything is still triple boxed and the white gloves are of higher quality than the ones that came with our ProLogue 1 two years ago. Call me wacky, but I really like the smell of new PL gear in the box. It just has a unique, very electronic smell to it. You can smell the resistors and the transformers. I can see it now; “Ralph Lauren introduces Electron for the nerd in you!” Well, maybe I better keep my day job for now.

TONEA NO.3 2 0 0 6

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The PL sevens use the same chassis as all past PL products, which no doubt keeps production easier and costs reasonable. A pair of Prologue 7s will set you back $2699 and there are now some affiliate dealers around the country, so it might be a bit easier to find them in your hood. You can spend the 100 bucks you would have used on shipping to buy some more records! Pricing is the same at Upscale or an affiliate dealer.

Set Up and Burn In

The ProLogue 7s popped right out of the box and only required a few days of break-in to sound their best. 50 hours max. and they will be at their full potential, though they will sound pretty good after an hour. The initial break-in was done with stock power cords and tubes before we started tweaking a bit.

Most of my test listening was done with digital as a source, split between the Ah! Tjoeb 4000 player on its own and the rest using the AT4000 as a transport and the outstanding Bench-mark DAC-1. (Also in this issue) I also spun some LPs with my Rega P25/Shelter 501/BAT VK-P5 combina-tion with excellent results. All system interconnects were DH Labs Air Ma-trix, along with the DH Power Plus AC cords on all three boxes. I felt that this was keeping in with the cost of this system, yet still provided better sound than the stock cords. I also borrowed a Running Springs Haley from my lo-cal dealer, which also made a dramatic improvement in the system in terms of noise reduction and improved tran-sient attack.

Power, Power, Power

Just like the difference between the stereo PL power amplifiers, the KT-88 equipped model has a bit beefier power supply and some upgraded

(continued)

TONEA NO.3 2 0 0 6

capacitors. Thanks to Prima Luna’s Adaptive Auto Bias, you don’t need to match output tubes, which makes operation reasonably priced and allows you to try a couple of other flavors of output tubes, to have the option of tuning the sound to your taste a bit.

In addition to the adaptive auto bias, the tubes also have a soft start feature, which should contribute to long output tube life. Our ProLogue 1 has two years on it now, with almost continuous use at music editor NB’s house with not as much as a burp.

When you use a moderate efficiency pair of speakers, the monoblocks really sing. If you have a pair of Vandersteens or something else with about an 86db sensitivity, you will really love this pair of amplifiers. I also heard the monoblocks at CES along with the outstanding ACI Sapphire speakers which feature an 85db efficiency. Once I got a pair for review, the monos weren’t here yet and I started the review with the PL 5 amplifier. While this was fine for Miles Davis, I just couldn’t crank the Sapphires with 35 watts as much as I would have liked.

Once the monoblocks got here though, it was a different story. Now when I wanted to wind out Deep Purple’s Made In Japan, I was in business! Ritchie Blackmore’s lead solos had some guts and were well separated from the keyboards. Everything had that last bit of dimension that only comes with power. Everything that sounded good with

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the stereo amplifier, sounded GREAT with the monoblocks.

Keep in mind that these are not just the stereo amplifiers with another pair of output tubes added in parallel. The input circuit has been modified somewhat (see the Upscale Audio website for a full description) and the power supply beefed up as well. If you look close, you will also notice a 2-ohm tap on the speaker outputs.

Kevin Deal mentioned that he was surprised checking out some of the audio forums and seeing what people were connecting these amplifiers up to; Martin Logans, Magnepans, etc., so I had to give them the ultimate test, my Apogee Calipers. These have to be one of the most difficult speakers to drive and has the potential of turning your amplifier to a puddle of goo in a hurry. I made Jean get the fire extinguisher ready and hooked them up, but there was no drama, just good music.

For what it’s worth, the ProLogue 7s played just as loud as my McIntosh solid state amplifier that is rated at 200wpc. This is a VERY impressive little pair of amplifiers.

A Small Detour

As I mentioned earlier in this and my other PL review, thanks to the Adaptive Auto Bias, you can change the output tubes for different effect and system tuning. If you want dreamy midrange, switch to a set of EL-34s. (Might be really nice for driving a pair of Quads) The stock KT-88s are very good and a good all around compromise, but my favorite tube in this amplifier is the 6L6GC. It gives these amplifiers a bit warmer, more vintage character, almost like a pair of modern MAC 30s. (That won’t ever require service) While I found this combination dreamy with most speakers, it will really help tame a set of overly bright tweeters. I don’t measure gear for output yet, but it did seem like the 6L6s had just a touch less power than the stock KT88 tubes.

ThE VERDIcT

The ultimate question, is twice the power and a bit more refinement worth an extra $1300? No question about it! If you can only afford the stereo amplifier, I won’t call you a bad Smurf, but if you can scrape up the extra cash, go for the monoblocks, you’ll be glad you did. l

IMPoRTER

Upscale Audio 2504 Spring TerraceUpland, CA 91784909-931-9686www.upscaleaudio.com

PERIPhERAlS

line Stage PrimaLuna ProLogue 3, Modwright Instruments 9.0 SWLDigital Source Ah! Tjoeb 4000 CD player and Benchmark DAC-1Analog Source Rega P25/Shelter 501, BAT VK-P5, Teac A-4300

Speakers ACI Sapphire XL, Vandersteen 2Ce Signature, Apogee Caliper

cables DH Labs Power Plus AC cords, DH Revelation interconnects, DH Labs Q-14 Speaker Cables, Cardas Golden Presence Digital interconnect

Power conditioningRunning Springs Audio Haley

FAVoRITE TEST TUNES

Deep Purple Made in Japan, LP (Warner Bros)Richard Thompson From Parlour Ballads, LP (Diverse)cat Power The Greatest, LP (Matador)Death cab for cutie Plans, CD (Barsuk)Al DiMeola Land of the Midnight Sun, LP (Columbia)

Van halen Van Halen, CD (DCC)

ProLogue Eight Reviews

www.Stereophile.com, July 2008 105


Fred Kaplan & John Atkinson

PrimaLunaProLogue EightCD PLAYER

DESCRIPTION Single-box, fixed-output, remote-control CD player with tubed output stage, Super-TubeClock to minimize jitter, and SoftStart circuit for extended life of tubes. Tube complement: two 5AR4 rectifiers, two 12AX7, two 12AU7, subminiature triode in SuperTube-Clock circuit. Analog outputs: 1 pair (RCA). Digital outputs: S/PDIF on coaxial (RCA) and optical (TosLink). Frequency response: 20Hz–20kHz, ±0.5dB. Channel separation: 90dB at 1kHz. Maximum output level: 2V, ±3dB. Signal/noise: >96dB. Dy-namic range: 120dB. Distortion and noise: <–70dB. Power consump-tion: 50W.DIMENSIONS 15.5" (395mm) D by 11" (280mm) W by 7.5" (190mm) H. Weight: 25.4 lbs (11.5kg).SERIAL NUMBER OF UNIT RE-VIEWED 07051211.PRICE $2495. Approximate number of dealers: 14. Warranty: 2 years, limited to original owner; 6 months on stock vacuum tubes.MANUFACTURER Durob Audio BV, PO Box 109, 5250 AC Vlijmen, The Netherlands. Web: www.primaluna.nl. US distributor: PrimaLuna USA, 2504 Spring Terrace, Upland, CA 91784. Web: www.primaluna-usa.com.

There’s a retro, Heathkit vibe to the curiously capitalized PrimaLuna ProLogue Eight CD player: a shelf of glowing tubes and a chunky transformer case perched atop a plain black chassis. But on closer inspection, it seems there’s much more going on here. The chassis is made of heavy-gauge steel, with (according to the manual) a “five-coat, high-gloss, automotive finish,” each coating hand-rubbed and -polished. The tube sockets are ceramic, the output jacks gold-plated.

Inside, separate toroidal transformers power each channel. Custom-designed iso-lation transformers separate the analog and digital devices, to reduce noise. The power supply incorporates 11 separate regulation circuits. The output stage is dual-mono with zero feedback. Audio-handling chips include a Burr-Brown SRC4192 that upsamples “Red Book” data to 24-bit/192kHz, and one 24-bit Burr-Brown PCM1792 DAC per channel. Only the tiny silver control buttons (on the other-wise hefty faceplate of machined aluminum) betray a whiff of chintz.

In the early days of CD, a few tube-powered models came on the market; the idea was that the dimensionality and warmth of tubes would drape a cud-dly blanket over digital’s flat harshness. Digital has come a long way since then, and in any case the tubes in the ProLogue Eight aren’t about smoothing over; they are, or purport to be, about greater accuracy. Not only is the Eight powered

STRP-080700-PrimaLuna.indd 105 5/7/08 7:07:33 PM


P R I M L U N A P R O LO g U E E I g h T

by a pair each of 12AX7, 12AU7, and 5AR4 tubes; its internal clocking de-vice is a mini-triode tube instead of the solid-state oscillator found in most CD players. The claim is that a tube clock introduces less noise and jitter into the CD drive and the DAC chip, resulting in superior detail, dynamics, and mu-sicality. I have no idea whether there’s any technical basis for this claim. Nor could one judge simply by listening, without taking out the triode-based circuit, inserting a conventional oscilla-tor, and noting the difference (if any).1 Still, based on what I did hear, I suspect there might be something to it.

Fred’s setupI connected the PrimaLuna to the Krell FBI integrated amplifier, which in turn

fed the Verity Audio Parsifal Ovation speakers. Nirvana cables were used throughout. The PrimaLuna comes with a cage to cover the tubes, but I lis-tened with the cage removed, mainly because it looked nicer. (I didn’t notice any sonic difference.)

A note, perhaps, about quality control. The tubes are said to last 10,000 hours. (They’re warranted for six months.)

But on my review sample, long be-fore that time span, one of the 12AX7s went bad—one channel suddenly sounded fuzzy with occasional crack-ling, a problem fixed by replacing the tube. Also, once, when I lifted the front of the player a few inches to place be-neath it a Black Diamond Racing Cone (without turning the player off), one of the 5AR4 rectifier tubes started to flare. These instances may have been flukes; tubes are sometimes troublesome.

Speaking of those cones, they made a substantial sonic difference, more so than with most electronic gear. With-out the cones, bass sounded consider-ably flabbier and transients less crisp. I noticed this in what was as close to a double-blind experiment as a person can conduct by himself. After listening


I examined the PrimaLuna ProLogue Eight’s measured behavior mainly using Audio Precision’s top-model SYS2722 system (see www.ap.com and “As We See It” in the January 2008 issue, www.stereophile.com/

asweseeit/108awsi), as well as our Audio Precision System One and the Miller Audio Research Jitter Analyzer for some tests. As always, I experimented with the grounding between the player under test and the test set to give the lowest level of measured hum (see later).

The ProLogue Eight’s error correction was one of the best I have encountered. While its digital output flagged errors when the gap in the data spiral on the Pierre Verany Test CD reached 2.5mm in length, the player’s output didn’t mute, and the sound of the 500Hz tone remained continuous. It finally muted when the data gaps reached 3mm in length. This is extraordinarily good performance.

The PrimaLuna’s maximum output level at 1kHz was 2.13V, this 0.55dB above the CD standard’s 2V. The output preserved absolute polarity; ie, was non-inverting. The player had a significantly higher output impedance than the norm, ranging from 2.7k ohms in the treble

and midrange to an extraordinary 12k ohms at 20Hz. This player really does need to be used with an amplifier having an input of 50k ohms or more if the bass is not to sound a little lightweight. Many solid-state preamplifiers will not really be compatible with the ProLogue Eight; fortunately, PrimaLuna’s ProLogue Three preamp has an input impedance of around 100k ohms in the bass and midrange. However, I believe that this high output impedance was the reason I felt the ProLogue sounded lean with the Parasound Halo JC 2 preamplifier, which has an input impedance at low and midrange frequen-cies of 27k ohms. By contrast, Fred Kaplan’s Krell FBI amplifier has an unbalanced input impedance of 200k ohms, which is perfect for use with the PrimaLuna CD player.

Even so, with the Audio Precision System One’s 100k ohm input impedance, the PrimaLuna’s low-frequency response began to gently shelve down below 200Hz, reaching –0.5dB at 45Hz and –1dB at 18Hz (fig.1, top pair of traces). This will not be enough to make the play-er sound lightweight or lean, but it might lead to a feel-ing of improved low-frequency definition. At the other

Fig.1 PrimaLuna ProLogue Eight, frequency response at –12dBFS into 200k ohms, CD data (blue left, red right; 2dB/vertical div.).

Fig.2 PrimaLuna ProLogue Eight, 1/3-octave spectrum with noise and spuriae of dithered 1kHz tone at –90dBFS with 16-bit CD data (right channel dashed).

1 PrimaLuna’s website is bereft of any details about the SuperTubeClock circuit, and a white paper I had been promised by PrimaLuna engineer Marcel Crouse had not materialized by the time this review went to press. In theory, there should be no change in the behavior of an oscillator circuit due to the nature of the active device, other than the higher available gain from solid-state devices allowing a higher Q, or Quality Factor. Looking at the circuit board, there is a crystal directly adjacent to the miniature triode, so I assume the tube is used in what would otherwise be a conventional crystal oscillator circuit. —John Atkinson




end of the spectrum is a slight rise in top-octave output. With pre-emphasized CD data (fig.1, bottom traces), the ProLogue Eight offers the not uncommon depression in the treble. As a result, the player will sound a little mel-low on the few pre-emphasized discs that have been released. Channel separation (not shown) was better than 100dB in both directions in the upper midrange, but dropped a little at the frequency extremes.

To maintain historical continuity with past Stereo-phile reviews of digital components, I assess resolution by sweeping a 1/3-octave bandpass filter from 20kHz to 20Hz while the product under test decodes dith-ered data representing a 1kHz tone at –90dBFS. The resultant spectrum for the ProLogue Eight is shown in fig.2; while the left- and right-channel traces peak at –90dB, large peaks can also be seen centered at 60 and 180Hz, and a small one at 300Hz. As mentioned earlier, I experimented with the grounding between the PrimaLuna player and the Audio Precision test sets to give the lowest level of hum. However, the frequencies of the peaks in fig.2 suggest that they are due not to a ground loop but to magnetic coupling between the

power-supply transformer and the audio circuitry. Fig.3 shows the same spectrum, but plotted on a linear frequency scale and derived in a different manner: by applying a Fast Fourier Transform to time-domain data. The hum components can again be seen, and though harmonic spuriae are absent, some stray, very-low-level tones are present.

Plotting the PrimaLuna’s linearity error with a 500Hz tone swept from –60dBFS down to –120dBFS gave the traces shown in fig.4. The increasingly positive error below –90dB is due to analog noise. The ProLogue Eight’s reproduction of an undithered 1kHz tone at exactly 90.31dBFS was good, with the three DC voltage levels clearly visible (fig.5). However, some higher-frequency analog noise is present, leading to more jagged-looking traces than usual. In addition, the low-frequency power-supply noise overlays the left- and right-channel traces and moves them apart. It is fair to note that I couldn’t hear this AC supply hum from my listening chair at normal playback levels, but I could hear it when I turned up the volume to rock-out levels with recordings having wide dynamic range, such as Attention Screen’s Live at Merkin Hall (Stereophile

for a while to a different CD player, I put the PrimaLuna back in the sys-tem but forgot the cones. It sounded worse (flabbier, less crisp) than I’d re-membered. Then I noticed the missing cones. I put them back underneath, tips down, et voilà! Back to normal.

Fred on SoundWhat was normal for the ProLogue Eight? I’m tempted to say, “About what one would expect of a $2500 CD play-er powered by tubes.” Actually, it was better. The good things we’ve grown accustomed to hearing from tubes were all there: gorgeous midrange, sweet strings and saxophones, lifelike female singers, a soundstage with acres of depth. The deficiencies common to budget-priced tube units were there,

too—tepid bass, rolled-off highs—but not nearly to the degree you might ex-pect. Or, to the extent they were there, they were handled or offset in ways that made them less audible, certainly

less objectionable. I think this is where that triode clock comes in—or, at least,

some design feature that yields the same alleged effect.

One good test of bass, as I’ve noted elsewhere to the point of (some read-ers’) exhaustion, is the first minute

of David Zinman and the London Sinfonietta’s recording of Górecki’s

Fig.3 PrimaLuna ProLogue Eight, FFT-derived spectrum of 1kHz sinewave at –90dBFS into 200k ohms (blue left, red right; linear frequency scale). Fig.4 PrimaLuna ProLogue Eight, linearity error.

ThE gooD Things wE’vE gRown ACCusTomED To hEARing fRom TUBES WERE ALL ThERE: goRgEous miDRAngE, swEET sTRings AnD sAxo-PhonEs, LifELikE fEmALE singERs, A sounDsTAgE wiTh ACRES OF DEPTh.



110 www.Stereophile.com, July 2008

STPH018-2). By contrast, the Benchmark DAC 1 was deathly quiet at the same volume setting.

I had been warned that the PrimaLuna ProLogue Eight would show an increase in distortion with con-tinuous tones approaching 0dBFS. PrimaLuna’s design engineer in Holland, Marcel Crouse, says that this is due to saturation in the 12AX7 input tube. This “may seem odd in this time and age of vanishing low distortions and noise figures,” he explained, “but we think that the real gain in sound quality is largely obtained elsewhere. Not that we purposely neglect harmonics and static noise, but we think that, when they are so benign as to be essentially inaudible because music itself is full of lower-order harmonics and hiss (such as tape hiss or ambient hall noise), we’d better concentrate on distor-tions that generate entirely new frequencies that are not present in the musical instrument at all in the first place—distortions that shift harmonics in phase, which degrade attacks and dynamics; and noise modulation that impairs transparency, focus, and imaging—all arti-facts that we believe are far more seriously destroying the quality of the reproduction and the fun of listening to well-recorded good music.”

Fair enough. However, I measured fairly high distortion with a maximum-level 1kHz tone driven into 100k ohms, the second harmonic lying at –36dB and the third at

–43dB, with many higher-order spuriae visible. The situ-ation was similar at low frequencies. Reducing the signal level to –3dBFS dropped these harmonics by 6dB or so (fig.6), but not until I reduced the signal level to –10dBS did all the harmonics drop to –50dB (0.3%) or below (fig.7). The 60Hz and 180Hz hum components can also be seen in figs. 5 and 6.

Concerned that we might have been sent a faulty sample, I contacted Marcel Crouse, who reassured me that my measurements were typical. “You saw the same thing in the PrimaLuna ProLogue Three preamplifier [reviewed in December 2006]. The tube stage of the ProLogue Eight is the same [as that of the Three] save for the volume control. . . . Also, the 60Hz hum seems to be consistent; I measure –86dB at 50Hz. (It seems to be the power transformer’s stray field.) So we may conclude that your review sample is not faulty.”

Looking at intermodulation distortion at maximum level, using my usual equal mix of 19 and 20kHz tones, each at –6dBFS, was, as expected from the earlier results, disappointing, with the 1kHz difference tone at –40dB (1%) and many other higher-order products pres-ent (not shown). Dropping the signal level by 10dB gave the spectrum shown in fig.8. (Ignore the rise in the noise floor above 15kHz, which is due to the noiseshaping I used to generate a 16-bit signal from a 24-bit original.)

Symphony 3 (CD, Elektra Nonesuch 79282-2), during which the double-basses sound out the melody in an oc-tave so low that, on some systems, you can barely hear them at all. With the PrimaLuna, I couldn’t hear the actual values of the lowest notes, but I could hear the attack of the bows and the har-monic overtones. In other words, I got a sense of the bass line; unless I’d heard this album on other, better CD players, I might not even have been aware that the bass was rolled off.

Similarly, at the start of “Mood Indi-go,” on Duke Ellington’s Masterpieces by Ellington (CD, Columbia/Legacy CK

87043), I couldn’t identify all the lowest notes that the bass player plucked, but I did hear the pluck. And since that pluck has a lot to do with the music’s rhythm, dynamics, and emotional drive, I’d rather hear a pluck without the precise note than vice versa. On James Carter’s tribute to Django Reinhardt, Chasin’ the Gypsy (CD, Atlantic 83304-2), I could hear the guitarist’s strummings, even if I couldn’t quite hear the full body of the guitar. On the Maria Schneider Jazz Orchestra’s Sky Blue (CD, ArtistShare AS0065), I didn’t hear the cymbal’s full shimmer, but I did hear the percussive edge of the drumstick hitting it. On

Lorraine Hunt Lieberson’s lovely disc of two Bach cantatas (CD, Nonesuch 79792-2), her slight sibilance on conso-nants—g, k, ch, and so forth—cut through distinctly. Without such clarity, sung words are unintelligible.

The ProLogue Eight didn’t get all the subtlest transients quite right. When Erik Friedlander rapidly plucks the cello on his wondrous solo disc, Block Ice & Propane (CD, SkipStone 371013742), a CD player like the Krell Evolution 505 lets you hear not only his most intricate fingerwork but also the relative thickness of each string and its resistance to his plucking. The Pri-

Fig.5 PrimaLuna ProLogue Eight, waveform of undithered 1kHz sinewave at –90.31dBFS, 16-bit data (blue left, red right).

Fig.6 PrimaLuna ProLogue Eight, spectrum of 1kHz sinewave at –3dBFS into 200k ohms (blue left, red right; linear frequency scale).





The difference tone lies at –54dB (0.2%) ref. the signal (–64dB in absolute terms), which is respectable. More important, all the other spuriae are well down in level, though a product can be seen at 23.9kHz, this due to a rather “leaky” anti-aliasing filter.

I used both the Miller Jitter Analyzer and the Audio Precision SYS2722 to examine the ProLogue Eight’s rejection of word-clock jitter. The two systems gave similar results; the spectrum produced by the Audio Precision is shown in fig.9. The jitter level was a fairly low 406.5 picoseconds peak–peak. More significant, the highest-level sidebands that can be seen either side of the central 11.025kHz tone in fig.9 lie at power-supply–related frequencies of ±60Hz and ±120Hz. Actual data-related sidebands were much lower in level; if it weren’t for the supply-related spuriae, the ProLogue Eight would have very good jitter rejection. I suspect that it is these supply-induced sidebands that led Fred and me to feel the ProLogue Eight’s upper bass sounded a little soft.

Summing up the PrimaLuna ProLogue Eight’s mea-sured performance is difficult, as some of the things it does wrong, such as the increasing distortion at levels above –10dBFS, will not be that audible with typical music—a distorted snare-drum peak sounds the same as a clean one. But I was concerned about the effect of the transformer-radiated hum. I was also bothered by the

very high output impedance at low frequencies, which will make system matching more difficult than usual.

—John Atkinson

maLuna didn’t. Then again, the Krell costs four times as much.

The ProLogue Eight’s shortcomings are more apparent with some recordings than with others. On the Lieberson disc, the double bass wasn’t distinguishable from the organ; that reedy sound of the organ’s pipes was obscured by sounds of a similar pitch. And while the depth of the recording venue was nicely captured (the oboe seems to be way back there), there wasn’t much sense of air between the instruments from side to side.

And, back to the Górecki, in the mid-dle of the first movement, when the basses growl right before the crescendo,

the PrimaLuna didn’t let me hear the growl. Fast transients and accurate over-tones can go only so far in disguising an absence of truly deep bass.

Dynamic range was compressed a bit, but peaks weren’t distorted or clipped; it was more like someone slightly easing up on the pedal. The high octaves were also rolled off a bit (hence the shortage of air), but the rolloff was smooth; there was no sense of a brickwall filter, no harshness.

—Fred Kaplan

Comparisons from John AtkinsonThere are two important questions to

be asked about a midpriced CD player like the PrimaLuna ProLogue Eight: 1) Does it offer sufficient sonic improve-ment over less-expensive products to be worth considering at all? and 2) does it approach the sonic performance of more expensive components, making its recommendation a no-brainer?

As Fred Kaplan admits above, his primary reference for his audition-ing of the ProLogue Eight was the very much more expensive Krell 505 SACD player. (There is an inevitable conflict between a reviewer’s need to have as a long-term reference a com-ponent whose sound he is intimately

Fig.7 PrimaLuna ProLogue Eight, spectrum of 1kHz sinewave at –10dBFS into 200k ohms (blue left, red right; linear frequency scale).

Fig.8 PrimaLuna ProLogue Eight, HF intermodulation spectrum, 19+20kHz at –10dBFS peak into 200k ohms (blue left, red right; linear fre-quency scale).

Fig.9 PrimaLuna ProLogue Eight, high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz, 16-bit data. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz (blue left, red right).


112 www.Stereophile.com, July 2008

familiar with, and other components that are directly competitive with the product being tested.) The first of these two questions was left unan-swered, therefore. As I have a stable of players available for comparison, I stepped into the review.

I did a long series of comparisons be-tween the PrimaLuna and four digital sources that I know well: the Ayre C-5xe universal player ($5000), which has been my long-term reference since I bought a sample following Wes Phil-lips’ review in July 2005; the now-dis-continued Oppo DV-970HD univer-sal player ($149 when available), which WP enthusiastically reviewed in May 2007; the Pioneer DV-578A universal player ($150), one of which I bought a few years back to use as a low-priced reference (no review, though the Pio-neer chassis has been used as the basis for a number of high-end universal players, and WP used it as a reference in his Oppo review); and the Bench-mark DAC 1 USB D/A converter/headphone amplifier ($1275), which I reviewed in January 2008. The Bench-mark is a superb-sounding DAC and a bargain at its price (and even more so at $975, which is what it costs without the USB input). Given that it will pro-duce close to Class A CD sound for not much more than a kilobuck when used with an inexpensive player such as the Oppo2 or Pioneer, I feel that the Benchmark DAC 1 sets the bar for players that cost significantly more.

All comparisons were performed matching the sources’ output levels to within 0.1dB at 1kHz. For the player comparisons, I used duplicate CDs playing synchronously on both play-ers. For the comparisons with the Benchmark, the DAC was driven via a 1m length of AudioQuest OptiLink-5 from the PrimaLuna’s digital output.

I also used the ProLogue Eight as my primary CD player for quite a while, but became increasingly dis-satisfied with a lean tonal balance. (I also didn’t like the slowness of the Pri-maLuna’s disc tray, but that’s a more personal thing.) I stopped using the player to examine its measured per-formance, which revealed the reason for the tonal problem: the Parasound Halo JC 2 preamplifier has a moder-

ately low input impedance of 27k ohms in the midrange and bass; the ProLogue Eight’s output impedance is 2.7k ohms in the treble and midrange, but rises to a very high 12k ohms at 20Hz. The volt-age divider formed by this value and the input impedance of the Parasound pre-amp will shelve down the low bass by up to 2.4dB. This is not much in abso-lute terms, but in my system and room it was enough to unbalance the Pri-

maLuna’s sound. Crestfallen, I replaced the Halo JC 2 with the Mark Levinson No.380S, which has an input imped-ance of 100k ohms. All the remaining auditioning and all the comparisons were performed with this preamp.

Once that had been sorted out, my opinion of the PrimaLuna ProLogue Eight was very positive, in that it did one thing superbly well: it threw the widest, deepest soundstage from CDs that I have experienced with any player. Perhaps even more important, individ-ual images within that stage were clear-ly delineated, with a palpability more akin to what you get from SACD (or LP). At the beginning of April I record-ed Bob Reina’s jazz group Attention Screen live at Otto’s Shrunken Head, a Manhattan tiki bar, using an ORTF pair of cardioid mikes. The individual drums of Mark Flynn’s kit were clearly positioned farther toward the back of the stage than the bass guitar, keyboard, and guitar. But it was the palpability of the offstage noises, such as the pinball machine in the adjacent bar area, and the sounds of members of the audience talking between songs, that impressed me when the resultant CD was played back on the ProLogue Eight. In this, the Dutch player outperformed even the Ayre C-5xe!

Compared directly with the Ayre, however, the ProLogue Eight didn’t go quite as deep in the bass, nor was its up-per bass quite as well defined. Sound-ing a little soft, the upper harmonics were slightly emphasized, to the detri-ment of the fundamental and the sec-ond harmonic—not unpleasant, but not strictly accurate, either. Kick drum on Attention Screen’s recording at Otto’s had a slightly better-delineated “thud” through the Ayre. Overall, the solid-state player had a more delicate but more laid-back upper midrange than the tubed one, which proved a more synergistic match with the forward-balanced Avalon NP 2.0 speakers.

The PrimaLuna did sound more dy-namic overall, but on the channel-iden-tification tracks on Editor’s Choice (CD, Stereophile STPH016-2), my bass guitar had a touch too much “bite” to its sound than with the Ayre. It’s fair to note, however, that the differences between the two players were not night-and-day.

Turning to the other end of the price spectrum, my next comparisons were with the Oppo DV-970HD. Consistent differences were easier to hear. The cheap player dried up the

ASSOCIATED EQUIPMENT

FRED KAPLAN’S ASSOCIATED EQUIPMENTDIgITAL SOURCES Krell Evolution 505 SACD player, Simaudio Moon CD 5.3 CD player.INTEgRATED AMPLIFIER Krell FBI.LOUDSPEAKERS Verity Audio Parsi-fal Applause.CABLES Nirvana.ACCESSORIES Bybee Signature Model Power Purifier, Monster Cable AVS2000 voltage regulator, Black Diamond IV Racing Cones. —Fred Kaplan

JOhN ATKINSON’S ASSOCIATED EQUIPMENTDIgITAL SOURCES Ayre C-5xe, Pioneer DV-578A, Oppo DV-970HD universal players; Benchmark DAC 1 USB D/A converter.PREAMPLIFIERS Parasound Halo JC 2, Mark Levinson No.380S.POWER AMPLIFIERS Mark Levinson No.33H.LOUDSPEAKERS PSB Synchrony One, Epos M16i, Avalon NP Evolu-tion 2.0, Magico V3.CABLES Digital: Kimber Illumina-tions Orchid AES/EBU, AudioQuest OptiLink-5 S/PDIF. Interconnect (balanced): AudioQuest Cheetah, Ayre Signature Series. Interconnect (unbalanced): Linn, Canare. Speak-er: AudioQuest Kilimanjaro. AC: PS Audio Lab, manufacturers’ own.ACCESSORIES Target TT-5 equip-ment racks; Ayre Myrtle Blocks; ASC Tube Traps, RPG Abffusor panels; PS Audio Power Plant 300 at 90Hz (sources, preamps), Audio Power Industries 116 Mk.II & PE-1, APC S-15 AC line conditioners (not power amps). AC power comes from two dedicated 20A circuits, each just 6’ from the breaker box, a power amplifier plugged into each. —John Atkinson

2 The big disappointment for me with the Oppo used as a transport was that its digital output truncates 24-bit DVD data to 16 bits. This doesn’t affect its rec-ommendation as a CD transport, however. —John Atkinson




recorded acoustic a little, sounding deader as a result. The subtle manner in which Don Fiorino’s electrified lotar lights up the hall on “Mansour’s Gift,” from Attention Screen’s Live at Merkin Hall (CD, Stereophile STPH018-2), was more effectively conveyed by the PrimaLuna. In the orchestral arrange-ments of Gershwin’s Preludes for Piano on Editor’s Choice, the soundstage was flatter and drier through the Oppo, which also rendered the bass guitar and lower-pitched tom toms as sounding more “hummy.” The occasional rustle and tick from the audience in the live recording of the Mozart Flute Quartet on that CD was less well delineated through the Oppo, less identifiable as offstage noise than via the PrimaLuna, and the image of the solo flute was wider and slightly less stable.

The Oppo did have a smooth if rath-er bland balance that went some way toward taming the Avalon speakers’ forward upper midrange. But its sound was curiously uninvolving overall.

I had a different experience from Wes Phillips with the Pioneer when I com-pared it to the Oppo. Wes had written that he found that the Pioneer’s high frequencies sounded less smeared than the Oppo’s, though he felt both players had disappointing lows. Yes, the low frequencies were very similar, but I felt the Pioneer both to have a little more top-octave energy and a more involv-ing sound, with a better-fleshed-out midrange. The piano on my recording of Robert Silverman performing Liszt’s Liebestraum on Editor’s Choice was more organic in its presentation, by which I mean the percussive attack to the

notes was better integrated with the following body of the tone. How-ever, the Pioneer still didn’t begin to approach the palpability of the PrimaLuna player in this respect. Its soundstaging was flatter, and it lacked both the dynamics and the sense of top-octave ease that charac-terized the ProLogue Eight.

It was against the Benchmark DAC 1 that the match became more equal. Not only did the standalone DAC have a more delicate, more articulate midrange and better-de-fined low frequencies, its soundstag-ing was far closer to the PrimaLu-na’s than those of the inexpensive universal players had been. The im-age thrown by the Benchmark was wider than that of the ProLogue Eight, with very slightly more top-octave air, though the tubed player

still did better when it came to ultimate image depth and sense of bloom.

The ProLogue Eight had more force-ful dynamics, the Benchmark blacker blacks. But as with the Ayre compari-sons, and again putting to one side the enormous soundstage thrown by the tubed player, I’m not talking about enormous differences here. Which pre-sentation will be preferred will depend very much on the listener’s taste in sound and music, as well as on the rest of the components. The Benchmark would be the better choice in systems that are balanced a bit on the forward side; the PrimaLuna would be best in systems that tend to be laid-back.

So, to answer my two questions: yes, the PrimaLuna ProLogue Eight3 definitely offers a considerable step forward in sound quality compared to entry-level players; and yes, when it comes to soundstaging at least, it does compete on the highest level.

—John Atkinson

Fred Kaplan Sums UpIn sum, the PrimaLuna ProLogue Eight is a very fine CD player for the money. Its designers seem keenly aware of the machine’s strengths and weaknesses, and they know how to maximize the former and finesse the latter. —Fred Kaplan

3 PrimaLuna offers two upgrades for the ProLogue Eight, each comprising a plug-in printed circuit board with the standard NE5534 op-amp chips replaced with unidentified chips offering lower noise and a much higher slew rate. I will report on the effect of these upgrades in a “Follow-Up.” —John Atkinson

The two 5AR4 rectifier tubes sit at the back, the signal tubes at the front.


pagina 1 van 4Print Pages

10-6-2008http://editions.pagesuite.co.uk//PrintPages.aspx?pagenumbers=1,26,27,29&editionid=5...

TEST: VACUUM-TUBE CD PLAYER

PrimaLuna

ProLogue Eight A R T I C L E B Y : L E F T E R I S X E N O S

MoonlitWhen a company not only wins the “best buy” title, but maintains it for a series of years, it is obvious that they have a well hidden and successful recipe, capable of hypnotizing everybody and creating a sea of enthusiastic supporters. This is PrimaLuna, and this is the debut on the world of their not entirely digital reproduction.

How can anybody forget the hype created by PrimaLuna approximately three years ago, when they managed to make the entire world literally talk about them and their exquisite vacuum tube amplifiers? As far as I’m aware, they are one of the first companies able to trust a Chinese company with production and assembly, while keeping quality control, design and marketing to Western standards. The result? A series of vacuum tube amplifiers that could sell for twice as much money or more, and still be on top in comparative tests, whether it is in our magazine, or in other specialized magazines throughout the world. Would I be exaggerating to say that the new generation of Hi-Fidelity enthusiasts, avidly looking for an affordable alternative solution for sound, got introduced to the world of vacuum-tubes through PrimaLuna? In any case, the point is that PrimaLuna has earned our trust and appreciation, two very valuable assets, which are extremely useful in this industry, especially now that they venture into in the world of digital reproduction. Therefore, please welcome the ProLogue Eight CD player, a worthy child of the famous ProLogue family. Obviously, you will have to be prepared for technological breakthroughs and fresh ideas, since the word “conventional” has been erased from the PrimaLuna’s vocabulary.

FROM THE EARTH TO THE MOONAt first glance, the ProLogue Eight is not very different from the other ProLogue models. With the output tubes placed in the front, and the sizable power supply transformers located immediately behind the tubes, the misunderstanding is bound to happen. Its digital nature is revealed in all its glory as soon as we get closer to the anodized aluminum faceplate, and find the existence of the ProLogue Eight’s loading tray, LED display, and four control buttons of the transport. In general, the ProLogue Eight’s build is as sturdy any other ProLogue component, with plenty of attention paid to details. Now, there

IMPORTED BY

are a lot of you, and for good reasons, who will wonder about the relation between the oldest amplifying element (the tube) and a digital music source. Here is the explanation: immediately following the digital-analogue converter (DAC) of any CD player is the “analogue section.” There, among others, the analogous deep-pass filter is installed, which aims in eradicating the sampling frequency and any distortion signals the DAC produces. Immediately after that, there is another stage, called the “isolation stage,” entrusted with the task of isolating the player from the preamplifier, while maintaining the correct adjustment of composite resistances in order to achieve the maximum voltage transfer. Usually, quality operational amplifiers are used for this task, while certain more exotic solutions will also use tubes. The ProLogue Eight belongs to the second category. As a result, there is a single 12AX7 and 12AU7 in each channel which make up the output stage. The two larger tubes in back are 5AR4 tubes which serve as the rectification stage in the power supply unit and are accompanied by a pair of Nichicon capacitors. In addition, it should be stated that the design of the player is dual mono.

At the heart of the digital section we find two Burr-Brown chipsets: the SRC-4192, which performs the upsampling of the digital signal received from the transport, which is then sent to the PCM-1792 converter, at a 192 kHz/24 bit form. Then, the converter applies 8x oversampling by using an integrated digital filter.

The interesting features do not stop here. PrimaLuna has applied their own exclusive clocking device: the SuperTubeClock™. This clocking device replaces the typical solid state oscillator with a mini triode vacuum tube, whose oscillation frequency re-clocks the digital signal in both the transport exit and the DAC. PrimaLuna promises an extremely low amount of clock jitter, which as a result, leads to a better transitional response and increased musicality.

What you see is Primaluna’s solution for low clockjitter.It refers to an approach with code name “SuperTubeClock” which replaced the typical solid state oscillator with a little triode tube which with his frequency oscillation reclocks the output of the sample rate converter and the dac.

BORN TO WINI must admit that I was extremely anxious to evaluate the sound of the ProLogue Eight. After experiencing the overthrows and upheavals Primaluna is capable of causing, I wanted to define its classification with as much accuracy as possible. For this reason, I requested from Hegel the CD4A Mk2, which is currently the best player in the €1,500 – €3,000 category in our magazine’s tables. Of course, I did not suffice to that, since I already had warmed up in the rack two top reference players: the Sony SCD-XA900ES, and the expensive Nagra CDP. From there on, the Nagra PL-L vacuum-tube preamplifier0 supplied the signal to the YBA amps of our reference system, which then powered the large and very revealing speakers ATC SCM70.

I am a person of the first impressions, which happen to be not only vivid, but durable in time. For this reason, I started my musical cohabitation with the PL8 (it was sent burned in with approximately 500 hours) relieved from the tension of the comparative hearing, which would follow later on. For a significant amount of time, more than scheduled initially, I enjoyed listening to music. The ProLogue Eight manages to win the experienced listener with the highly liquid, musical, liberated and sufficiently realistic character. It’s missing nothing: neither the extent, or articulation, or analysis, or dynamic consistency. It is a complete result, enriched with finesse and a sophisticated atmosphere. As a result, those of you who are looking for a quality player with a variety of audiophile characteristics, and do not wish to trouble yourselves too much, should stop reading here and purchase a ProLogue Eight as soon as possible. I guarantee you that you will enjoy it. However, if you are an even more avid enthusiast and wish to look further, I’m certain that you will evaluate the amount of conclusions that resulted from the competition with the top players stated above.

The one thing I have to state, with as much seriousness as I can afford to, is that the ProLogue Eight held its own with the competition imposed by the two reference players (by Sony and Nagra),

by bridging the obvious price gap. The Sony and Nagra bettered the PrimaLuna, but only by a very narrow margin, hard to be identified by the average audiophile. In areas such as analysis, presentation of micro details and vivid representation of melodic lines, the Nagra CDP is top game, with a noteworthy competition imposed by Sony, despite the slight lack of mass presented.

The most realistic comparison was made with Hegel, where the result was the verification of two completely opposite philosophies. Choose between exuberance, sharp dynamic ranges and rich musicality (PrimaLuna), against pureness, frightening directness and “pointy” sibilant features (Hegel). Some will love the former while others may love the latter. One thing that is certain is that PrimaLuna enters the world of sources with flying colors, continuing a tradition stating that it is one of the “best buy” companies in the market. Well done.

Output Level: 2V (+/- 3 dB)

Frequency Response: 20Hz-20kHz (+/- 0.5 dB)

S/N Ratio ≥96dB

Outputs: 1xLine out analog, 1xCoixial, 1xOptical

Tube Complement: 2x5AR4, 2x12AX7, 2x12AU7

Dimensions: (DxHxB): 38x30,5x46,5 cm

Weight: 11,5 kg

SPECIFICATIONS

TEST: VACUUM-TUBE CD PLAYER

ProLogue PremiumIntegrated Amplifier &

CD Player Reviews

7/8-09juli/aug.NL € 4,95BE € 5,45

H E T M A G A Z I N E M E T ‘ M E E R ’

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ProLogue Premium

PrimaLuna901

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ACTIE ELEKTRONICA SERVICE KRIMPEN

WERELDPREMIÈRE!

PrimaLuna

PRIMALUNA PROLOGUE PREMIUM INTEGRATED AMPLIFIER AND CD PLAYER

PrimaLuna founder Herman van den Dungen is well-known for his original vision and working method

concerning the audio community. He is a true master in fi nding inventive “out of the box” methods of

offering existing or original products to enthusiastic customers. A prime example of this ingenuity starts

when a stylus company is not willing to supply their products to a fl edgling (at the time) company, Durob

Audio. Herman doesn’t think twice, and approaches another stylus manufacturer where he was taught

to replace elliptical diamond tips with then “modern” Shibata diamondtips. Herman is soon considered

as the man in audioland who fi nds a solution for every challenge. (It was Robin Hood who stated “Every

challenge has a solution; if there is a way, we will fi nd that way”). Today Herman is quite busy with

organizing affordable production in China of beautiful and very high-quality audio products designed

by him and its team. In this issue of Music & Emotion we have the world’s fi rst look at the brand-new

ProLogue Premium Integrated Amplifi er and CD player!

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The name PrimaLuna is Italian, and means “fi rst moon”. It was actually Her-man’s grandmother who indirectly came up with the name. Herman’s grandfa-ther (the fi rst Herman van den Dun-gen) was given the nickname “Maantje” by his wife, which means “Little Moon”. So, take the fi rst Herman, combine with moon or Little Moon you eventually get “fi rst moon” or in Italian: PrimaLuna! The primary goal of this brand is to create the greatest possible quality product for the lowest possible amount. In Her-man’s years of experience in audio, his greatest irritation has always been the disappointing reliability of many high-end products. To be able to realize his goal, he knew to surround himself by the best minds in the audio industry such as Marcel Croese (former Goldmund chief engineer), Jan de Groot (ex-Sphinx), and Dominique Chenet (ex-Jadis) make up his team, not to mention his network of distributors from around the world. After years of preparation, the fi rst Pri-maLuna product, the ProLogue One In-tegrated Amplifi er, entered the market in 2003. This fi rmly and compactly built tube amp is still available today and car-

na introduced the more luxurious Dia-Logue Series in addition to the relatively basic ProLogue Series. These products are superlative in every way, and have among other things a wider chassis with an eye-catching tube protection cover, better components at critical locations, larger power and output transformers, greatly improved voltage regulation and a full-function remote control. DiaLogue amplifi ers can even switch from triode to ultralinear via remote; a feature that is, as far as I know, unique to PrimaLuna!

ProLogue Premium series

After several years of successful sales, eventually it becomes necessary to re-new and improve the original ProLogue Series designs from 2003. The PrimaLu-na design team has not been asleep these past few years, so the new Pro-Logue Premium Series is far more than a simple update. When Herman person-ally delivered the two boxes, I was not immediately astonished by the weight. Tube products usually weigh more than their transistorized bretheren, especially because of the transformers. What did astonish me, however, was the looks of

ries a selection of quality components, including PrimaLuna’s own transform-ers, which are positioned in the middle of a precision hand-wired circuit. Like all PrimaLuna amplifi ers, the ProLogue One incorporates a push-pull ultraline-ar circuit, using four EL34 power tubes for 35 watts x 2 power output. The most striking component is PrimaLuna’s pro-prietary Adaptive AutoBias system, and a nearly 100% effective protection cir-cuit. It is due to these innovative circuits that PrimaLuna is perhaps the most in-fl uential product on opening the world of tube amplifi ers to a larger group of peo-ple, many of whom had been turned off of tube equipment because of reliability issues. With PrimaLuna’s unparalleled reliability, excellent sound quality and very affordable pricing of around 1,000 [in 2003], the ProLogue One took the audio community by storm. In the years after the release of the ProLogue One, the range has been steadily expanded with among other things a ProLogue Two integrated with KT88 power tubes; and some years later a very high-quality tube CD player with a tube-based clock, the ProLogue Eight. In 2005, PrimaLu- NEXT

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the design. I thought to myself, “Her-man, you said I was going to get the new ProLogue for review, not the more expensive DiaLogue!” As I continue un-packing, I keep thinking I am dealing a DiaLogue amp. Once I take a look at the front panel though, I know it’s the Pro-Logue Premium model. It is easy to con-fuse the two, even sitting next to each other the ProLogue Premium and Dia-Logue models do look a lot alike. Nev-ertheless, there are some easily per-ceptible differences. The fi rst and most notable comes immediately when you try to move them; the DiaLogue is at least about 10kg [22 lbs] heavier than the ProLogue Premium due to its larg-er transformers. The DiaLogue is also about 2 cm wider. There are more dif-ferences internally, but the fact remains that both models at fi rst glance look like two drops of water. Before I start off with my review, I think it is important to explain the new structure of the Pri-maLuna program; in September 2009, quite a bit is changing. The original Pro-Logue One and Two will be replaced by a single, technically updated ProLogue Classic integrated amp. The ProLogue Eight CD-Player will remain in the line as well. The remaining ProLogue mod-els will gradually be removed from the line up over the next two years. The new ProLogue Premium Series will cover all currently known models, but the cosmet-ic and technical designs will be all new. Instead of having a model One (EL34) and model Two (KT88) integrated, the two models will be combined into one: the ProLogue Premium Integrated Am-plifi er. The same approach is taken with the stereo and monoblock amplifi ers. The model Three preamplifi er becomes the ProLogue Premium Preamplifi er, and the model Eight CD-player becomes the ProLogue Premium CD Player.

ProLogue Premium

Integrated Amplifier

Once I had absorbed all of this informa-tion, I was interested in fi nding out what the new prices will be. The ProLogue Classic Integrated Amplifi er, which based on the original ProLogue Two with KT88 power tubes, keeps it’s same

retail price of € 1,650, in spite of sev-eral technical improvements. You can also purchase the ProLogue Classic integrated equipped with EL34 tubes € 1,450. The new ProLogue Premium Integrated Amplifi er with KT88 tubes retails for € 2,150 – considerably more expensive. The EL34 version sells for € 1,950. The DiaLogue Two retail price is € 2,400, still a fi nancial step up. When I began to carefully inspect my to-be-re-viewed ProLogue Premium Integrat-ed Amplifi er, I noticed an extraordinary beautiful product, at fi rst glance giving the impression of a product with a much higher price tag. The product has ex-traordinarily solid build quality, fi nished in a beautiful anthracite metallic hand-rubbed gloss paint. The volume and selector knobs turn very smoothly, and

both the ALPS volume and 5-source source selector switch are controllable with a very beautiful anodized aluminum remote. Two rubber O-rings at each end of the remote offer a nice touch, and help to protect your precious pieces of furni-ture. The tubecage has a smooth round shape and very solid construction, that can be easily removed if desired. The rear side exudes real high end fl air with its high-quality and well-spaced connec-tors; well maybe the speaker terminals are a bit close together, but offer both 4 Ohm and 8 Ohm connections. Re-moving the bottom plate reveals a sight that is a joy for they eyes, with plenty of hard-wired connections and some small PC boards for the autobias and various protection circuits. The ProLogue Pre-mium Integrated Amplifi er is sold with a

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choice of four KT88 or four EL34 power tubes, and four 12AU7 input and driver tubes. Though each tube proudly bears the PrimaLuna logo, they are from the Chinese Shuguang factory; one of the largest producers of new tubes in the world. As PrimaLuna purchases such a large quantity of tubes, they get fi rst choice out of all tubes produced. That is to say that, out of 1000 factory-selected and approved tubes, PrimaLuna selects 600 of the best, rejecting the rest and sending them back to the factory. That’s what we call serious quality control.

Technical changes

Thanks to the larger chassis of the new models, more space is available for in-stalling updated parts and no-compro-mise circuitry. The design team certain-

use them the way he wanted to. Happily I was able to test the original ProLogue along side the ProLogue Premium am-plifi er with the new tubes! Furthermore, the ProLogue Premium series use fast recovery diodes in the power supply, larger output transformers, and higher quality components are implemented in all vital areas in the circuit. The Adap-tive AutoBias system has been further refi ned, and the protection circuit has been improved to offer the most protec-tion possible: Bad tube indicator LEDs have been installed in front of each power tube to indicate a failing tube, and Output Transformer Protection that helps to protect the output transformers from catastrophic failure, even when no speakers are connected to the amp.

ProLogue Premium CD Player

Just like the Integrated Amplifi er de-scribed above, the original ProLogue Eight CD-player has now been integrat-ed into the more beguiling and larger chassis. Not only does it give the player a more robust appearance, but the add-ed space is well-used when installing the components, allowing for optimal placement to minimize noise and hum. The CD player weighs in at a substantial 17kg [37.5 lbs]. As with the amplifi er, the biggest internal change in the cd-play-er is the modifi cation of the input tubes, incorporating four 12AU7 tubes. Two 5AR4 rectifi ers carry over from its pred-ecessor, quite striking for a CD-player in this price-range, which according to Pri-maLuna offers considerable sonic advan-tages compared to standard solid-state rectifi er circuits. Also the SuperTube-Clock is quite remarkable with meas-urably improved properties over other clocks. PrimaLuna is the only company in the world to offer a clock design using a tube as the oscillator. The rest of the player has been executed in a very so-ber way. Beside the demure blue/green display and the transport drawer, you fi nd only four push buttons: Play/pause, stop/open, skip forward, and skip back. On the system remote control you fi nd some more functions, but don’t expect a repeat function or direct track choice, al-though the repeat function is hidden but

ly didn’t choose the easy route; the list of changes is pretty serious. Here they come the one after the other: The Pro-Logue Premium Integrated Amplifi er provides a switch on the right side of the chassis that adjusts the Adaptive Auto-Bias to optimize for for KT88 or EL34 power tubes. Next is the modifi cation of the input tubes that are used. Original-ly the ProLogue series used the tried-and-true combination of two 12AX7 in-put tubes and two 12AU7 driver tubes. In the ProLogue Premium products, the 12AX7 tubes have been replaced by 12AU7 tubes. This tube has lower dis-tortion values and larger linearity, as well as considerably lower amplifying factor, so low in fact that designer Mar-cel Croese had to design a new circuit around the 12AU7 in order to be able to

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still available! The backside provides the same high-quality RCA connectors as found on the amplifi er, as well as both coaxial and optical digital outputs.

Listening 1 - KT88 power tubes

Since my Integrated Amplifi er came standard with the KT88 power tubes, I decide to start with that confi guration. I was fortunate to have both a Classic (with the old tube confi guration) and a Premium, I decide to start playing with the former variant long enough to feel well prepared for the changes in the new Premium models. Only after I had made myself familiar–again–with the standard ProLogue model, I felt ready to test the Premium model. I kicked things off with the newest Andreas Vol-lenweider CD of Andreas Vollenweider Air (Noble 0196302CTT). The track “air dance” starts with gentle breathing, building to a large number of people sighing and panting louder and louder, until they eventually end up in a taste-ful apotheosis with fully accompanying instruments. It is a beautiful opening for a CD in the known atmosphere of pushing, pulling and especially swing-ing style like Vollenweider used to have on his very fi rst albums. The PrimaLuna started off well, immediately showing a

pleasantly sounding and stable sound-stage. The different instruments are eas-ily recognizable, while together with the harmonic tones of the electrical harp, they know how to melange themselves to one large organic image. Specifi cally the CD Player combines a remarkably large tonal richness with fl uid and spa-cious reproduction which is quite rare with CD players. It’s maybe a bit much to call this a reproduction of an analog turntable, but the ProLogue Premium CD player does stand apart from most others. The next CD is the well-known Breaking Silence from Janis Ian. From this already well-recorded album, I re-cently received a rare gold disc version from Analogue Productions (Capp027). When I played the track “Tattoo” the reproduction was intensively emotion-al and organic, yet a little less precise or defi ned than I am normally used to. Now it’s time to fi nd out what kind of dif-ference I can expect with the new tube confi guration. And what a difference it was! When I played the same track on the new ProLogue Premium amplifi er, I could hardly believe my ears. The dif-ference was astounding. There is a lot more air and the sound seemed more natural and holographic, far more than the original amplifi er. This new confi gu-

ration is a big step forward. Suddenly Janis Ian’s song lyrics and musical pa-rameters come together in an very tan-gible way. I am enthralled by the chosen tonal balance, which beautifully blends the traditional pink tinted tube repro-duction of older designs and the often clinical tightness that characterizes so many solid-state products. Tonally the ProLogue Premium Integrated tends to have a kind of light-footed character in the low frequencies. Bass is very well defi ned, and can supply enough pres-sure, but the real strength that char-acterizes the far more expensive tube amplifi ers with their larger output trans-formers, is missing a bit. Distortion lev-els are noticeably lower, and the tonality is far more natural with the new tube cir-cuit. An excellent fi rst impression!

Listening 2 - EL34 power tubes

The next listening session consisted of exchanging the KT88 power tubes for a quartet EL34 tubes. The EL34 tube is a very different power tube, so the pow-er goes down a bit from 2 x 40 Watts with the KT88s, to 2 x 35 watts with the EL34s; not a big deal. I continue for a while longer with the beautiful Janis Ian album and the track “What about love?” Like the rest of the album, this track

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grows beautifully during play. It starts subtly with acoustic guitar play, before adding a deep-reaching, growling elec-trical bass guitar and fi nally completed by the fragile voice of Janis and the high-energy of banging drums. The sonic dif-ference between both types of power tubes isn’t going to shock the world, but is still perceptible. The EL34 builds less on power and dynamics, and more on refi nement and spatial character. The beautiful studio-acoustics of Breaking Silence have been carefully fi ne-tuned blending “real” acoustical as well as arti-fi cial with an EMT tube echo plate. With

dio Team KT88 tubes from the Slovakian Republic. These EAT tubes are not only famous for their special qualities but also for their extreme price tag! A quartet of KT88 tubes costs a hefty 960, which is about half the retail price of a new ProLogue Premium Integrated Amplifi -er! I have heard a lot about these tubes, but never had the opportunity to listen to them myself. The EAT KT88s come very well packed in a beautiful printed carton box with precut foam and include a number of test certifi cates. Physical-ly they stand out from other KT88s be-cause of their satin black tube base; on most others you fi nd chrome. What makes these tubes so expensive is the labor-intensive manufacturing process, in combination with the traditional build processes and selected materials. For example, it takes six to eight hours per tube just to execute the vacuum proc-ess; this is three to four times longer than the competition. Also these tubes are burned in twice and used for 24 hours in an amplifi er for various test procedures, after which measurements are taken, providing the tube passes its screening process. Once I had removed the orig-inal Chinese tubes, I carefully inserted the EAT tubes into the snug PrimaLuna tube sockets. Next I eagerly switched

the EL34 tube, this recording breathes even more and now the amplifi er lets you hear an even more feminine Janis. The sound is also a bit sweeter, more subtle and spacious compared to the KT88s; the latter having a tighter and more impactful bass, better equipped to handle larger dynamic contrasts. In the end, your own tastes and the rest of your equipment will help to decide which tube you will prefer.

Listening 3 - EAT KT88 power tubes

For the last session we are fi nally going to use the extremely ambitious Euro Au-

NEXT

Associated Components:Loudspeakers Master Contemporary C, Verity Finn

CD-Player North Star Design T192 + Extremo DAC,

Accuphase DP600

Integrated amplifi er Unison Research Performance, Accuphase E-350

Equipment Racks Finite Elemente Pagode Master Reference HD12,

Furnaud Pressand 1ST

Interconnect Siltech Royal Signature Empress

Digital cable North Star Design White Gold I2S

Loudspeaker cables Nirvana SX, Siltech Classic Anniversary 770L

AC cables Nirvana PC, Kemp Reference,

Essential Audio Tools Current Conductor,

Siltech Royal Signature Ruby Hill II

Acoustic treatment RPG Modex Plate (4x),

Acustica Applicata DAAD 4 (2x)

57

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ed

the amplifi er on and after a short while (lucky me!) all 4 power tubes begin to show their warm glow. Since EAT burns in the tubes at the factory, there is no need to do that yourself; and with the superb Adaptive AutoBias circuit from PrimaLuna, it is possible to make a very fast judgement. The verdict? That isn’t too diffi cult to describe, as I am almost immediately overwhelmed by the enor-mous difference. No, I take it back; by the enormous improvement! Rarely have I ever, regardless of tube amp, heard such a big change and real improve-ment after exchanging a tube. Usually it is a little bit more of this, a little less of that, and if you are lucky you at best hear a subtle improvement. Make no mistake, the original PrimaLuna tubes are of the highest caliber, but after using the EAT tubes, the ProLogue Premium Integrat-ed Amplifi er soars to another level! The improvements came especially in areas where the differences with my own ref-erence tube amplifi er, the much more ex-pensive Unison Research Performance amplifi er, were the biggest. Right away I noticed a huge increase in dynamics and associated contrast, a lot more re-solving power, and the tonal balance is a lot more neutral and slightly less for-giving. Most of all, the EAT tubes give a feeling of 3-dimensionality, that feel-ing of listening to real artists instead of a reproduction. At fi rst thought, it might sound ridiculous to pay almost 1000 Euro for power tubes in an amplifi er that costs 2000 Euro, but on the other hand it proves just how much more quality is available in the PrimaLuna concept than I originally expected. The only disadvan-tage is that with frequent use, these EAT tubes have to be replaced after about 3 years; a fairly costly business.

Conclusion

With so many other infl uencing parame-ters, this review has become quite vast, serious and complex. I tried to discuss as many issues as possible, both inside outside, to be able to fully understand these remarkable products. To achieve this I received a lot of assistance from the PrimaLuna design team, and I am grateful for their help. If I were to de-

fi ne these new products in one word, that word would be easy. The reproduc-tion is very easy and relaxing, a result you can enjoy comfortably while reading a book, or while critically listening to a new piece of music you just bought. The functions are just as simple as a tran-sistor set, just switch them on and they play. Immediately the ProLogue Premi-um pieces sound just as they should. With respect to their predecessors, large steps ahead have been made. There is now a larger and more stunning chassis, better components throughout, and most important the dramatic sonic improvement in the preamp section. The differences between the mutually tested power tubes shows how well the basic qualities of these products actually are. The standard KT88s are nice all-round, fl uent and powerful. The EL34s are a bit shy and sweeter, but also more refi ned and spacious. The EAT KT88 tubes boost/catapult the amplifi er to a high-

er level. You must hear the improvement for yourself in order to believe it. Now I am left to ponder; how will the more expensive up-coming [EpiLogue] Pri-maLuna models sound with these EAT tubes? Enough for me to dream of. For-tunately the pleasant prices of these re-view products are not a dream, but pure reality. PrimaLuna strikes again!

Text & photography: Werner Ero

DUROB AUDIO B.V.TEL: [email protected]

PRICES:PRIMALUNA PROLOGUE PREMIUM INTEGRATED AMPLIFIER (EL34) € 1,900PRIMALUNA PROLOGUE PREMIUM INTEGRATED AMPLIFIER (KT88) € 2,150PRIMALUNA PROLOGUE PREMIUM CD PLAYER € 2,975

END

58

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DiaLogue One Reviews

POSITIVE FEEDBACK ONLINE - ISSUE 36

primalunaDiaLogue One integrated amplifier

as reviewed by Ed Kobesky

ED KOBESKY'S SYSTEM

LOUDSPEAKERSPSB Alpha T.

ELECTRONICSPrimaLuna ProLogue Two integrated amplifier, Rotel RQ-970 phono stage.

SOURCESRega Planar 3 turntable with Linn Basik LVV tonearm and Denon DL-110 cartridge, Rega Planet CD player, Sony DVP-NC875V DVD/SACD player, Pioneer DV-563A universal player.

CABLESMonsterCable Interlink 400, 250 and 200 interconnects, AudioQuest Alpha Snake interconnects, MonsterCable XP speaker wire, others.

ACCESSORIESRecord Doctor II record cleaning machine with Disc Doctor brushes, Sennheiser HD580 headphones, Rotel RLC-900 line conditioner.

Hard to believe, but nearly three years have passed since I last heard from Kevin Deal, the owner of California's Upscale Audio and the man behind PrimaLuna electronics in the USA. It was worth the wait. Last time, the west coast's preeminent tubemeister was rolling out his new line of high-value, integrated tube amplifiers. He sent me the ProLogue Two, a compact KT88-based unit that's built like a tank and performs with uncommon delicacy. I raved about it then and still feel it's one of the most sonically appealing integrated amplifiers for around $1500.

Since then, the PrimaLuna line has expanded to include separate preamplifiers and amplifiers (stereo and monoblock) in addition to a well-regarded, optional moving magnet phono card and even a CD player with tube-based clocking device. Kevin's no fool. Unlike many people in the audio industry, he's a smart businessman who does a great job at generating publicity. It would have been easy for him to send me subsequent PrimaLuna products knowing full well I'd probably rave about them, too. But he didn't.

So, when my caller ID did finally light up, I knew it would be about something special—and it was. The new DiaLogue series takes ProLogue performance to the next level with even better parts (if that's possible), more features and higher resolution. The DiaLogue One is EL-34 based while the DiaLogue Two uses KT-88 tubes. Kevin sent me the DiaLogue One and it's one hell of a looker, with a swooping steel and glass tube cage and multiple coats of hand-rubbed lacquer that achieves a flawless finish Porsche would be proud of. The stainless steel remote control feels like it will last a lifetime or two.

Like all PrimaLuna products, the DiaLogue One uses PrimaLuna's proprietary Adaptive AutoBias circuit that continually monitors and adjusts the bias. It works flawlessly and unobtrusively to the point where owning a PrimaLuna tube amplifier is little different than owning a solid-state amp. Every once in a while, the owner will need to replace a tube or two, which is about as difficult as changing an incandescent light bulb but probably less frequent. To maximize tube life even further, it also incorporates a "soft start" circuit to gently power up the amp and reduce thermal shock. Most of the interals are linked by point-to-point wiring, so aside from a few ICs (for the auto-bias and optional phono stage), there's little that might be prone to premature failure.

Unlike the ProLogue amps, however, the DiaLogue is switchable from triode to ultralinear mode at the touch a button on the remote control. For those who don't know (or, like me, hardly care), ultralinear operation basically forms a negative feedback loop around the output stage and allows for higher power output. Triode operation allows for a much smaller voltage swing. Consequently, output power is much lower.

If you're as baffled by basic electrical engineering as I am, just know this: in ultralinear mode, the Dialogue One outputs 36-watts and sounds more dynamic and fleshed out, while in triode mode, it musters 18-watts with a notably more transparent midrange at the expense of just about everything else. I'm not a triode guy, and I never will be. I think the totality of the musical presentation is important so I'm not willing to sacrifice general realism for ultra-realistic, über-present vocals. Then again, I also have nothing against crossovers and have little interest in the kind of full-range horns that triode folks tend to enjoy.

Here's another thing you should know: the DiaLogue One's relatively low power rating completely belies its ability to drive even finicky speakers. It barely broke a sweat with the inefficient Spendor S5e floorstander. Though quoted as an 8 ohm speaker with an 87dB efficiency rating, some testers have reported that it's more like 4 ohms and 83 dB. Even in triode mode, the DiaLogue Two powered the Spendors to real-world listening levels without notable strain—though the combination of British loudspeaker and triode mode was hardly a synergistic match. Of course, a true triode guy would never put those two together. Switching to ultralinear mode, the amp really took control of the Spendor drivers with tremendous authority and helped to deliver more definition and deeper bass than I'd experienced with significantly higher-powered solid state amps.

In fact, the DiaLogue One is a "best of both worlds" kind of product. It provides nearly all of the dynamic slam and frequency extension you'd expect from a solid state amp at this price, together with the liquidity of tubes. Come to think of it, that's exactly what I said about the ProLogue Two three years ago. There is definite design continuity here. Listening to both units back-to-back (using the same EL34 power tubes), the DiaLogue did what the ProLouge does—only better. So, at the risk of appearing unoriginal, I thought it best to go back to my review of the older product for a discussion of listening impressions. (Quotes from the ProLogue Two review are in italics.)

"The first thing I noticed was a unique sense of air and aliveness." Check. Listening to both units head-to-head with a pair of Triangle Celius-202 floorstanders, the DiaLogue One delivered precisely that, only more so. Everything seemed more real, more transparent. If the ProLogue Two is engaging, then the DiaLogue One is positively captivating. Some people might confuse its liquidity for tube-induced gloss, but listen closely with a revealing speaker like the Triangles. You'll find it's not the case.

"When the music started, the ProLogue Two surprised—no, shocked—me by painting a smooth sonic picture that was also controlled and coherent. Many tube amps I've heard are slow in the midrange, dull on top, and loosey-goosey on the bottom. Not the ProLogue Two. It can't compete with solid-state amps in terms of tightness and fastness, but it never sacrifices detail to provide a warm, soothing presentation." Check.The difference here is that the Dialogue One can compete with solid state amps in its ability to deliver deep, controlled bass and stop-on-a-dime transients. It's tight as a drum, and not "for a tube amp" but without qualification.

"I'd have no qualms about pairing it with sources and speakers that cost many times its absurdly low price." The DiaLogue Two may not be quite the screaming bargain its little brother is, but it is a tremendous value and I do not question for one second its potential to be the centerpiece of a system in the $20,000 range. Plain and simple, it's just that good. You'd be forgiven for thinking that no expense was spared in its design and manufacture. You can visit Upscale Audio's website for more information on the many ways in which it is (over)built. Or you can do what I did and simply lift it up. At nearly 65 pounds, it's a bruiser, even for a fit 33-year-old.

The DiaLogue One is built in China but, as brand owner Herman van den Dungen stressed in a recent interview, "it is not a Chinese amp." That is to say, it's a western design that meets European Union specs and happens to be built at a factory in China, where production is overseen personally by either Hermann himself or one of his team members. According to importer Kevin Deal, we're not talking about simple spot checks. "You cannot get a consistent, high-quality western product unless you have western people sitting on the factory hours a day," he said. "That's what it takes, so that's what they do."

For the record, I've had the ProLogue Two in use for three years and it has never been anything less than 100% reliable. I pay it no mind and it demands nothing in the way of special attention. I see no reason to expect less from the DiaLogue series. That's why I would strongly recommend the DiaLogue One for those who, by necessity, have combined their two-channel and home theater systems. It features a nifty home theater pass-through that completely bypasses the preamp section. You can keep your receiver and enjoy tube sound—without the hassle of tubes.

I guess I'm obligated to mention that the original ProLogue One is nearly $925 less expensive than the $2295 DiaLogue One. They sound very similar so, if you like what you hear and can live without a remote control and home theater pass-through, then you can get much of the DiaLogue's performance for less. However, this is also one of those cases where you really do get your extra $925 worth—and then some, and then some more. The DiaLogue One is a significantly more lifelike amplifier that, despite a similar power rating, maintains a much more confident grip on speakers. I never thought I'd run across an affordable tube amp that could make the same magic with fast, efficient speakers like Traingle and taut, inefficient speakers like Spendor, yet here it is. How cool.

I closed my review of the ProLogue Two by saying that "music flows through it gracefully. What comes out is lush but not slushy, alive but not prickly, and involving as all get out. The PrimaLuna ProLogue Two garners my strongest recommendation. It's not merely a great tube amp, but a great amp, period." Ditto for the PrimaLuna DiaLogue One. It's a wonderful, luxurious-sounding amplifier that I'm wildly enthusiastic about. I'll spare you the usual audiophile jargon and close by simply saying that the DiaLogue One sounds about as close to live music as you're going to get at this price, especially if you value warm-blooded, breath-of-life realism. EdKobesky

DiaLogue One integrated Retail: $2299

PrimLunaweb address: www.primaluna-usa.com

Upscale Audio web address: www.upscaleaudio.com

DiaLogue Two Reviews

With its ProLogue series of tube electronics, PrimaLuna burst onto the audio scene a few years ago and established itself as a serious contender in the value-priced sweepstakes. Designed in the Netherlands, built to high production standards in China, and discributed in the U.S. by tube maven Kevin Deal, PrimaLuna’s fi rst offerings, the ProLogue One and Two integrated amplifi ers, were followed by a separate preamplifi er, stereo amplifi ers, and monoblocks. I lived happily with ProLogue Six amplifi ers during an extended review period and was impressed by their natural and engaging sound, and the quality of their point-to-point wiring and parts. PrimaLuna’s Adaptive Auto-Biasing and soft-start features combine to help make owning an audio component with glowing devices musically satisfying and “easy as pie” to operate and maintain.

PrimaLuna DiaLogue Two Integrated Amplifi erJim Hannon Photography by Adam Voorhes

Outside the midrange, the gap between these two units widened, with the DiaLogue offering superior transparency, midbass weight and articulation, extension at the frequency extremes, and micro- and macro-dynamic swings. For example, the tympani rolls on the Liszt were more explosive with the DiaLogue, and the ensem-ble on Electric [Chesky] seemed to play with more rhythmic drive, aided by the enhanced solidity and atticulation of Victor Bailey’s electric bass and high-frequency shimmer and decay of Lenny White’s cymbals. With the DiaLogue, perform-ances were more thrilling and 3-D, with clearer ambient cues, instruments like the cello on Haydn’s Cello Concertos [Pierre Verany] had better timbre, with more body and fl eshed out overtones. If you own a speaker that’s more diffi cult to drive, the DiaLogue is the clear choice. Whereas the ProLogue Two strug-gled mightily to drive the Quad ESL-2805 loudspeakers, distorting dynamic peaks with either the 4- or 8-ohm taps, the DiaLogue

drove the new Quads “effortlessly” and was able to extract more bass extension and weight than I could have imagined, without any bloat or muddiness. I also preferred it sonically to thc more powerful ProLogue Six monoblocks, which had just departed from my listening room prior to the DiaLogue’s arrival. Besides its superior bass performance, the DiaLogue out-pointed the Sixes in terms of fi ne-detail retrieval, upper-midrange purity, and high-frequency openness and extension. The DiaLogue Two’s ability to faithfully reproduce the realism of the piano was shocking. One literally hears the funda-mentals and overtones resonating from the piano’s sounboard. I was amazed at its bass punch and foundation on Alain Planes’ re-cording of the Debussy Preludes [Harmonia Mundi], its explosive dynamics on Vladimir Ashkenazy’s recordings of Beethoven’s last piano sonatas Nos. 28-32 [London], and the subtle details and nuances that emerged from Ignace Paderewski Plays Beethoven, Liszt, Schubert, Debussy [Klavier]. While Paderewski reportedly hypnotized audiences in live performances, I sat there transfi xed listening to his admittedly romantic, but oh-so-wonderful inter-pretations through the spectacular DiaLogue/ESL-2805 combo. At the push of a button on the remote, I switched the Dia-Logue Two from ultralinear to triode operation instantaneously. Adjusting for level (the output is halved in triode), the sound be-came a bit warmer with more image depth, at theexpense of a slight increase in noise level and some softening of the bass and highs. Massed strings were slight-ly lusher, with a lighter, “feathery” quality.

At the 2006 Winter CES, Kevin proudly pointed to a proto-type of an integrated amplifi er from PrimaLuna’s new, upscale Dia-Logue series that was on silent display. The fi rst thing he said to me was, “Lift it up!” I did, but I should have put more of my legs into it. This baby was almost double the weight of one of the ProLogue integrated units. Given my very positive experience living with the PrimaLuna monoblocks, I was anxious to audition this new inte-grated amplifi er and see how it compared with its ProLogue Series counterpart. My accommodating local dealer, Brian Hartsell at The Analog Room, kindly loaned me a DiaLogue Two and a ProLogue Two integrated amplifi er so I could do the comparison. The KT88-equipped DiaLogue and ProLogue Two units sport many of the same premium parts, have similar power ratings (when the DiaLogue is in ultralinear mode), and include those won-derful auto-biasing and soft-start features. Consequently, it’s not sur-prising that they also share several sonic qualities, too, when driving speakers with relatively benign loads. Both have an engaging and highly musical midrange, and their sonic differences in the midband are subtle. As was the case with the ProLogue Six monoblocks, both of these PrimaLuna integrateds get the sound of massed strings and voices right, a failing of far too many high-defi nition components. They add no additional edge or stridency yet still maintain very good clarity atId detail on recordings like Beethoven’s Sixth Sym-phony (Kubelick on EMI), and Liszt’s Dante Symphony [Telarc]. Strings on the DiaLogue had a bit more realistic bite and presence, but not brightness, resulting in a more exciting perfollnance. Sarah Vaughn’s voice on Ballades [Roulette Jazz,] was a tad purer with the DiaLogue, and her voice had more intensity.

However, one’s preference for either triode or ultralinear mode will likely depend on the speakers used, the type and brand of output tubes, and even one’s mood. For example, if I wanted more impact, I switched to ulrralinear, but for more agressive recordings, I moved back to triode. On my original Quads, I preferred thc more relaxed triode mode, but on the new Quad ESL-2805s and Hyperions, I found myself typically listening in ultralinear mode, with its more extended, dynamic, balanced, and thrilling presentation. Since the linestage of the DiaLogue can be completely by-passed, I also used my reference preamplifi er with the DiaLogue Two, and the soundstage was literally wall-to-wall on great analog recordings. String tone was gorgeous, and tnunpets had the requisite “ping” on Holst’s A Fugal Overture [Lyrita], suggesting that the perfonnance of the amplifi er section of the DiaLogue is very fi ne, indeed. Using only the MFA’s phonostage with the DiaLogue, string tone remained beautiful and the soundstage was still suprisingly ex-pansive, but the image did not extend outside the boundaries of the speakers. Nevertheless, this level of performance through a mod-estly priced integrated amplifi er is quite stunning. Despite its outstanding performance, the DiaLogue Two has some limitations. While it has more dynamic explosiveness and midbass weight than any 38watt integrated amplifi er I have ever heard, you might need to look elsewhere if you have power-hungry speakers. But don’t be surprised if the DiaLogue’s output is all you need. Some may prefer the immediacy and purity of the best SET amplifi ers made, and offers many other compensating virtues. If you need more luslmess, try a set of EL34 output tubes, but the stock Genelex KT88 knock-offs sounded lush enough to me and have a tad more power, bass authority, detail, and high-frequency extension. Lastly, a PhonoLogue moving-magnet phonostage can be added internally to the DiaLogue, but it is limited to moving-magnet or high-output moving-eoil cartridges. While its perfonnance rivals separate phonostages around $500, and is defi nitely a good value, I’m hoping that PrimaLuna will introduce a companion DiaLogue phono card, or external module, that’s even better. Great wide-bandwidth transformers, a hefty damped chas-sis, an intuitive remote control with triode switching, and an effec-tive direct-bypass capability combine to raise this PrimaLuna’s per-formance at least another level (or ‘Two”) above the the ProLogue Series. If the DiaLogue Two is representative of forthcoming units in PrimaLuna’s new, higher-performance line, audiophiles and mu-sic lovers who are value- and performance conscious, and want tube electronics that anyone can operate and maintain are in for a treat. The DiaLogue Two is a keeper.

Several well-executed design elements combine to signifi -cantly improve the performance of the DiaLogue Two over its ProLogue Two counterpart. The most obvious are the unit’s signifi cantly increased chassis weight and improved cosmetics. However, the most important of these are the Dialogue’s “beefy” wide-bandwidth output transformers. Just because an amplifi er’s transformers are more massive doesn’t mean it will actually sound better overall. This is a tricky business, and there are too many cases where a com-pany’s amplifi ers with smaller output transformers sound better in the midrange and highs than those with larger ones. Typically, a larger transformer will yield better bass drive and control, but can actually degrade the quality of the midrange and highs. To reap the sonic benefi ts of these heftier transformers across the entire frequency spectrum, Primaluna used a labor-intensive “halfspeed-winding”

technique. According to PrimaLuna’s Herman van den Dungen, during the DiaLogue’s design phase, the resistance of the transformers was measured after each coil winding. Many versions, with different coil windings were evaluated sonically until the one with the best combination of low dis-tortion and the right balance was identifi ed. Ranges of dif-ferent isolation materials and types and thicknesses of ironwere also evaluated to reduce distortion. Tighter toleranceparts were used in the DiaLogue as well as PrimaLuna’s proprietary Adaptive AutoBias circuit reported to reduce tube distortion by 40% to 50%. The result is an integrated amplifi er with incredible bass slam for its output rating, a seductive midrange, and extended “fatigue free” highs. It appears that a lot of thinking went into the design of the remote control, too. The unit fi ts easily and fi rmly into your hand and the volume can be controlled by your thumb. The button to switch from ultralinear to triode mode is at the top of the remote, so it takes a deliberate action to

change modes.A red light, easily

seen on the top ofthe Dialogue, indicatesultralinear mode and a

green light indicates triode.Switching is instantaneous, but

beware. When listening in triode mode, you can easily increase the gain only to be jolted by an increase in volume when you switch back to ultra-linear. As a precaution, I found myself reducing gain a bit in triode prior to moving to ultralinear. The Dialogue Two has a true home-theater “bypass” feature, enabling its amplifi er section to be controlled by an AVR, preamplifi er, or linestage. It removes the Dialogue’s linestage and its volume control completely from the signal path, so don’t try plugging your CD player directly into these inputs unless you want to fry your speakers. What’s great about the bypass feature is that if you’ve already invested in a highperformance preamplifi er or linestage, you can still use it with the Dialogue. Moreover, the Dialogue can easily inte-grate into a home-theater system merely by connecting the left and right preamp outputs on the AVR to the HT inputs on the Dialogue. JH

SPECS & PRICINGPRIMAlUNA DIALOGUE TWO INTEGRATED AMPliFIERPower output: 38Wpc (ultralinear); 21 Wpc (triode)Frequency Response: 10Hz - 30kHz (±ldB)Inputs: Five pairs stereo RCA, one pair home theaterOutputs: One pair stereo RCATube Complement: Two 12AX7s, two 12AU7s, four KT88Input Impedance: 100kOhmDimensions: 15.9” x 15.2” x 8.3”Weight: 63.8Ibs. (70.5 Ibs. shipping weight)Warranty: Two year limited (six-months on stock vacuum tubes)Price: $2625 ($2804 as tested, with PhonoLogue MM phonostage)

UPSCALE AUDIO2504 Spring TerraceUpland. CA 91784(909) 931-9686www.upscaleaudio.com

ASSOCIATED EQUIPMENTSME 20/12 turntable system with Sumiko Celebration car-tridge; VPI Aries turntable (TNT V platter & bearing), Gra-ham 1.5 arm (w/2.2 bearing), and Koetsu Black cartridge; Pro-Jed RM-S and Debut III turntables; MFA Venusian pre-amplifi er (Frankland modifi ed); Primaluna Prologue Six and Quicksilver 8417 monoblock amplifi ers; Precision Fidelity M-7A power amplifi er (modifi ed); Hyperion HP5-938. Quad E5L2805 and E5L-57 (PK modifi ed) loudspeakers; Virtual Dy-namics and Goertz cables, etc.

AssociatedEquipment:

AnalogFront EndAnalog Front End Michell Orbe SE II turntableWilson Benesch Act 0.5 tone arm Benz-Micro Ebony L Luxman P-405 turntable Audio-Technica PB12S cartridge

Digital Front EndCAL Icon MkII (as transport)Bolder Cable modified ART DI/O processor

AmplificationMusical Surroundings Nova Phonomena Parasound P/LD 2000 line stage Antique Sound Lab AQ1003 DT Kavent A210 hybrid integrated amplifier NuForce Reference 9V2 SE

LoudspeakersSilverline Prelude II

Cabling

PrimaLuna DiaLogue Two Integrated Tube AmplifierA Strong Case for Tubes

June 2008

Okay, I admit it—I read Jim Hannon’s review of the PrimaLuna DiaLogue Two integrated tube amplifier in the October 2007 issue of The Absolute Sound magazine. And although I don’t lend automatic credence to any review I see in print, the review did get me interested enough to request a review sample and to see for myself whether or not all the PrimaLuna hype is justified.

Make no mistake; the DiaLogue Two is a thoroughly modern amplifier that includes a very hefty anodized aluminum remote control. It was designed in the Netherlands by Herman van den Dungen and is manufactured to stringent standards in China.

Sonoran digital coax Audio Metallurgy GA-0 InterconnectsAudio Metallurgy Gold Reference speaker cables SignalCable Silver Resolution and Analog Two interconnects SignalCable Silver Resolution speaker cablesSpeltz Anti-Cable speaker cables (Silverline’s bass section) SignalCable MagicPower AC and Digital AC cords

AC ConditionersMonarchy AC-regenerator PS Audio Duet and UPC 200 AC filters EFI Electronics AC-power filter

AccessoriesPlateau equipment rack Black Diamond Racing Source Shelf Andy Bartha Audio WhatchamacallitsBlack Diamond Racing #4 cones VanEvers wood-block kit Shakti Stones Blue Circle Cable Pillows Helmholtz resonators (homemade)Michael Green Room TuneSonex panels

What we have here folks, is a 38-watt per channel integrated tube amplifier, that uses two Chinese KT88 per channel (patterned after the British Genalex KT88s) to develop its rated power into 8 ohms. One can switch from the 38-watt ultralinear mode via a push of the button on the remote, which cuts power down to 21 watts per channel triode. The input section uses two 12AX7 and two 12AU7 tubes.

From the get-go it was apparent that this was a very solid and well-built amplifier. Weighing in at a robust 64 pounds, with its oversized power and output transformers and thick aluminum faceplate, it certainly makes an impression the first time you have to lift it and carry it up a flight of stairs.

The heavy-gauge polished steel chassis is coated in a 5-step process with an automobile-grade dark blue paint. High quality parts are used throughout from the extra large half-speed wound output transformers to the ceramic tube sockets, Alps potentiometer, Nichicon and Solen capacitors, and WBT-style speaker terminals. Gold plated input jacks.

The DiaLogue Two is hand-made and point to point wired although it does contain a couple of internal printed circuit boards, one notably for the unique “Adaptive AutoBias” circuit, which is claimed to optimize valve performance and reduce distortion by 40 to 50%. It also extends tube life and makes the unit more reliable and user-friendly.

Here’s the cool thing about the Adaptive AutoBias – almost any output tube can be plugged in and played. This unique biasing circuit will sense the tube type and automatically set the bias for optimal operation. You don’t need to do anything other than install your favorite tubes, then sit back and enjoy! In addition to KT88s, the amp can use 6550, KT90, EL-34, KT77, 6CA7, 6L6GC, KT66, 7581, and 6V6GT tubes, or any of their

equivalents. Talk about a tube-roller’s paradise!

Features:The DiaLogue Two has a rotary volume control and six switched inputs, which include a HT input that bypasses the volume control and the tube input section. Therefore, when using the HT input, the source must have its own volume control if you don’t intend the DiaLogue Two to play into your speakers and ears at FULL VOLUME!

One very nice extra cost option is the installation of a very articulate and musical MM phono stage (more on this later). The $199 extra was installed on my review sample on AUX 2. The rocker off/on switch is on the front left side of the chassis and is not controlled by the remote control.

The rear panel contains 6 pairs of gold-plated RCA inputs and one pair of RCA tape outputs plus a grounding post. There are WBT style speaker posts for 4 or 8 ohms, and an IEC AC receptacle to facilitate after-market power cords (I found the stock cord to sound very respectable). The DiaLogue Two contains internal AC and plate fuses, and a few spare fuses are included in the package, as are a pair of white handling gloves.

The remote is an attractive black-anodized heavy-metal unit that is quite useful. In addition to the usual volume control, you can choose inputs, mute and un-mute, and switch from ultralinear to triode operation at the push of a button. It appears to have other transport control buttons that will conveniently operate the PrimaLuna CD player. The remote has rubber rings installed at each end so that it won’tscratch your furniture. Nice touch.

I did some experimenting with the ultralinear to triode switching and found the triode mode to be generally a bit warmer and slightly sweeter sounding. It seemed to work well for low level listening and for acoustic singer/songwriter music. The ultralinear mode was used for most of my evaluation because it provides greater power and better articulation at the frequency extremes.

Notes on Impedance and Tube-Rolling:The first thing one needs to determine when installing the DiaLogue Two in a system, is whether to use the 4-ohm or 8-ohm speaker posts. This would seem perfectly straight forward, but in my experience it was not exactly the case.

Since my Silverline Prelude speakers have a nominal 8-ohm rating, I started with the 8-ohm taps. In that configuration, the DiaLogue Two sounded very matter-of-fact and very similar to many solid-state amplifiers. The sound was clean and extended at the frequency extremes, but the harmonic sweetness I had expected to hear from the DiaLogue Two was somehow missing in action.

Changing my speaker wire to the 4-ohm terminals allowed the amplifier to sound sweeter and much more like a very good tube amplifier. So, since my 8-ohm Preludes seemed to prefer the 4-ohm setting (I know I did!) I used the 4-ohm taps for the remainder of my evaluation. My advice is not to assume anything and to try both impedance settings to determine which sounds best to you.

The Chinese KT-88 Genalex knock-offs performed very well in my system. The midrange was a bit forward, but the bass extension and articulation was quite healthy and the high frequencies were airy, non-fatiguing, and extended, without any obvious roll off. What I’m saying is that the stock KT-88s provide very respectable performance in the DiaLogue Two, which will satisfy many. Buyers should not feel that they need to run right out and buy some expensive NOS tube set.

But since I simply had to try out that Adaptive AutoBias circuit, I pulled a quad of JJ EL34 tubes from my Antique Sound Lab AQ1003 DT (ASL) amp and plugged them into the DiaLogue Two.

I powered up the DiaLogue Two with the EL34s and began listening. Now this was truly a sweet sound. The JJ EL34s sounded both sweet and natural in the ASL amp, and also gave a nice sense of depth projection. The highs were natural and extended, though not as extended as the new KT88s, but nonetheless, they provided quite a bit of detail and shimmer on cymbals and other high-frequency instruments. The midrange was, in a word, “gorgeous,” and in my room, the EL34s provided bass that was fairly equal to that of the KT88s, and perhaps it was even a bit more articulate.

Moving on to a quad of vintage Genalex KT66 gray-plate tubes, the sound became very detailed, but also very forward, and lost a bit of bass extension and punch. This was my least favorite tube match for this particular system.

So it is true that you can plug virtually any type of output tube into the DiaLogue Two and it will play just fine. It is also true (as with all tube amps) that each different tube type will have its own distinct character. Which one will sound the best to you will depend on your associated gear and your listening biases.

As for me, I was very impressed with the overall sound of the EL34 tubes in my system and consequently went on to use that tube set for the rest of my evaluation. They provided a bit more harmonic richness than the KT88s in the crucial midrange, and were just a touch more laid-back sounding.

Let the Games BeginI began listening to the DiaLogue Two with some familiar CDs. I was quite impressed with the amplifier, which offered more bass extension and punch and certainly more extended high frequencies than my ASL tube amplifier. But what impressed me the most about the DiaLogue Two was its near solid-state control of the bass combined with an uncanny ability to reproduce midrange notes, such as guitar chords, with a bit more power and dynamic flair than I had experienced with most other amplifiers. It quickly became apparent that this was going to be a thoroughly enjoyable evaluation. Indeed, the DiaLogue Two sounds more dynamic and actually has better bass control than some solid-state amplifiers I’ve had in my system

A Shocking Revelation!PrimaLuna’s USA Distributor Kevin Deal offered to install the optional phono board in my DiaLogue Two, and being an analogue man from way back, how could I refuse? The MM Phono was installed on the AUX2 input, which was as good a choice as any.

Kevin had enticed me by telling me that this phono board, which is made in Holland, works particularly well in the DiaLogue Two. It boasts a very high-quality op-amp, minimelf resistors, and a very short signal path. Although it is a solid-state circuit, my personal philosophy supports this approach (solid-state phono into a tube line stage). In my view, it keeps noise levels very low and provides better detail and articulation in the high and low frequency registers.

I cued up a Laura Brannigan’s Brannigan 2 LP (Atlantic 7 80052-1) and was flabbergasted when the needle hit the record and began playing “Solitaire.” I must say that Laura’s vocal and the backing instruments sounded jaw-droppingly musical and natural through the DiaLogue Two’s phono section. And when we got to “Squeezebox,”and the “squeezebox” made its entrance, the reproduction was smoother and more holographic than it had any right to be. With respect to the critical midrange reproduction, the DiaLogue Two phono was strutting its stuff big time. Even the lows and highs were as good as I’d ever heard them with this particular cartridge (though the midrange is its strength).

A few days later, I bought a used Luxman P-405 automatic belt-drive turntable from Craig’s List, and installed my mighty vintage Audio-Technica PB-12S cartridge with its Shibata stylus. As I recall, it received a good write up from TAS back in the day.

This time, I had my music-friend Mike and his lovely wife Kyle over to check out the system. Mike had brought some premium quality MFSL records and we played Boston’soriginal LP as well as one by Stevie Nicks. To me, the sound was decent, maybe a touch on the bright side, but really nothing too special.

So I said to Mike and Kyle, “How about if I put something on that’ll rip your heads off?”They looked at each other suspiciously, and then turned and said, “Uh, okay.” “Sweet,”said I.

I then dove into my 80’s 12-inch-single dance music collection and pulled out Jody Watley’s Real Love (MCA 23928). I cranked the volume a bit and then pressed the Start button on the Luxman. The song began with Jody talking, then some loud cymbals after which the bombastic bass line kicked in. I looked at Mike and he said, “I think the bass may be overloading the room a little.” I considered his veiled request for a volume reduction momentarily, then retorted, “That’s right bitch—Take that!” “Oh-Oh-Aaaah,”Watley wailed! It really was surprising how LOUD the DiaLogue Two could play the Preludes in my 11’x14’ room. And not only was the sound loud, it was clean and controlled.

My point is that the DiaLogue Two’s phono is a surprisingly great sounding addition. It provides a wealth of detail, impressive dynamic contrasts, and a wonderfully musical and dimensional midrange. I would expect it to equal or surpass outboard units up to $1000.

The real truth (if I must tell it) is that the seductive sound of the PrimaLuna’s phono stage had me checking and double-checking all the settings and adjustments on my much more expensive Nova Phonomena and Michell Orbe. I mean hell; the Orbe had to sound better than the Sony or the Luxman, right? And it did—after resetting the VTA, the tracking force, and the loading value.

Once I had recalibrated the Orbe, it sounded truly inspirational. Playing Stravinsky’s L’Histoire du Soldat, performed by the Columbia Symphony Orchestra from Stravinsky Conducts, 1961 (Columbia MS 6272) the coronet and the trombone had a richness and texture that I’ve rarely experienced. And the tympani, cymbals, and other drums sounded very poignant and convincing. I could easily hear the tuning of the skins on the various drums. In one movement there is a drum roll that just comes out of nowhere and is shocking in its level of transparency.

When I put the record back, I noticed that I had an Everest-labeled copy of the same piece (Everest SDBR - 3017) performed by the London Symphony Orchestra. The Everest recordings are renowned for being among the world’s best. This particular recording was mastered at the Belock Recording Studio using Ampex 300 stereo tape machines recording on half-inch tape via microphones from AGK, Telefunken, and Neumann.

I played the same movements of L’ Histoire that I had just listened to on the other recording and it was very evident that as good as the first recording was, the Everest recording was a considerable step up. The brass, woodwinds, and violins were so

immediate and detailed, and the drums so palpable that I had to suspend disbelief in order to believe that I was not witnessing the actual concert. In truth, the quality of the reproduction was about as good as it gets.

I realize that I was listening to two different orchestras recorded in two different venues, but still, the difference in recording quality was unmistakable. It seemed that the Everest recording likely used a different microphone configuration with better quality microphones, resulting in more apparent detail and intimacy.

CaveatsThe DiaLogue Two is a very hard product to fault, but I wouldn’t be a reviewer if I couldn’t find some small things to complain about, so here goes.

First, I would prefer to have a pair of volume-controlled preamp outputs instead of the fixed-volume tape outputs.

Second, I wish that the source selector defaulted to the last selected source at turn-on instead of automatically reverting back to the CD input.

Although the tube cage is uniquely styled, modern, and very functional, it’s just not my idea of eye-candy. Luckily it pulls up and off quite easily.

SummaryMy hat is off to the folks at PrimaLuna. What impresses me most about the DiaLogue Two amplifier is how well though out and executed this product truly is. It seems that the designer left no stone unturned when it came to considering what modern users would desire and look for in a tube integrated. From the Adaptive AutoBias circuit, to the verily useful remote control with on-the-fly UL/triode switching; then last, but far from least, the provision for an excellent low-cost onboard MM phono stage, the DiaLogue Two is a bona fide home run all the way.

As if all of the above are insufficient reasons to make a semi-expensive purchase, the clincher is the gorgeous musical presentation that this amplifier provides all day long. Its dynamic contrasts are among the best I’ve encountered; and although its midrange is beauteous, its superb articulation and command of the frequency extremes is what puts it ahead of the competition. Accordingly, I’ve committed to purchase the PrimaLuna Dialogue Two. I will surely enjoy it as my prime tube reference amplifier.

SpecificationsOutput: 38 watts x 2 ultralinear, 21 watts x 2 triodeFreq. Response: 10Hz-30kHz +/- .5dB THD: Less than 1% at full power S/N Ratio: 89dB Input Sensitivity: 270mV Power Consumption : 250 watts Dimensions: 15.2" x 8.3 " x 16 " (WxHxD) Weight: 63.8 lbs Inputs: 5 pair RCA / 1 pair HT bypassOutputs: 4 & 8 Ohm speaker taps / 1 pair RCA fixed tape outputTube Compliment: 2 - 12AX7, 2 - 12AU7, 4 - KT88 Price: $2,625 USD; Phono adds $199

DiaLogue Three & Seven Reviews

C M I C H E L B É R A R D

Certain readers may remember my review of the PrologueOne integrated amplifier. My time spent with this unit wasa humbling experience; its performance-to-cost ratio farexceeding anything I have ever tested as an audio reviewer.And now Prima Luna has done it again with the DialogueThree preamplifier and Dialogue Seven power amplifier.

Generally when I start a review, I search to see what hasalready been written about the equipment, to get a sense ofwhat I’m dealing with. In this case, all listening was donewithout having read any other reviews. My impressions arethus devoid of any outside influence apart from the experien-ce of the Prologue One.

TECHNICALDIALOGUE SEVEN MONO AMPLIFIERSThe amplifier offers two modes of power output: 70 wattsper channel in ultra-linear mode or 40 watts in triodemode. Frequency response is specified from 10 Hz to 100kHz. The unit has a single RCA input, impedance 100kOhm. On the output side, speakers can be connected to 2,4 or 8 ohm terminals. The amplifier uses two 12AX7 tubes,two 12AU7 tubes and four KT88 tubes. And pay attentionto your back, each unit weighs 63.8 kg pounds (29 kilos).External dimensions are 15.9’’ x 15.2’’ x 8.3’’ (40,5 x 38.5 x22 cm).

DIALOGUE THREE PREAMPLIFIERThe preamplifier is equipped with six stereo inputs, a loopfor a home theatre processor, a pair of tape outputs andtwo RCA outputs. Four 12UA7 tubes and two 5AR4 tubesprovide a gain of 12 dB. Of identical dimensions to theamplifier, and weighing 48.5 lbs (22 kg) the pre-amp ishefty. Frequency response is specified from 10 Hz to 30kHz. The unit is shipped with a very well-designed remo-te control of impeccable craftsmanship.

SET-UPSince these devices are capable of very high resolution, Ichose Actinote cables for the mains and interconnect. Iplaced the pre-amplifier on a thin Symposium platformand the amplifiers on separate stands. Being brand new, Ileft the equipment on and running for a few days beforemoving on to serious listening.

LISTENING“Blown away”, as they would say in the US. From the firsttrack, the Prima Lunas were a revelation. My system hasnever delivered so much music. All the music. Its what I’vebeen seeking for so long. Gone are the frustrations andshortcomings. Do you often listen to a record and feel ins-tinctively that the information is there, but it is not rea-

Prima Luna Dialogue Three PreamplifierPrima Luna Dialogue Seven AmplifiersPure nirvana

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ching you? That the bass is not all there, that there areholes, imbalances, that space and depth should be larger,musical timbres more accurate!

Once again, Prima Luna has capsized my boat. I comple-tely forgot technique and just listened to music. Fromrecord to record, I discovered everything I had missed forso many years. For the first time, I did not feel the need toadjust or improve anything. The sense of balance - though

I dare not say perfect, because there is always room forimprovement - in this case is hard to beat, within the limitsof my speakers and my listening room anyway.

It was the second time that my Verity Parsifals have deli-vered their full potential and their wonderful qualities. Noamplification system tested at home apart from theAudiomat Recital has been able to make them sing with asmuch ease and naturalness. They are power-hungry, but theDialogue Sevens have watts to spare and never ran outbreath during the listening sessions.

The problem of the Prima Lunas is that they have theability to nail you to your listening seat, not for hours butfor days. For the first week I didn’t even take notes, I wasso captivated by the music. I went through all my favouri-te records one after the other and the Prima Lunas neveronce let me down. They seemed almost to challenge me,saying, “Come on, try again!” with their cool and relaxedair, almost arrogant!

ON THE MENUBut I should explain my story a little more fully. I startedthe listening sessions with the Codex # 4 by Santiago deMurcia, performed by the Kapsberger Ensemble (AuvidisNaïve E 8661). Generally it is a murky, dense work, butwith the Prima Luna, the multiple layers of bass are clear,precisely drawn with no overlap. One can clearly distin-guish each instrument’s place in space. And add to thatthe veracity of the instrumental timbre. The triangle, thestrings, the percussion: natural. The image is sharp in allthree dimensions. Transients are completely maintained.

For those who know me, no listening session is comple-te without Les Sept Paroles du Christ by Theodore Dubois

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(Fidelio FACD008). With the substantial power of theDialogue, I wondered if they would not exaggerate thesub-bass. I needn’t have worried. The Dialogues just didwhat they had to do: reproduce clearly and with authori-ty, but without exaggeration. I was relieved. Still scepti-cal, I pulled out Cape Town Revisited, a live recording ofthe Abullah Ibrahim Trio made at the Spier Estate, CapeTown, South Africa December 13, 1993 (Justin Time JTR8483-2). The drum is closely-miked and this will oftenlead to the bass drum sounding fuzzy and exaggerated,encroaching on the rest of the instruments. Not in thiscase. The Dialogue is extremely fast and leaves no roomfor softness. But the best part is the real sense of beingat the show. You close your eyes and, as I mentioned inanother article, you wait for the bartender to come andserve you.

This test being successful, we move on to massedorchestras. Mahler’s third symphony performed by theChicago Symphony Orchestra (CSO Resound). One thing tonote, at the beginning the timpani can be heard veryfaintly at the back of the orchestra. Almost imperceptible.

Before the Dialogue we guessed at their presence. Withthe Prologue One integrated, we can start to sense it andwith the Dialogue, there is no need to guess. Even verylow you can hear them very clearly.

When the orchestra plays to its full extent, the musicgrips the road with ease. Everything is open. The differentlayers of sound are sharp, defined. We can easily “see” thesuccessive rows of the orchestra. The sound-stage extendsfar beyond the width of the speakers.

Turning now to the piano with Études Symphoniquesop.13 by Robert Schumann, performed by Mikhail Pletnev.Already repeatedly impressed by this recording, the PrimaLuna would raise it yet another notch in its realism. Theamplifiers add body and presence, the piano as if it is inthe living room. I know it sounds corny, but this is so truethat it is quite disconcerting. This led me to a session of

vinyl-spinning with The Michel Petrucianni Trio: Pianism.The track “The Prayer”: total happiness. Always the sameimpressive sense of presence, the force of the piano final-ly materialized in the room. Then came Tracy Chapman’sFast Car. The beauty of the deep bass on offer furtherincreased my admiration of the Prima Lunas.

A key characteristic of the Dialogue Sevens is theirextreme power coupled with speed and control; the onlyones I have heard in my system that combine these threeattributes. Many electronics have the power, but not thecontrol, providing deep bass, but without definition,while others offer definition without power.

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From the first track, the Prima Lunas werea revelation. My system has never delive-

red so much music. All the music. Itswhat I’ve been seeking for so long.

Like many of you, I have often been frustrated to hearso much more detail, space and well-defined bass whenlistening through headphones, as compared to listeningthrough loudspeakers. This is particularly true for TheGarden by Andreas Vollenweider. For me, the Prima Lunassolve this frustration once and for all with even more pre-sence and naturalness, allowing the music to connect at avisceral level and not just with the head.

Moving on to more subtlety. Scott Ross on the harpsi-chord. Rameau. Every note is clear, surrounded by its haloof light. The harpsichord has body, weight and resonates.One feels it physically present, not just a series of ethe-real notes.

The other outstanding quality of the Prima Lunas istheir ability to preserve the realism and beauty of recor-dings. They have all the advantages of tube amplificationwithout the sonic compromises.

“But wait, there’s more: Buy a Dialogue Seven amplifiersystem and receive a second one free!” Two amplifiers forthe price of one? Absolutely, as you have the choice ofultralinear or triode mode. Triode mode is generallyrecommended for small string ensembles or chambermusic, for example. But I concur with other colleaguesthat this is not a hard and fast rule. It depends on yourtastes and on the recordings. This possibility definitelyallows you to fit the mode to the music in many cases. Intriode mode the power is reduced but delicacy and detailare improved. It also depends on the speakers used. Toswitch from one mode to another, simply press the buttonon the remote and voila. You can do this while listening,so the comparison is instantaneous. On the maintenanceside, no worries. With its automatic self-bias system, noadjustment is required. The listener can concentrate onthe music without worrying about the technology.

CONCLUSIONAnd the price. Four times less expensive than one mightthink, without any compromise. The value of Prima Lunaequipment is in my opinion difficult to match. I know ofno other device on the audio market that offers so muchfor such a reasonable price.

I had great difficulty writing about the Prima Lunas. Ijust wanted to listen. In my system and my listeningroom, it is the amplifier that has brought me closest tothe original musical performance. It offers everything:power, control, truthfulness, timbral accuracy, space andemotion. It simply disappears, leaving you with puremusic.

Translated by Jan-Erik Nordoen, reviewer for Son & ImageMagazine.

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Distributor : AudioScape Canada Inc1-888-919-0707www.audioscapecanada.ca

DiaLogue Six Reviews

June / July 2010

World Premiere PrimaLuna DiaLogue Six Monoblock Power Amplifiers Worth every penny of their asking price. Review By Tom Lyle

When I'm shipped a piece of equipment such as the PrimaLunaDiaLogue Six monobloc I'm reminded that audiophiles are a lucky bunch to be participating in this "hobby" at this period of time. No matter what you choose (or do not choose) – analog or digital, dynamic or electrostatic, tube or solid-state – all of these contenders have advanced to the point that it is a matter of listener preference more than anything else. As far as tube amplifier design goes, auto-biasing that is used in many of the top manufacturers of these amps (including a more advanced type in the PrimaLuna), baby-sitting the tubes have become a thing of the past. But this feature would be of little use without the fact that at the same time the price-to-sound ratio (or simply, value) is getting so incredulously high that recommending cost-no-object gear, let alone on-the-high-side of mid-priced gear very difficult to justify.

Of course all of these things are great news for audiophiles, myself included, for reasons that should be obvious to all that are interested in everything audiophile, and of course in everything that has to do with enjoying our music to the nth degree. PrimaLuna has made their very fine tube gear available to more listeners simply by the fact that they are relatively affordable by taking advantage of the lower manufacturing costs in the Far East (and passing the savings on to the consumer. PrimaLuna's gear is designed in The Netherlands and then manufactured in China. Anyone who doubts that the Chinese are capable of building audio equipment to the most exacting standards that audiophile's should rightfully expect hasn't been paying attention of late. And as far as the expertise of the Dutch PrimaLuna company – if you are not aware that they design and sell high-value excellent sounding tube gear, you also haven't been paying attention. The $4699 a pair DiaLogue Six monoblock amps are one model from the more expensive top-of-the-line model Sevens, thus earning the Sixes the right to be considered high-value amplifiers.

Dangerously Close Even though the many claim that best gear these days gets dangerously close to the elusive ideal of absolute transparency, its fairly obvious that there aren't any amps (or audio components. Or recordings) regardless of cost that don't stray from this paradigm. So the best manufactures have figured out how to squeeze the most from a given technology at a given price point, and thus find ways of making trade-offs that attempt to bring

out the best in their gear.. And my experience with PrimaLuna gear has proven that they've succeeded in not only bringing out the best in tube technology and producing up with amps and other components with first-rate sonic qualities at a reasonable price. I would also be remiss in not adding that these are quite handsome looking pieces of kit, and especially the Sixes – that were quite impressive looking at that sat on their amp stands in front of the rest of my system. Their superbly constructed chassis are made of heavy gauge steel that are painted with a five-step "automotive quality" high-gloss black finish that is hand rubbed and polished,. The thick face plate can be ordered in either silver (as the review samples) or black. The removable tube cage, rather than hiding the tubes from view is constructed of vertical slats close enough together to prevent damage to the tubes (and the scorching of prying fingers), yet spaced far enough apart to get a clear view of the four EL34 output tubes and the two 12AX7 and 12 AU7 input tubes. The glass side panels of the cage further enhance the Six's cosmetics, and also does not obstruct the tubes and their comforting orange glow.

The PrimaLuna DiaLogue Six takes full sonic advantage of its tube birthright without very few disadvantages, and at the same time it can be considered a relative bargain in today's high-end. OK, I take that last thing back, because $4699 is not an insignificant amount of coinage – yet I'm hardly risking my reputation by saying that these amps can hold their own compared to amps costing much, much more than their asking price. And I'm also willing to risk that same reputation on the fact that one will hear a major improvement if upgrading to the PrimaLuna from an amp of a lesser pedigree. Included in the price of admission are a host of features, major among those is PrimaLuna's "Adaptive AutoBias" circuit that monitors and adjusts the tube's bias, thus making life a lot easier for someone like me who would like to spend time listening to music rather than spend time genuflecting to the amps with a power meter balancing on my knee. The advantages of the automatic biasing circuit, as designed by PrimaLuna (as opposed to the very remedial form of cathode bias used in less worthy amps), is that it increases the power efficiency of the amplifier plus lowers the levels of the already low levels of distortion. Plus, the circuit of the auto-bias used in the PrimaLuna is not in the signal path of the music. In addition, it is totally passive. The transparency and transient response also improves over the entire frequency range, including the bass as compared to amps with even more power than the amp under review. An even more impressive benefit of the PrimaLuna's automatic biasing is that the number of tube failures decrease, and almost more importantly, tube matching is a thing of the past so it also makes it possible to experiment with different types of tubes where the circuit will automatically adjust for just about any power tube on the market that will fit in the EL34-type sockets such as the 6550, KT88, KT90, 6L6GC, KT66, 7581, EL37, et cetera.

Besides it’s behind the scenes auto-biasing feature, the PrimaLuna Dialogue Six power amplifier can be switched between the more powerful ultralinear mode to triode mode from a remote control. Although I found that this remote function was made more useful when also using a remote control preamp because of the loss of volume that invariably occurred because of the amp runs at about half power in triode, still, it is a pretty nice feature, and the folks at PrimaLuna should be rewarded for this (of course an audition and

subsequent purchase is probably all the reward they're presumably looking for). More on the triode/ultralinear feature in a bit. Still, as nice as these features are, its internal features are where it’s at, and the Sixes hardly skimp on those.

The Six employs something PrimaLuna calls a "dual-feedback" topology, which they use cross-coupled current feedback, and at the same time apply a small amount of negative feedback to achieve an exact gain setting. This, claims PrimaLuna, provides low distortion and a low input impedance, but it also ends up canceling any negative effects that might crop up by using feedback in the first place but with all the benefits – which of course includes increased bandwidth. The Six is designed with a relatively uncommon type of output transformer, a dual-output model that PrimaLuna recently created that not only has a wide bandwidth, but losses very little current, and is meant to handle a much wider variety of speakers. A 2 Ohm output tap is added to the amp's 4 and 8 posts for additional flexibility, the 2 Ohm presumably for speakers of the electrostatic variety or others that might present a demanding load. Along with a tube plate fuse, the amps have a soft-start circuit which prevents the power from surging through the tubes, thus shorting their lives. The amps also are also constructed using premium parts, including chassis-mounted ceramic tube sockets (rather than cost-saving but flimsy plastic), Nichicon and Realcap capacitors, WBT-style speaker binding posts, and gold-plated input jacks. The wiring is, of course, point-to-point, and the like I stated before (and is worth mentioning again), the impressive looking chassis is made from a five-step automotive quality hand rubbed finished steel. The power transformer is a low hum "dead quiet" toroidal.

WonderfulAs you've read in many of my other reviews, I usually state at least once that a component might be only good as the system in which it is a part. By that I'm not trying to invoke the "weakest link in the chain" apophthegm (however truthful that might be). But lest one think that this review is simply a love letter to the DiaLogue Six monoblock, one should remember that not every piece of wonderful sounding gear is in my system going to sound wonderful in your system. And not only that, even if it will sound good, it has to fit your lifestyle. This is certainly true of the PrimaLuna Sixes because these amps are not the type of components that can't be hidden in a living room's chiffonier along with the television. These 15.2" x 8.3" x 16" monoblocks weigh in at 64 pounds each, need room to breathe, and take up a fair amount of floor space. And although I think they look ravishing with their gloss black cabinets with their glowing glass bottles lit up in the darkened listening room, one's life partner might not be as enamored with them as I am. But let's put all this aside for a moment and consider their strengths (not to mention my accepting wife) by noting that the sound quality of these amps are top notch in every department imaginable. At 70 Watts per channel in ultralinear mode these amps have enough power for most small to mid-sized speakers (and even some larger models). Each amp has binding posts for connecting speakers with an impedance of 8, 4, and 2 ohms to drive any real world speaker to sufficient volumes with rapturous results.

If one dared to judge the sound of tube amps solely on the PrimaLuna DiaLogue Six monoblocks one might wonder why the term "tube-y" was coined. Although it's pretty easy to look up on the Interweb and find that some audiophiles define the term as "an excess of warmth, exaggerated mid-bass, loss of upper-treble and deep bass, but with a lush midrange and expansive soundstage", the PrimaLuna Sixes, even though they sport eight tubes, other than the expansive soundstage part, do not fit this description. Have the designers of the DiaLogue Sixes found a way to eliminate every negative sonic stereotype and accentuate all the positives? Yes, quite possibly. Although it would be inaccurate to portray the PrimaLunas as being totally transparent, chiefly because I haven't heard any audio product that uses the EL-34 tube that doesn't inject at least a small amount of '34 warmth to the sound of the music, and this includes the PrimaLunas. I'm well aware that the venerable EL-34s have legions of fans (including me), but when describing the sound of these tubes when being used in the PrimaLuna DiaLogue Six as having an abundance of "warmth", I would only use this term to describe the beauty of music, as in the opposite of "sterile". These amps come awfully close to the paradigm of replicating recordings of real instruments recorded in a real space, as sonic illustrations of real instruments recorded in a real space. During the audition period it was awfully difficult to detect any variations from this archetype that wasn't caused by other components in the chain or the recordings themselves.to a low frequency response of 35 Hz (+/-3dB), their bass more than effectively gave a sense of what went on during the original recording session.

While the PrimaLunas were in this system I was much more likely to notice the sonic temperament of the speakers or the other associated gear, the PrimaLunas getting out of the way and simply amplifying the signal without adding any characteristics that couldn't be described as, again, musical. This led the focus to be on the music (and the recording, I'm afraid), so during the furious 16th notes that open the second movement of this symphonic essay exposed the multi-mic technique of the recording engineers. Now that this modern method of recording seems to be de rigueur, I've become accustomed to the democratization of the orchestra as portrayed on just about every modern classical CD I've purchased or otherwise acquired for almost as long as I can remember – so a mixing engineer's heavy hand on the mixing console balancing the relative levels of the instruments in addition to the conductor and the musicians doing this for themselves doesn't bother me nearly as much as it once did. Although it does render the expansive soundstage a bit on the man-made side of things, the Saint Louis Symphony Orchestra as led by David Robertson was still laid out between and beyond the speakers in a coherent manner. When the complex score quiets down about ten minutes into the second movement, the winds and strings take become quite literally center-stage, rarely has the overused term "palpable presence" been more applicable. The instruments hung in space between the two speakers in a nearly three-dimension diorama of sound.

Switching gears I put on some smaller scale music, some selections from the amazing four CD set of John Coltrane's The Complete 1961 Village Vanguard Recordings that comprise every note that was played between November 1st and 5th, 1961 by his legendary band. As much as I respect every recording that engineer Rudy Van Gelder has ever made, that has more to do with the subjects of his art than his recording arts in itself. The hard panning, ultra-close mic'ing, ofttimes limited frequency response, and questionable techniques when recording the piano often plague Mr. van Gelder's recordings, and yet the quality rarely distracting, and to be truthful, some are outstanding recordings regardless. And that goes for this CD set, which finds John Coltrane playing both tenor and soprano sax in top form in the later period of his career when he was signed to Impulse Records. When playing one of the now legendary versions of the pianolessChasin' the Trane, one without alto-saxophonist Eric Dolphy, the PrimaLunas enable one to follow Coltrane's lines to the near impossible feat of imagining one is inside his head, so to speak. Every inflection created by his amazing breath control, and every convoluted line coming forth from his ostensibly magical improvisational style is transported through to the speakers exactly as it appears on the extraordinary mastering of these Red Book CDs. Rarely have I hear his instrument's harmonic texture so expertly reproduced.

Of course the magic of a properly engineered tube amplifier lie in its proficiency in rendering of the midrange frequencies, and the PrimaLunas do not disappoint in this area. I could have easily spent the entire review discussing the unmatched beauty of the Six's reproduction of all sounds that have significant energy within these frequencies – and since there a few instruments that do not have significant energy in this most important of frequency ranges, this bodes well for the listener. Vocals are especially well served, and whether I was listening to male or female in large groups or small, and regardless of musical genre, the vocals came through the speakers as if I was eavesdropping on the recording session.

This is as good a time as any to discuss the PrimaLuna's ability to switch between ultralinear mode, in which the amp puts out 70 Watts per channel in ultralinear, and in triode mode 40 Watts per channel. The manual states that when one listens to the amp in triode mode one should hear a sound "best described as warmer on top and bottom, a little compressed, with the midband now slightly more pronounced". Since I did not try these amps in triode for a super-long amount of time, I'm not sure that I'm one to fully judge whether triode mode is "better" than ultralinear. But I know what I like. When I used the DiaLogue Six when in triode mode through either the Dynaudio or Salks at normal listening levels it wasn't that appealing – most of what I like about the PrimaLunas were gone, and in its place a more colored, less lively sound. At low volumes with simple material it was OK, but this was not how I perform serious listening. And even when listening to the Sixes playing in the background music the loss of definition bothered me. The owner's manual spends quite some time discussing the difference between the two modes, and stresses that one should "never let people tell you what sounds right". And so I won't either. But what I will say is that it is quite nice that one has the choice of eitherultralinear or triode operation, and that the switch is available on a remote is quite a nice touch.

AssumedLastly, I should address the fact that most should be aware that PrimaLuna's current top-of-the-line DiaLogue Seven has been reviewed quite favorably in the audiophile press, and, I've always assumed that it is more popular than the Six. Or maybe not. It wouldn't be fair (or honest) to compare these two amplifiers without the two models connected side-by-side. But if you ask me to choose between the Six' using EL-34 or KT88s, I wouldn't be going too far out on a limb if I chose the Six with its '34s (not for a moment slighting any amp that uses the KT-88 tube). Admittedly, I've used far more amplifiers using the EL-34 more than the KT88. According to Kevin Deal, PrimaLuna's US distributor, the DiaLogue Sixes are the exact same amplifiers as the DiaLogue Sevens except the Sevens have Solen capacitors, fast-recovery diodes, and obviously, KT88 power tubes. Of course, one is free to use KT88s in the Sixes. The KT88s might have more treble energy than the EL-34s when used in most systems, but in the system using either the Dynaudio or Salk speakers the Sixes sounded much better using EL-34s. The KT88s sounding a bit "brittle" in comparison. But much like ultralinear vs. triode mode I'd be a fool to say that one tube is "better" than the other, just that I prefer one more than the other. Plus, one can save some money by choosing the Six. I, for one, would never second guess your decision. And neither should you.

Specifications Type: Vacuum tube stereo amplifier Output: 70 watts ultralinear, 40 triode Tube Compliment: Two 12AX7 and two 12AU7 and four EL34 Frequency Response: 10 Hz to 100 kHz (+/- 3dB) THD: Less than 0.25 percent @ 1 watt, SNR: 83dB Input Sensitivity: 1.1V Dimensions: 15.2" x 8.3" x 16" (WxHxD) Weight: 63.8 lbs Inputs: 1 single RCA Outputs: 2, 4 and 8 Ohm speaker taps Price: $4699

Company Information United States Distributor PrimaLuna USA 1042 N. Mountain Ave #B PMB 406 Upland, CA. 91786

Phone: (909) 909-931-0219 Fax: (909) 985-6968 Website: http://www.primaluna-usa.com

DiaLogue Seven Reviews



DESCRIPTION Monophonic tube amplifier with push-pull output stage. Tube complement: two 12AX7, two 12AU7, four KT88. Maximum output power: 40Wpc in triode mode (16dBW into 8 ohms, 70Wpc in ultralinear mode (18.45dBW into 8 ohms), both at 2% THD. Frequency response: 10Hz–100kHz, ±3dB. Input impedance: 100k ohms. Output impedances: 2, 4, 8 ohms. Signal/noise: >84dB unweighted (no reference level given). Total harmonic distortion: <0.25% at 1W, 2% at rated power.DIMENSIONS 15.2" (385mm) W by 8.3" (210mm) H by 15.9" (405mm) D. Weight: 63.8 lbs (29kg).SERIAL NUMBERS OF UNITS REVIEWED 08073916, L & R.PRICE $4999/pair. Approximate number of dealers: 11, also sold direct. MANUFACTURER Durob Audio BV, PO Box 109, 5250 AC Vlijmen, The Netherlands. Tel: (31) 73-511-25-55. Web: www.primaluna.nl. US distributor: PrimaLuna USA, 2504 Spring Terrace, Upland, CA 91784. Tel: (909) 931-9686. Web: www.primaluna-usa.com.

ART DUDLey

PrimaLunaDiaLogue Sevenpower amplifier

Step 1: Find something that works. Step 2: Use it. Step 3: Repeat as necessary, then retire.

That doesn’t work everywhere—the arts are inhospitable—but for those with less lofty goals, it’s nice to have a formula, especially a good one. The people behind the PrimaLuna line of audio electronics prob-ably know that as well as anyone. A few years ago they combined a unique amplifier design with a similarly distinctive business model to

create the ProLogue One, a product known for both value and reliability: the former by combining Chinese assembly with European (in this case, Dutch) quality, the latter for a circuit innovation that made the thing darn near foolproof.

The formula has been applied, with apparent success, to a number of subsequent products, the latest being the PrimaLuna DiaLogue Seven monaural tubed amplifier ($4999/pair), which offers 70Wpc in ultralinear mode or 40Wpc when run as a triode amp—and does so in a mildly remarkable way.

DescriptionAs with earlier PrimaLuna amplifiers, the DiaLogue Seven’s calling card is a circuit innovation called Adaptive AutoBias. The term auto bias normally describes a circuit in which the signal grid of a power tube is referenced to ground, and the potential

PrimaLuna DiaLogue Seven monoblock power amplifier


P R I M A L U N A D I A LO g U E S E V E N M O N O B LO C k

of the cathode is raised above ground through a cathode resistor,1 thus prompt-ing the tube to adjust itself under oper-ating conditions. PrimaLuna’s variation of the name refers to something differ-ent: a fixed-bias amp in which the volt-age applied to the signal grid is adjusted, minutely and continuously, in response to such variables as operating tempera-ture and input-signal amplitude. Thus the Adaptive AutoBias circuit, central to which are a microprocessor and other silicon bits, keeps the output tubes oper-ating within their best parameters at all times—which, according to PrimaLuna, provides significant reductions in both distortion and tube wear. The circuit is also said to allow greater-than-usual flexibility in swapping tubes, in terms of

both age and tube type, while keeping performance on an even keel. I’m told that one can even use in the DiaLogue Seven different ages or types of tubes for the two sides of a single complementary pair, for the sheer jaunty fun of it.

Another innovation distinguishes this new PrimaLuna amp from the compe-tition—and, in this instance, from the company’s humbler ProLogue series: Not only can the DiaLogue Seven be run in either triode or ultralinear mode, but the user can switch between those modes at will, with the push of a but-ton on a remote handset (included). The late, great Peter Snell, who devised some clever ways to adjust crossover parameters from his listening seat in an effort to perfect his loudspeaker designs, is surely smiling upon this.

When I opened the DiaLogue Seven’s chassis for a look inside, the key to its dual-mode design surprised me. (Had I

given it just a bit more thought, I might have figured it out when I first lifted the amp from its sturdy triple carton—and noted its 71-lb-per-channel shipping weight.) Each monophonic DiaLogue Seven contains one mains transformer and two complete output transformers. In triode mode, of course, the screen grids of the KT88 pentode tubes are tied to the plates, and the tubes operate as in-directly heated triodes. But in ultralin-ear mode, the screen grids are tied to a portion of the primary windings of the output transformer, in a distortion-can-celing scheme that functions rather like feedback. Because that requires tapping the primary at a very specific ratio, the luxury of an extra output transformer on an amp such as this is a Godsend.

In other ways, the PrimaLuna Dia-Logue Seven is comparatively straight-forward: solid-state rectification and a robust pi filter for the power supply, along


I examined the PrimaLuna DiaLogue Seven’s measured behavior using Stereophile’s loaner sample of the top-of-the-line Audio Precision SyS2722 system (see the January 2008 “As We See It” and www.ap.com);

I also used my Audio Precision System One Dual Domain for some tests. With three output-transformer taps and two output operating modes (triode and ultralinear), the DiaLogue Seven offers six choices of how it can be used. I performed a complete set of measurements from each tap in triode and ultralinear modes, but have published here only a limited selection of the graphs to illustrate the points I want to make.

The PrimaLuna preserved absolute polarity (ie, was non-inverting) from all transformer taps in both ultralinear and triode mode. As expected, however, the gain varied according to both mode and tap. In ultralinear mode, the voltage gain into 8 ohms was 26.9, 26.3, and 24.8dB, from the 8, 4, and 2 ohm transformer taps, respectively. In triode mode, the corresponding figures were 23.5, 22.1, and 20dB. even with the generally low gain, however, the preamplifier used with the DiaLogue Seven won’t be asked to deliver more than 1.5V RMS to drive the amplifier to its maximum output.

The Dialogue Seven’s input impedance was very high, at around 100k ohms in the bass and midrange, dropping to a still-high 70k ohms at the top of the audioband. High is good for a component’s input impedance, as this means it won’t load down the source component’s output in any significant way. High is not good for a component’s output impedance, however, and, as with other PrimaLuna amplifiers Stereophile has reviewed, the DiaLogue Seven’s output impedance was indeed high. In the worst case, ultralinear mode from the 8 ohm tap, the impedance was 8 ohms across the audioband. Triode mode dropped this to a still-high 4.3 ohms, and in general, changing to an output transformer tap with half the nominal impedance halved the output impedance in both

ultralinear and triode modes. In the best case, triode mode from the 2 ohm tap, the PrimaLuna’s output impedance was 1.2 ohms, which is still quite high in absolute terms.

The justification for designing an amplifier to have a high output impedance is that the maximum transfer of power occurs when the output impedance is equal to the load impedance. An 8 ohm impedance feeding an 8 ohm load transfers more power to the load than would a greater or smaller impedance. However, there is a price to be paid: because loudspeaker impedances vary considerably with frequency, high output impedances result in significant modification of the amplifier’s frequency response, due to the Ohm’s Law interaction between the amplifier and loudspeaker impedances. This is illustrated by the gray trace in fig.1, which shows the DiaLogue Seven’s frequency re-sponse from the 4 ohm tap in ultralinear mode into Stereo-phile’s standard simulated loudspeaker. The response varies by up to ±2.1dB, which will be audible. From the 8 ohm tap (not shown), the response variation was ±3.2dB, which will be very audible. Three other things can be seen in

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Fig.1 PrimaLuna DiaLogue Seven, ultralinear, 4 ohm tap, frequency response at 2.83V into: simulated loudspeaker load (gray), 16 ohms (magenta), 8 ohms (blue), 4 ohms (red), 2 ohms (cyan). (1dB/vertical div.)

1 The presence of a cathode resistor is not itself a sign of auto bias: A very-low-value resistor here makes it possible for a technician to measure and adjust his out-put tubes yet still run them in fixed-bias mode.



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Fig.2 Rogue M-180, triode, 8 ohm tap, frequency response at 2.83V into: simulated loudspeaker load (gray), 16 ohms (blue), 8 ohms (cyan), 4 ohms (magenta), 2 ohms (red). (1dB/vertical div.)

with parallel 12AX7 tubes and a long-tail pair of 12AU7 tubes for the input/driver section. But in one other regard the amp is far from ho-hum: the quality and care with which it’s made. Apart from the above-mentioned AutoBias circuit and the logic bits for the remote control, the DiaLogue Seven is completely hand-wired, point to point—and I’ve never seen a better-built amp. Wires were neatly trimmed and dressed, with no strand out of place. I spent a long time trying to find a single bad solder join, and could not: Someone made this as if it mattered.

Installation and setupThe DiaLogue Seven’s input and output characteristics suggest good installation flexibility, the former by its 100k ohm im-pedance (and apparently generous gain), the latter by its choice of loudspeaker connections: 2-, 4-, and 8-ohm secondar-ies. As for that, I played the PrimaLunas

through two very different loads: my usual Audio Note AN-E SPe HE (for High Efficiency) loudspeakers, and a bor-rowed pair of Wilson Audio Specialties Sophia 2s, recently and expertly installed by Wilson’s Peter McGrath. My original

intention was to try the DiaLogue Sevens with my rebuilt Quad ESLs, as well: Re-grettably, I wasn’t able to do that within this initial review period, but PrimaLuna USA is allowing me to keep the review samples a little longer than usual, during which time I’ll try the Quad option.

The DiaLogue Sevens weren’t fussy about placement—a nice thing to say about any pair of amplifiers that together weigh more than some adults—and for the most part I kept them on my hardwood floor, without benefit of isolation tweaks. They

became warm during use but not alarm-ingly so; their elegant-looking tube cages, held neatly in place with banana-style bay-onet connectors, provided ample protec-tion, amp from user and user from amp.

Notwithstanding unrectified current on all tube heaters, the Sevens never

fig.1: first, the DiaLogue Seven features a wide small-signal response that doesn’t begin to roll off until >60kHz; second, in ultralinear mode, there is a sharply defined resonant peak around 150kHz, though the height of this peak drops a little with decreasing load impedance; and third, a low-frequency peak starts to develop into lower impedances.

Fig.2 shows the PrimaLuna’s response from the 4 ohm tap but with the amplifier now in triode mode. The varia-tion into the simulated loudspeaker is now ±1.25dB, due to the lower output impedance in this mode, and there is now just a vestigial peak around 150kHz. There is also no sign of any lower-frequency peak, and the response is maintained to well above the audioband. At the other end of the spectrum, the low-frequency response starts to roll off below 40Hz, but is still down only 1.4dB at 10Hz. These are well-designed output transformers, the DiaLogue Seven’s reproduction of a 1kHz squarewave in triode mode being extremely square, with flat tops and almost no ringing (fig.3). Similarly, a 10kHz squarewave in triode mode offers only small degrees of overshoot

and ringing, with very short risetimes (fig.4), whereas in ultralinear mode (fig.5), both overshoot and ringing are considerably more developed, this correlating with the ultrasonic peak in the frequency response.

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Fig.4 PrimaLuna DiaLogue Seven, triode, 8 ohm tap, small-signal 10kHz squarewave into 8 ohms.

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Fig.3 PrimaLuna DiaLogue Seven, triode, 2 ohm tap, small-signal 1kHz squarewave into 8 ohms.

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Fig.2 PrimaLuna DiaLogue Seven, triode, 4 ohm tap, frequency response at 2.83V into: simulated loudspeaker load (gray), 16 ohms (magenta), 8 ohms (blue), 4 ohms (red), 2 ohms (cyan). (1dB/vertical div.)

wires were neatly trimmed and dressed, with no strand out of place. i spent a long time trying to find a single bad solder join, and could not: SOMEONE MADE ThIS AS IF IT MATTERED.



hummed—another testament to their excellent layout and con-struction. There were no un-wanted noises of any sort, in fact, except for a soft and apparently harmless click that I heard when using the remote control to switch between triode and ultra-linear modes (which, incidental-ly, is the handset’s only function). The only problem I experienced was when the handset became taciturn, seemingly overnight, and would no longer work from distances of greater than a foot. I attempted a battery change, but became listless my-self when I saw that the battery was an oddball disc type, and not the sort that I keep around the house.

ListeningAn enthusiast of low-power amps, I didn’t think I’d like the DiaLogue

Seven’s high-power ultralinear mode as much as its low-power triode mode. I imagined the former would sound smaller and fussier, more mechanical, and altogether more hi-fi than I prefer. I was wrong. Among other things, music through the PrimaLunas in ultralinear

mode sounded every bit as large and present as through my Shindo Haut-Brion, itself a low-power amp in which pentode tubes are wired as triodes, but operated with a very small amount of

global feedback.In ultralinear mode the DiaLogue Seven was stun-ningly dramatic through both loudspeaker pairs. Georg Solti and Leon-tyne Price’s recording of Verdi’s Aida (LP, RCA

Living Stereo LSC-6158) was intensely involving, from the great or-chestral and choral tuttis of Act I, Scene 1 (“Guerra! Guerra! Guerra!”) to those at the end of Act IV, Scene 1 (“Tradi-tor! Traditor! Traditor!”). At the other end of the spectrum, the dynamic peaks within Jeremy Backhouse and the Vasari Singers’ recording of Herbert Howells’ motet Take him, earth, for cherishing (CD,

I experimented with the grounding between the DiaLogue Seven and my test equipment, but couldn’t eliminate a very low level of power-supply noise. The wideband, unweighted signal/noise ratio was therefore good rather than great, at 66.6dB (ref. 2.83V into 8 ohms) from the 8 ohm tap, this improving slightly from the lower-impedance transformer taps. A-weighting the measurement improved the S/N ratio to 83dB.

Figs.6–11 show how the THD+noise percentage in the PrimaLuna’s output varies with output power into loads ranging from 2 to 16 ohms. Figs.6–8 were taken in ultra-linear mode from the 8, 4, and 2 ohm taps, respectively; figs.9–11 were taken in triode mode. PrimaLuna specifies the DiaLogue Seven’s maximum output power at 2% THD rather than the more usual 1%, and you can see from a close inspection of these graphs that, when the load is matched to the nominal value of the transformer tap, the amplifier does meet its specified power outputs of 70W in ultralinear mode (18.45dBW into 8 ohms) and 40W in triode mode (16dBW into 8 ohms) at 2% THD. The lowest

distortion at lower levels is obtained when the load is much higher than the output tap used, and the amplifier is at its most linear from the 2 ohm tap in ultralinear mode, with around 0.07% THD+noise typical below 1W. However, triode

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Fig.6 PrimaLuna DiaLogue Seven, ultralinear, 8 ohm tap, distortion (%) vs 1kHz continuous output power into (from bottom to top): 16, 8, 4, 2 ohms.

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Fig.5 PrimaLuna DiaLogue Seven, ultralinear, 4 ohm tap, small-signal 10kHz squarewave into 8 ohms.


Cutline QQQ



United 88033) were consistently mov-ing while never sounding harsh or me-chanical. Lines of notes had very good momentum and flow, and vocal colors were fine.

In triode mode the DiaLogue Seven sounded softer overall, with a little less sparkle in its upper octaves—yet with more midrange texture, which can im-part a sense of natural presence and de-tail even in the absence of an extended treble range. Similarly, in triode mode the DiaLogue Seven offered less bass content and impact than in ultralinear, as I especially noted when listening to César Franck’s Grande pièce Symphonique, Op.17, performed by organist Torvald Torén (LP, Lyricon LRC 2-5)—which itself didn’t have the floor-rattling capa-bilities of either the Haut-Brion or the ultralinear but feedback-free Shindo Corton-Charlemagne monoblocks.

My preconceptions were soon con-

founded in another way: I thought the DiaLogue Seven’s comparatively soft, tubey triode mode would yield poorer temporal performance—musical timing, momentum, and the like—than its ultra-linear mode. Again, that wasn’t so. With

the amps in their low-power mode, I very much enjoyed the final movement of Beethoven’s Symphony 4 with Pierre Monteux and the London Symphony Orchestra (LP, Victrola/Classic VICS-1102)—a performance that lives or dies on the ability of one’s gear to not muck

up the timing. It sounded dazzling, as it should.

The same held true with pop music. As expected, the DiaLogue Sevens’ triode mode helped tame overly crisp record-ings, such as “Already Dead,” from Beck’s

Sea Change (LP, Geffen B00004372-01). Low-frequency note attacks were also softened on that and other tracks from this album—but, again, I was surprised to hear little or no timing distortion on up-tempo songs that depend on kick drum and electric bass for their sense of drive.

IN TRIODE MODE ThE DIALOgUE SEVEN SOUNDED SOFTER OVERALL, with a little less sparkle in its upper octaves—yet with more midrange texture.

mode is considerably less linear than ultralinear, reaching 1% THD around 10W from every tap into every load.

The traces in the six preceding graphs were taken at 1kHz. Plotting the THD+N percentage against frequency

revealed that the amplifier’s small-signal linearity decreased at both high and low frequencies. Fig.12, for example, was taken in ultralinear mode from the 4 ohm tap, and while the amplifier is obviously more comfortable driving


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Fig.11 PrimaLuna DiaLogue Seven, triode, 2 ohm tap, distortion (%) vs 1kHz continuous output power into (from bottom to top): 16, 8, 4, 2 ohms.

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And though this falls afield of my usual performance notes, I can’t resist mention-ing the nearly unique clarity and direct-ness—and the latter certainly is a quality I associate with low-power triode amplifi-ers—that the triode-mode DiaLogue Sevens brought to the Sprechgesang in Karl Böhm and Dietrich Fischer-Dieskau’s famous recording of Berg’s Wozzeck (LP, Deutsche Grammophon 2707 023). Many lines had me jumping in my seat, wondering why there were Germans in the house.

Which mode did I most enjoy? As much as the ultralinear mode earned my respect—and, in a number of ways, surprise—I ultimately preferred the Dia-Logue Sevens’ triode mode with both the Audio Note and Wilson speakers. Even on large-scale music, though the amps seemed more effortless in high-power mode, they compressed the peaks more gracefully in low-power mode, and conse-

quently sounded slightly less mechanical overall. A fine example of that was on the song “Sabbath Morning at Sea,” from Ja-net Baker and John Barbirolli’s recording

of Elgar’s Sea Pictures (LP, EMI ASD 655): the London Symphony Orchestra’s un-mistakably Wagnerian crescendo was less sweaty in ultralinear, but somewhat more

ASSOCIATED EQUIPMENTANALOg SOURCES Thorens TD-124 Mk.II turntable; eMT 997 tonearm; Shindo SPU, Ortofon SPU 90th Anniversary, eMT OFD 25 & OFD 65 cartridges.DIgITAL SOURCES Sony SCD-777eS SACD/CD player, HRT Music Streamer+ USB DAC (with Apple iMac).PREAMPLIFICATION Auditorium 23 Hommage T1 step-up transformer, Shindo Masseto preamplifier.POWER AMPLIFIERS Shindo Haut-Brion & Corton-Charlemagne monoblocks.LOUDSPEAkERS Audio Note AN-e/SPe He, Wilson Audio Specialties Sophia Series 2.CABLES USB: Belkin Pro. Interconnect: Audio Note AN-vx, Shindo Silver. Speaker: Auditorium 23. AC: JPS Labs The Digital (SACD/CD player).ACCESSORIES Box Furniture Company rack (source, amplification components); Vertex AQ Super Kinabalu platforms; Keith Monks RCM record-cleaning machine.—Art Dudley


higher impedances, the distortion increases dramatically into all the loads below 100Hz. The change in behavior with different loads is less extreme in triode mode (fig.13), though the overall distortion is considerably higher than in ultralinear mode.

Fortunately, as with the Rogue tube amplifier also re-viewed this month, the distortion at low levels is heavily second-harmonic in content (fig.14), though narrowband spectral analysis indicates that the third and fifth harmon-ics are also present, as well as the power-supply spuriae mentioned earlier (fig.15). At higher powers, the third harmonic rises almost to the level of the second, with now a regular series of harmonics apparent (fig.16).

Though the DiaLogue Seven is less linear at high frequencies than in the midrange, the amplifier did quite well on the high-frequency intermodulation test. At a level just below visible waveform clipping on the oscil-loscope, both the second-order difference tone at 1kHz and the higher-order tones at 18 and 21kHz lay at –52dB (0.25%) in ultralinear mode (fig.17), and –46dB (0.5%)

in triode mode (not shown). At low powers (fig.18), the difference tone dropped to –66dB (0.05%) and the higher-order products almost disappeared.

When I measure amplifiers like PrimaLuna’s DiaLogue

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Fig.14 PrimaLuna DiaLogue Seven, ultralinear, 8 ohm tap, 1kHz waveform at 2W into 8 ohms (top), 0.154% THD+N; distortion and noise waveform with fundamental notched out (bottom, not to scale).

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Fig.12 PrimaLuna DiaLogue Seven, ultralinear, 4 ohm tap, THD+N (%) vs frequency at 2.83V into: 16 ohms (blue), 8 ohms (red), 4 ohms (cyan), 2 ohms (magenta).

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Fig.13 PrimaLuna DiaLogue Seven, triode, 4 ohm tap, THD+N (%) vs frequency at 2.83V into: 16 ohms (blue), 8 ohms (red), 4 ohms (cyan), 2 ohms (magenta).



mechanical, too; smoothness, albeit with appropriate amounts of believable string texture, was greater in triode mode.

Where did the DiaLogue Sevens fall down? Nowhere, really. They commit-ted no errors of addition, failing only to give even more of those things I love, available for a price from a few other sources: the more saturated timbral col-ors of a Shindo Corton-Charlemagne, the greater bass grip of a Naim NAP250, the even greater psychedelic presence of solo instruments and voices of a Fi 2A3 Stereo. Yet the PrimaLunas were more than satisfying in all those regards, and consistently impressed me with their flexibility and, perhaps more important, their value.

ConclusionsWith each passing year, the products we buy seem more intimately tied to the cir-

cumstances of their creation. In a free so-ciety, it’s okay to buy whatever we want. That said, it’s also okay to be more selective than that, if you feel the need. For consum-ers as for everyone else, it’s okay to care.

I’ll bet PrimaLuna has that figured out, too, because it seems they’ve made peace with who they are: a company

that could not offer such a combination of performance quality, build quality, and value without having some of their manufacturing done in China.

To some, those are dangerous ideas. To me, the most dangerous idea of all was

right there on page 8 of the DiaLogue Sev-en owner’s manual: “Have fun with [this amp] and never let people tell you what sounds right.” I couldn’t agree more.

From my experience, the DiaLogue Seven succeeds at everything PrimaLuna set out to do: It’s an apparently reliable, obviously wonderful-sounding amp that

offers higher-than-average value—and a lovely opportunity for you to discover the playback approach that suits your ideas about recorded music while, at the same time, having fun. Very strongly recommended. nn

Seven, my eyebrows always rise because the things they do wrong must be balanced against the possible sonic befits of the other things they do. Certainly, the designer’s decision to use very high output impedances will drastically affect

sound quality for reasons that are well understood. The DiaLogue Seven’s measured performance in triode mode was notably worse than in ultralinear mode, yet Art Dudley ultimately preferred triode mode. A puzzle.—John Atkinson

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Fig.17 PrimaLuna DiaLogue Seven, ultralinear, 4 ohm tap, HF intermodulation spectrum, DC–24kHz, 19+20kHz at 26W peak into 8 ohms (linear frequency scale).

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Fig.18 PrimaLuna DiaLogue Seven, ultralinear, 4 ohm tap, HF intermodulation spectrum, DC–24kHz, 19+20kHz at 1W peak into 8 ohms (linear frequency scale).

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Fig.16 PrimaLuna DiaLogue Seven, ultralinear, 8 ohm tap, spectrum of 1kHz sinewave, DC–1kHz, at 30W into 8 ohms (linear frequency scale).

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Fig.15 PrimaLuna DiaLogue Seven, triode, 4 ohm tap, spectrum of 1kHz sinewave, DC–1kHz, at 1W into 8 ohms (linear frequency scale).

the primalunas consistently impressed me with their flexibility and, PERhAPS MORE IMPORTANT, ThEIR VALUE.

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The PrimaLuna DiaLogue Sevens

CAN WE TALK?

By Hood McTiernan

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But wait, there’s more! These amplifiers feature an innovative Adap-tive Autobias (TM) circuit that contin-ually monitors the output tubes and keeps them in peak operating range. No matched quads required here; the amp takes care of itself in that regard. For you tube rollers out there (and you know who you are), this amp allows for just about any output tube to be plugged in and enjoyed. If your favorite output tube flavor runs toward EL-34s, 6550s, 6L6s, or 7581s, you’re good to go. This handy circuit will automatically adjust for the new tube’s characteristics and auto-matically set bias. Whether you are new to tubes or a veteran, it doesn’t get any easier than this.

Tube Magic and a Few Tweaks

The PrimaLunas are a pleasure to listen to. These amps are the polar opposite of my Jeff Rowland 201s. The 201s manage to extract excellent performance from ice-Power modules while the DiaLogue Sevens rely on ancient technology with some clever modern twists to create their magic. The first thing you’ll notice is the lush dimensional-ity of the midrange, a characteristic of most tube amps. Being a lover of horns in jazz and classical music, I was very taken with their ability to reproduce the roundness and the blat of certain instruments without any annoying glare or blare.

The tweeter on the Diablo Uto-pias is very revealing, but I could not find anything at all to take issue with at the top end. Cymbals had the requisite splash but they also had beautifully rendered shimmering decay. At the bottom end, the pluck of stand-up bass and the slap and pop of an electric bass were deliv-ered in a more weighty manner than I thought possible on my speakers. (continued)

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haven’t had a tube amp in my system for quite

a while, and I was looking forward to revisiting

bottle heaven with the arrival of the PrimaLuna

DiaLogue Seven monoblocks. My last pair of

tube monos were Audio Research VTM-120s,

which have been sorely missed. And while

I haven’t ever lusted after a Chinese-made

component for my system, I had no qualms

regarding expected quality, as PrimaLuna has

an excellent reputation of six years.

However, it is a slightly different story with these amplifiers: they are designed in the Neth-erlands and built in China, with Upscale Audio as the U.S. distributor. And what a design they are. First off, the fit and finish is first rate. The painting on the chassis, the look of the metal-work and the stylish cages make for an interest-ing presentation indeed. Throw in the fact that they have some unusual and innovative features to go along with their more-than-impressive per-formance, and you have a formula for success from a music lover’s perspective.

All the Right Qualities

There’s a lot of goodness in the build sheet here. Four modern production copies of the re-vered Genelex KT88 output tube plus two each of 12AX7s and 12 AU7s adorn the front of each chassis. There are some specially designed wide-band, low-loss output transformers resid-ing at the back of the chassis covered by a steel enclosure. These transformers are good enough to enable the amp to deliver rated output into a 2-ohm load. Add point-to-point wiring, premium Solen caps and fast-recovery diodes, and the value-for-money factor gets better and better.

Using four KT88s to deliver 70 watts makes for an unstressed output stage. I remember years back when I had Quicksilver Monos that extracted 90 watts from a single pair. Did I men-tion that they weigh a hefty 64 pounds apiece? Now that’s heavy metal.

I

(continued)

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As with the horns, vocals were lush yet detailed and never an-noying or in your face. Add to all of these great attributes a huge sound stage and ole Hood was a very happy camper.

You often hear reviewers refer to rhythm and pace when re-viewing products but never groove. Well I’m here to attest that these amplifiers find the pocket and hold down the groove in a most seductive manner.

But in spite of all the enjoyment, I knew these amplifiers could provide even more performance. Not being able to leave well enough alone, I started with replacing the stock power chord with a lower-end Shunyata model. Things got marginally better from a noise standpoint and the music was a bit more focused. Stepping up to one of the big dogs in the Shunyata lineup, the Python CX, paid big dividends in the quietness of the background and the abil-ity to see into recordings better with far more bottom-end slam.

The next step was to add a Shunyata Hydra 2 at the back of each amp. Now we’re talkin’! That was followed by placing each amplifier on a nice chunk of spiked and damped granite. Finally, I added an HRS damping plate to each of the steel enclosures on the amps. This might sound like a lot of trouble and expense to go through for amps that sound quite excellent on their own, but for the intrepid tweaker, there’s more to be had in this dialog, much more. After all of these tweaks, I was totally enamored of what I was hearing from these amplifiers. Then … there was the one thing left to try.

Exploring Triode Mode

The DiaLogue Seven can operate either in 70-watt Ultralinear mode or 40-watt Triode mode. The user can change modes via the cool little remote supplied with the amplifiers. For the first three weeks of this review, the amps operated solely in the Ultra-linear mode. I had assumed that the Triode mode just couldn’t deliver the goods in my situation. And mostly, I was right. But my, oh my, pushing that little button was a revelation. As long as I kept the volume at a reasonable level, the pure musical enjoy-ment delivered by these amplifiers was mighty fine. The sound stage became wider and deeper, transparency increased and from the mid-treble region on up, there was a seductive rightness that was certainly attention grabbing. If you have very effecient speakers in the 91+ dB range, here's your amplifier. Every time I pressed the button, I was reminded of the machine in Woody Allen’s Sleeper called the Orgasmatron. Step into the machine, press the button and, well, you know. (continued)

If you have very effecient speakers in the 91+ dB range, here’s your amplifier.

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The only tweak left was to experiment with tubes in the input stage. I didn’t go there but was sorely tempted. But I do wonder what nos Mullard or Amperex tubes could do in that part of the circuit. Maybe some other time.

Try as I might, I could find little to criticize about the sound of these amplifiers. Are they the most transparent amps ever? No. Do they have a strangle hold on the woofers? No. Blackest back-ground? No. But to be honest, I didn’t really care about these minor quibbles because the whole presentation was so enjoyable. During my time with these amplifiers, I found myself asking over and over how PrimaLuna can deliver so much greatness for such a reasonable price. I would guess that savvy design, savvy pro-duction techniques, unique circuitry, cost-effective production-site choice and other intelligent decisions yield a compelling product. Time and again,, my better half overheard me asking, “How do they do that”? When prompted, I just explained that these ampli-fiers had me talking to myself. Very highly recommended.

I found myself asking over and over how PrimaLuna can deliver so much greatness for such a reasonable price.

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id someone say tube rolling? Having used various PrimaLuna amplifiers over the years (And my ProLogue 1 runs flawlessly since day one, with only one recent set of fresh tubes after six years), I ran the DiaLogue monos through a few more scenarios, with excellent results.

If you haven’t read any of our past reviews on Pri-maLuna amplifiers over the years, I’m a big fan of the marque. The build quality is excellent, the failure rate is zero and these amplifiers are easy to customize to your system and/or listening tastes. If you desire the sound of a contemporary tube amplifier, go with the stock KT-88’s to get punch and bass extension. If you are willing to sacrifice a few watts for scrumptious midrange, roll in a set of EL-34 tubes. And for those of you that still love the sound of your McIntosh MC-30’s and MC-40’s, go for broke with a set of 6L6GT’s and replace all of the driver tubes with your favorite Mullards, and you’ll swear you went back in time.

versatile Performers

I kept the DiaLogues much longer than the usual week to take photos, so I could thoroughly break them in as well as try them with about 15 different speakers. The DiaLogue Sevens would drive everything I threw at them, from the 84db ACI Sapphire XL’s up to the 100db ZU Presence. The Zu’s were absolute magic in Triode mode; I probably never used more than about 3 of those 40 watts per channel driving the Zu’s.

Thanks to the 2-ohm tap that McT mentioned, you can even drive a pair of MartinLogans with them fairly well. The CLX, Spire and Summit X were no problem at modest levels, without the highs being rolled off as they do with some of my favorite tube amplifiers.

With their high build quality, great sound and versatility, we are happy to give the PrimaLuna DiaLogue Sevens one of our Exceptional Value Awards for 2009. – Jeff Dorgay

Further Listening:

D

prologue one reviews

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