electronically reprinted from december 2010 peachtree · 2011-11-29 · amplifier with built-in d/a...

www.Stereophile.com, December 2010

DESCRIPTION Solid-state integrated amplifier with built-in D/A converter, USB interface, and digital iPod dock. Inputs: 1 line-level analog, 2 S/PDIF digital (1 coax, 1 optical). D/A signal/noise ratio: 118dB. Preamp output impedance: <30 ohms. Amplifier output power: 40Wpc into 6 ohms (14.8dBW) at <1.0 % distortion.DIMENSIONS 14.75" (380mm) W by 5" (130mm) H by 14" (360mm) D. Weight: 23 lbs (10.5kg).SERIAL NUMBER OF UNIT REVIEWED 0004184, firmware v1.1.PRICE $999. Approximate number of dealers: 104.MANUFACTURER Signal Path International, 2045 120th Avenue NE, Bellevue, WA 98005. Tel: (704) 391-9337. Web: www.signalpathint.com.

ART DUDLEY

PeachtreeiDeccoD/A INTEGRATED AMPLIFIER

As with so many other things, from cell phones to soy milk, the idea of a portable MP3 player was something I at first disdained, only to later embrace with the fervor of any reformed sinner. But not so the idea of a high-fidelity iPod dock: Given that I now carry around several hundred high-resolution AIFF files on my own Apple iPod Touch, the usefulness of a compatible transport seemed obvious from the start. Look at it this way: In 1970, whenever I bought a

music recording, I could enjoy it on any player, in any room in the house. In 2010, why shouldn’t I enjoy at least that degree of convenience and flexibility—without resorting to a pair of tinny, uncomfortable earbuds?

So it was that Wadia Digital’s first iPod dock, the Model 170, earned its status as a seminal product; and so, I daresay, will Peachtree Audio be recognized for pioneer-ing yet another worthy genre with their iDecco: a perfectionist-quality iPod dock and a similarly pedigreed digital-to-analog converter, combined with a tube-buffered preamplifier and a 40Wpc power amplifier—all for $999.

DescriptionThe US-designed iDecco, which is manufactured in mainland China, has its origins in the Peachtree Nova ($1199), a similar DAC-integrated with a little more power (80Wpc) and a lot less dock. Having earned dozens of rave reviews, including John Marks’ writeup in “The Fifth Element” in the August 2009 Stereophile, and with re-tail sales nearing the 4000 mark, the Nova endures. But Peachtree’s David Solomon

Peachtree iDecco D/A integrated amplifier with digital iPod dock

ElEctronically rEPrintED FroM DEcEMbEr 2010

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

P E A C h T R E E I D E C C O

now seems ready to bring the gospel of good sound even nearer to the audio-indifferent.

Solomon describes the genesis of the iDecco: “We simply started read-ing RIAA statistics, and there it was: Look what’s happening! Consumers have changed the way they buy music, and [the world of downloadable media files] is where they are.”

The Peachtree iDecco is designed around a traditional linear power sup-ply with a toroidal transformer: Thank-fully, wall warts are neither required nor supplied. (I’ll probably never ac-cept the idea of four-figure domestic audio products that use the same sort of AC adapter as a Hello Kitty portable CD player.) For its part, the power amp

is built around the TDA 7293 power MOSFET IC from ST Microelectron-ics, operated in class-A/B. The pream-plifier’s solid-state gain stages run in class-A, while some degree of driver-

stage buffering is conferred by a 6N1P dual-triode tube. As in the Peachtree Nova, the tube buffer can be switched in and out via a pushbutton on the re-mote handset, a function not duplicated

T o perform the measurements on the Peachtree iDecco, I mostly used Stereophile’s loan sample of the top-of-the-line Audio Precision SYS2722 system (see the January 2008 “As We See It”

and www.ap.com); for some tests, I also used my vintage Audio Precision System One Dual Domain and the Miller Audio Research Jitter Analyzer.

Before I did any testing of the iDecco, I ran it at one-third power into 8 ohms for an hour, which imposes the maximum heat stress on an amplifier with a class-AB output stage. At the end of that time, the iDecco was hot but not bothered.

Looking first at the iDecco’s performance as a digital decoder, a full-scale 1kHz tone clipped the amplifier’s out-put stage with the volume control set to 2:30. The level from the variable preamp outputs with the tube in-circuit was 848mV in this condition. The maximum level from the line-level output jacks was 2.06V, sourced from a low impedance of 10 ohms, and while both the loudspeaker outputs and the fixed-level line outs preserved absolute polarity for digital sources, the variable preamp outputs inverted polarity with the tube. Other than when noted,

I continued the digital testing from the fixed line-level outputs with the volume control set to its minimum, to avoid stressing the iDecco’s amplifier output stage.

The iDecco locked to S/PDIF datastreams with sample rates ranging from 32 to 96kHz, but not to data with sample rates greater than 96kHz. The top two pairs of traces in fig.1 show the iDecco’s D/A frequency response with 44.1kHz data (cyan, magenta traces) and 96kHz data (blue, red) with the rear-panel Filter pushbutton set to Fast. The response is flat and extended at both frequency extremes, at least until the inevitable steep rolloff just below half the sample rate. By contrast, the green and gray traces in fig.1 show the response with 44.1kHz taken from the variable preamp outputs with the tube operating, the volume control set to 2:00 and the Filter set to Slow, offset by 1dB for clarity. There is now a slight (0.3dB) imbalance between the channels and the low-frequency response is down 3dB at 11Hz. At the other end of the spectrum, the effect of the Slow filter is to roll off the top-octave output a little early, the response being down 3dB at 19.5kHz.

Testing the DAC’s resolution with a swept bandpass filter while it decoded a dithered 1kHz tone at –90dBFS gave

M E A S U R E M E N TS

Fig.2 Peachtree iDecco, 1⁄3-octave spectrum with noise and spuriae of dithered 1kHz tone at –90dBFS with 16-bit data (top) and 24-bit data (bottom). (Right channel dashed.)

Fig.1 Peachtree iDecco, frequency response at –12dBFS into 100k ohms from fixed outputs with data sampled at 44.1kHz (left channel cyan, right magenta) and 96kHz (left blue, right red), and from variable outputs with volume control set to 2:00 (left green, right gray). (1dB/vertical div.)

The iDecco’s tube can be switched in and out of circuit with the remote.



on the iDecco’s front panel; given that the tube is “ramped in” to the circuit—with full rail voltage on the plates at all times—the changeover takes only a few seconds. Solomon says that, with the tube switched in, “we lose about 6dB of signal/noise ratio. But I think it sounds better.”

The D/A board is where things get really interesting. The star of the show is an ES9006 Sabre DAC from ESS Technology, of Fremont, California. According to Solomon, the Sabre DAC reclocks the datastreams from all digi-tal sources, and upsamples them to 24 bits and 96kHz. Solomon also says that the iDecco’s D/A board incorporates 11 regulated power supplies of its own, to enhance interstage isolation and thus

keep noise to a minimum.The iDecco’s USB transceiver is

separate from the ESS Sabre DAC, and is galvanically isolated from the rest of

the board. “We learned early on we had to do something about noise coming off the USB cable,” Solomon says. The USB socket and the iPod connection—the latter is purely digital, and bypasses the player’s headphone output—are also transformer-coupled to the circuit, to

prevent grounding glitches and switch-ing noise.

The iDecco’s front panel is simple and spare: That lucky tube gets its own

little window, flanked on one side by a (motorized) volume knob, and on the other by five illuminated source-selec-tion buttons. All front-panel controls are duplicated on the pleasantly rub-bery remote-control handset, alongside such extras as a Mute button and the

the traces shown in fig.2. The top pair of traces were taken at the variable preamp jacks, again set to 2:00, with 16-bit data, and the bottom pair with 24-bit data; you can see that the increase in bit depth drops the noise floor by 10dB or so in the treble. There is a slight bump at the 60Hz AC line frequency, but this is sufficiently far down in level not to be an issue. Repeating the analysis, this time from the fixed-level jacks with an FFT technique, gave the traces shown in fig.3. The increase in bit depth now drops the noise floor by 18dB, which implies that the iDecco’s ESS 9600 Sabre chip has at least 19-bit resolution. However, some harmonics of the AC frequency can be seen with the 24-bit data (blue, red traces), and a regular series of distortion harmonics is also unmasked by the lowering of the noise floor. DAC linear-ity error with 16-bit data (not shown) was vanishingly low to below –100dBFS, and the iDecco’s noise floor was low enough to allow the three DC voltage levels that describe an undithered 16-bit tone at –90.31dBFS to be readily resolved (fig.4). With undithered 24-bit data, the result was a noisy but otherwise well-defined sinewave (not shown).

When it came to distortion, the two line-level outputs varied dramatically. The blue and red traces in fig.5 show the

spectrum of a full-scale 50Hz tone at the fixed-output jacks. The second harmonic lies at –90dB (0.003%), the third at –80dB (0.01%), and the fourth at –110dB (0.0003%). By contrast, while the third harmonic remains at the same level from the tubed variable-output jacks, the fourth harmonic has risen to –90dB and, more significant, the second has

Fig.3 Peachtree iDecco, FFT-derived spectrum with noise and spuriae of dithered 1kHz tone at –90dBFS with: 16-bit data (left channel cyan, right magenta), 24-bit data (left blue, right red).

Fig.5 Peachtree iDecco, spectrum of 50Hz sinewave, DC–10kHz, at 0dBFS into 100k ohms from fixed outputs (left channel blue, right red), and from variable outputs with volume control set to 2:00 (left channel cyan, right magenta). (Linear frequency scale.)

Fig.4 Peachtree iDecco, waveform of undithered 1kHz sinewave at –90.31dBFS, 16-bit data (left channel blue, right red).

ThE TubE buFFER cAN bE SWITChED IN AND OUT VIA A PUShBUTTON oN ThE REMoTE hANDsET.

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



aforementioned tube switcher. Addi-tional buttons on the handset can be used to control the most basic playback functions of the iPod itself: skipping forward or backward through various songs (but not albums), pausing the music, and resuming play.

The rear panel is nicely laid out, with inputs for four of the five sources—USB digital, coax and optical S/PDIF digi-tal, and line-level analog—plus one pair of preamp outputs for subwoofers or other ancillaries, and a pair of line-level outputs for those who might wish to use the iDecco as a standalone DAC to drive some other preamp or amp. Two other items deserve mention: a two-position switch for choosing between soft and steep digital filter slopes, and

a Jitter Bandwidth control, with Nar-row and Wide settings (think of them as fine and coarse sieves, respectively), for use with the S/PDIF inputs.

Finally, the Peachtree iDecco is pro-

tected by an MDF “wrap” liberally vented for heat dissipation, and finished with a sufficiently glossy (black) paint that I long assumed the case was made of some sort of polymer.

risen to –50dB (0.3%). In both cases, a picket fence of very-low-level spuriae is also visible. The primary difference between the two outputs is that, with the variable jacks, the signal passes through a 6922 tube. It is the “bent” transfer function of this tube that generates the even-order distortion.

As can be seen in fig.1, the slow in “Slow Filter” refers to the rate of the reconstruction filter’s ultrasonic rolloff. It is generally felt that a slower rate of rolloff sounds better, but the downside is that there is less rejection of the ultrasonic images that result from the digitizing of the signal. This can be seen in fig.6, which shows the spectrum of the iDecco’s fixed outputs while it decoded 24-bit data representing an equal mix of high-level 19 and 20kHz tones. The primary ultrasonic image of the two tones is suppressed by just 12dB, and other aliasing spuriae are folded down into the audioband. Switch-ing this filter to Fast gives the spectrum shown in fig.7: the ultrasonic images have dropped significantly in level, as have the audioband aliasing spuriae. The primary intermodulation product, at 1kHz, has risen slightly, to –96dB (0.0015%), but this is still negligible in absolute terms.

The iDecco offers three choices of digital input: S/PDIF (on coaxial and TosLink connectors), USB, and from an iPod plugged into the top-panel dock; a second rear-panel pushbutton selects between Wide and Narrow receiver PLL bandwidths. The Wide setting is to allow the iDecco to suc-cessfully lock to digital sources with poor-tolerance clocks; however, the downside is that this gives rise to increased

Fig.7 Peachtree iDecco, HF intermodulation spectrum, Fast Filter, DC–24kHz, 19+20kHz at 0dBFS into 100k ohms (linear frequency scale).

Fig.6 Peachtree iDecco, HF intermodulation spectrum, Slow Filter, DC–24kHz, 19+20kHz at 0dBFS into 100k ohms (linear frequency scale).

Fig.8 Peachtree iDecco, Wide receiver, high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz, 16-bit data from SYS2722 via 15’ TosLink. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz (left channel blue, right red).


USB and S/PDIF digital inputs—and one pair of analog inputs.



Setup and useLike the Naim Uniti CD/receiver be-fore it (see my review in the March 2010 Stereophile), the Peachtree iDecco led a nomadic existence in my home: I applied it to four different pairs of loudspeakers (Audio Note AN-E/SPe H/E, Wilson Audio Sophia 3, Quad ESL, Advent Loudspeaker) in three different rooms. Most of my listening was done with the first two pairs, in my listening room/of-fice (19' long by 12' wide by 8' high).

Installation was a breeze: Once I’d connected the iDecco’s USB input to my Apple iMac G5 computer (OSX 10.6.2), a sound output device listed as “USB Audio DAC” appeared in the computer’s System Preferences win-dow, and I duly selected it. As for its

top-mounted iPod connection, the iDecco is supplied with four different dock inserts, one of which fit my and my daughter Julia’s iPod Touches to a T.

In addition to AIFF and MP3 files from our iPods (v.4.0.2), and those plus WAV files streamed from my com-puter’s copy of iTunes (v.9.2.1), I tried bypassing the iDecco’s USB transceiver by streaming files to a Stello U2 USB transceiver, then on to the iDecco’s co-axial S/PDIF input by means of a Black Cat Veloce cable (a superb product at a bargain price of $123). I compared the whole of the iDecco’s USB DAC system to various outboard USB DACs on hand, using the latter to address the Peachtree’s single pair of line-level ana-log inputs (labeled Aux). I also tried my

aging Sony SCD-777ES SACD/CD player, from both its line-level analog outputs and its optical S/PDIF output. I had intended to try streaming music files direct to the iDecco’s optical input, from the iMac’s headphone jack—which, remarkably, is also an S/PDIF digital output—but an optical plug adapter that I ordered for that purpose didn’t arrive in time. A Follow-Up may follow.

ListeningIt’s often presumed that, all other things being equal, the performance of an inte-grated amp is compromised compared to the performance potential of good separates. Take that equality from the scene and the compromise is presumed greater still, as with an especially cheap

levels of jitter. Fig.8, for example, shows the spectrum with the 16-bit J-Test signal fed to the iDecco via TosLink. Though data-related jitter other than the sidebands at ±229Hz is at the residual level, there are strong sidebands at ±1.8kHz, and a significant widening of the central spectral peak due to random low-frequency clock variations. The jitter level was 519 picoseconds peak–peak, according to the Miller Analyzer. This is still low in absolute terms, but switching to the Narrow setting lowered the jitter level to below 200ps, narrowed the central peak in the spectrum, eliminated the high-frequency sidebands, and reduced all data-related sidebands to the residual level of the test signal (fig.9), which is superb performance.

The iDecco takes data from an iPod in digital format; repeating the jitter test with the 16-bit J-Test signal play-ing on an iPod Classic 160GB gave a low 310ps of jitter. While there were no data-related sidebands present in the spectrum (not shown), there were sidebands of unknown origin present at ±91 and ±816Hz. Feeding USB data from my MacBook gave just 260ps of jitter, from sidebands at ±1423Hz (not shown). The iDecco offers excellent rejection of jitter, though with both iPod and USB sources

there was significant widening of the central spectral peak, again due to the presence of random low-frequency jitter. Examining the iDecco with the Mac’s USB Prober utility identified the USB receiver as a “USB Audio DAC” from “Burr Brown from TI” operating in adaptive isochronous mode, and indicated that it accepted 16-bit data with sample rates of 32, 44.1, and 48kHz only.

Moving on to the iDecco’s amplification section, the output from the speaker jacks preserved polarity (ie, was non-inverting) for digital inputs, but inverted absolute polarity for analog signals fed to the Aux input via the tube. The maximum gain for analog input signals was fairly low for an integrated amplifier, at 28.7dB into 8 ohms. The Aux input impedance was usefully high, at 48k ohms at low and middle frequencies, dropping slightly but inconse-quentially to 42k ohms at the top of the audioband.

I had to scratch my head a bit when I examined the iDecco’s output impedance. I perform this measurement by comparing the output voltage with the amplifier driving 8 or 4 ohms with how much that voltage rises when I remove the load. A simple Ohm’s Law calculation then gives me the amplifier’s output impedance (including the cables in use,

Fig.9 Peachtree iDecco, Narrow receiver, high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz, 16-bit data from iPod Classic. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz (left channel blue, right red).

Fig.10 Peachtree iDecco, frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), 2 ohms (green). (1dB/vertical div.)





integrated amp. For the amp to share its chassis and power supply with source components—an iPod dock and a D/A converter, perhaps?—harshens the com-promise still further. So the question becomes: How cleverly were those compromises chosen and implemented?

In the context of the perfectionist-quality gear with which I’m familiar, the iDecco’s shortcomings were far from severe, and had more to do with abstract sonics than purely musical ca-pabilities, the latter being extremely good (a subject to which I’ll return in a moment). The iDecco’s overall sound was nonetheless satisfying, with a treble range that sounded naturally extended, lacking both the excess grit and the pe-culiarly chalky quality that characterizes

a great deal of budget solid-state play-back gear. The opposite end of the spec-trum was also well served: The lowest piano notes and drum and synth tones

sounded fast and well controlled, albeit without quite the locomotive weight one can hear from, say, a Shindo, Lamm, Audio Note, or EAR tube amp. But the Peachtree did a satisfying job with the huge orchestral drum sounds and other harrowing effects in John Adams’ On the

Transmigration of Souls, with Lorin Maa-zel leading the New York Philharmonic (CD, Nonesuch 79816-2).

Actually, the iDecco’s most identifi-

able shortcoming was that to which I find myself least sensitive: It didn’t have quite the same degree of spatial depth as the best contemporary electronics. I might also add that my favorite elec-tronics, all of which are either very ex-pensive, or very rare and thus terrifyingly

of course). However, when I disconnected the load with the iDecco, the output voltage dropped, suggesting that the Peachtree actually has a negative output impedance of about –0.2 ohm. This can be seen in the plot of the ampli-fier’s frequency response (fig.10), where the output with the 2 ohm load (green trace) is higher than it is with 4 or 8 ohms. This is unusual, and suggests that the amplifier circuit uses a degree of positive feedback. However, the variation in response with our simulated speaker (gray) is very low.

Note the low-frequency rolloff in fig.1, which, at –3dB at 55Hz, is even more extreme than that seen in the response from the preamp outputs (fig.1, green and gray traces). I was puzzled by this, but after some thought I repeated the response measurements at various settings of the volume control. The traces in fig.10, taken with the volume control at its maximum, are repeated as the bot-tom pair of traces in fig.11. The other traces in this graph were taken at progressively lower settings of the volume control, and you can see that the iDecco’s low frequencies are well extended at volume-control settings of 12:00 and below. It looks as if the iDecco reduces its low-frequency bandwidth as you increase the volume beyond 12:00, and that this is performed in the tubed preamp section.

Fig.10 indicates that the iDecco’s ultrasonic response extends well beyond the 200kHz limit of this graph. This correlates with very short risetimes on its response to a 10kHz squarewave, but there is a small degree of overshoot with very-high-frequency ringing into lower impedances (fig.12). Channel separation was good rather than great, at 87dB R–L and 59dB L–R at 1kHz, as was the wideband, unweighted signal/noise ratio (taken with

Fig.12 Peachtree iDecco, small-signal 10kHz squarewave into 4 ohms.

Fig.13 Peachtree iDecco, distortion (%) vs 1kHz continuous output power into (from bottom to top at 1W): 8, 4 ohms.


Fig.11 Peachtree iDecco, frequency response at 2.83V into 8 ohms with volume control set to (from right to left): maximum, 3:00, 2:00, 12:00, 9:00 (left channel blue, right red, 1dB/vertical div.).

ThE iDECCO’S OVERALL SOUND WAS NONEThELESS SATISFyINg, wITh A TREbLE RANGE ThAT souNDED NATuRALLy ExTENDED.



expensive, imbue recorded music with a little more presence, somewhat more color, and a lot more texture than did the iDecco. That would be true—but who in the world would expect otherwise?

As to the iDecco’s purely musical performance, I was impressed beyond all reasonable expectations. The iDecco played music with an excellent freedom from timing distortions: Upbeat fare such as the title track of Audra Mae’s The Happiest Lamb (CD, Sideonedum-my SD1416-2)—a more rhythmically nuanced track than average, I daresay—exhibited fine pacing. Even downtempo numbers—such as Peter Rowan and Tony Rice’s “Trespasses,” from the Quartet album (ripped from Rounder 11661-0579-2), and Procol Harum’s

poignant “An Old English Dream,” from The Well’s On Fire (CD, Eagle ER 20006-2)—maintained good momen-tum, and resisted tipping over like the musical equivalent of a ponderous bike: a rarity, believe it or not, among cheap and dear equipment alike.

Of course, of the many playback modes of which the iDecco is capa-ble, I most looked forward to hearing AIFF files from my iPod Touch played through the integral iPod dock, and comparing them with the exact same files streamed from my iMac-iTunes installation through the iDecco’s USB input. I spent many a long hour doing just that.

The results weren’t always what I ex-pected. The distinctions weren’t huge,

by any measure, and they confounded me further by being somewhat music-dependent. For the most part, I slightly preferred the iMac-to-USB route, for a number of reasons: That approach not only rewarded me with the most open, least opaque treble performance of which the iDecco seemed capable, but also with the Peachtree’s best sense of note-to-note flow—which was considerable. The beautiful, sun-dappled melodies that fill Elgar’s Nursery Suite, as performed by Paul Goodwin and the English Chamber Or-chestra (ripped from Harmonia Mundi HMU 907258), were easier to trace through the USB than through the iPod inputs. Likewise, the subtle keyboard wash in the background of Jeff Buckley’s “Lilac Wine,” from Grace (ripped from


the volume control at its maximum but the Aux input shorted) at 67.5dB ref. 1W into 8 ohms. This was primarily due to low-level spuriae at 120Hz and its harmonics that I couldn’t eliminate by experimenting with the grounding between the iDecco and the Audio Precision test system. A-weighting the S/N ratio, which discounts the effects of LF and HF noise, thus improved the result to 83dB.

Peachtree specifies the iDecco’s maximum output power as 40Wpc into 6 ohms (14.8dBW) rather than the usual 8 ohms. However, fig.13 shows that the amplifier didn’t clip (defined as 1% THD) until 40Wpc into 8 ohms (16dBW) and 53Wpc into 4 ohms (14.2dBW). The low-power distortion is around 0.03%, but increases in a linear fashion with increasing power, this due to the mainly second-harmonic distortion introduced by the preamplifier stage (figs. 14 and 15). Intermodulation distortion with an equal mix of high-frequency tones at a level just below visible clipping on the oscilloscope screen (fig.16) was primarily the low-order dif-ference product, at –50dB (0.3%), again this stemming from the tubed preamp stage; but the power-supply–related spur-iae can also be seen in this graph, admittedly at a low level.

Peachtree’s iDecco may be budget-priced, but it packs a lot of functionality into a small package. Its D/A section is

particularly impressive technically, especially regarding its resolution and rejection of jitter, but you need to take the output from the fixed line-level jacks to get the maximum performance from it. As an integrated amplifier, the iDecco’s performance is dominated by its tubed preamp section, which introduces even-order harmonic distortion much like that of a classic tubed amplifier. —John Atkinson

Fig.14 Peachtree iDecco, 1kHz waveform at 1W into 8 ohms (top), 0.155% THD+N; distortion and noise waveform with fundamental notched out (bottom, not to scale).

Fig.16 Peachtree iDecco, HF intermodulation spectrum, DC–24kHz, 19+20kHz at 20W peak into 8 ohms (linear frequency scale).

Fig.15 Peachtree iDecco, spectrum of 50Hz sinewave, DC–10kHz, at 20W into 8 ohms (left channel blue, right red; linear frequency scale).



Columbia CK 57528), seemed more delicate, and consequently more effec-tive, through the USB.

But played through the iDecco’s USB input, some music—soft acoustic fare, for the most part—could at times sound a bit too smooth for my tastes: listenable, but comparatively unstir-ring. On guitarist David Grier’s ap-proach to “Little Wing,” for example, from Phillips, Grier & Flinner’s Look-ing Back (ripped from Compass 7 4342 2), I found myself thinking that the sound from the iPod input gave a bet-ter feeling of (realistic) pick-on-string noises, while most of the outboard USB DACs I had on hand—especially the Wavelength Cosecant ($3500)—were even more satisfying. That said, I suspect that the iDecco’s ultrasmooth Sabre DAC would be more at home in budget systems, and with music files of less than high resolution.

A few words about the iDecco’s more esoteric user controls: Even though it sounded a little brighter and sharper, I generally preferred the iDecco’s Fast fil-ter slope, which seemed to get the most out of note attacks, natural textures, and the like. Also, as the iDecco’s very useful manual would lead one to expect, digi-tal sources that are presumed to be low in jitter were sonically better served by the Narrow setting of the jitter switch, whereby music sounded a little more substantial and detailed, and more musi-cally purposeful and tuneful. As for that tube switch, the differences were extraor-dinarily slight, but I did prefer having the tube in-line; voices and lead instruments then gained a shade more body and color. Without the tube, the sounds of solo voices were more like outlines: perimeters, with anchor points in the bass and treble, but missing some midrange fill.

NovaA final performance note: Just before writing this review, I compared the Peachtree iDecco with a well-worn sample of its predecessor, the Peachtree Nova. I expected few, if any, obvious differences, especially when driving the more sensitive speakers at my disposal—an expectation that was confounded, howsoever slightly. The smoothness that characterized the iDecco’s USB input was, if anything, more conspicu-ous through the Nova, in addition to which the latter presented a soundfield noticeably larger than that of the less expensive Peachtree amp. Through the iDecco, Bob Dylan’s Highway 61 Revis-

ited (ripped from the “Red Book” CD layer of Columbia CH 90324) sounded as I’ve come to expect over the course of several years: a little bright. (In the open-ing of “Queen Jane Approximately” in particular, the trebly electric guitar and hi-hat tambourine can be a bit much.) The Nova rounded off those high-frequency edges, and seemed to spread the left-channel piano and the right-channel organ farther away from each other—qualities that it imposed on a variety of other recordings, as well. The distinctions were sufficiently slight that the Nova review sample’s longer run-in period could well have been a factor; still, those whose rooms and speakers are more

kind to soft trebles, and whose needs don’t include an iPod dock, may wish to hold out for the higher-priced spread.

ConclusionsIn the August 2009 Stereophile, John Marks suggested that Peachtree Au-dio’s Nova is “the Dynaco Stereo 70 for the 21st century.” Well said—and if so, Peachtree’s iDecco is surely the latest incarnation of the Advent 300 receiver: great source, great styling, great sound.

The source part is obvious, the styl-ing subjective—and, I’m happy to say, the sound is wonderful. On the one hand, the iDecco is much closer than the aver-age affordable product to having what I consider true perfectionist-quality sound: very good bandwidth, openness, clarity, timbral neutrality, and smoothness, with spatial qualities that, if not quite top-drawer, are surely leagues above those from which the average Peachtree owner will have just upgraded. On the other hand, comparing the iDecco to my own system of Shindo tube electronics and vintage phono components—a larger in-vestment by a factor of 30 or so—is silly to the point of pointlessness: To para-phrase Voltaire, the better may indeed be the enemy of the good, but for the vast, hurtling majority of people, the iDecco is the better.

And even for this perfectionist, it’s quite good enough: During its time in my home, the Peachtree iDecco proved so delightful, so indispensable, that I had no choice but to buy it. A perfec-tionist-quality music system—just add speakers!—with a three-figure price? For the domestic audio market of 2010 and beyond, a more important new product is hard to imagine. nn

ASSOCIATED EQUIPMENTANALOg SOURCES Thorens TD-124 Mk.II turntable; EMT 997, Thomas Schick tonearms; Shindo SPU, EMT OFD 25 & OFD 65, Ortofon 90th Anniversary SPU cartridges.DIgITAL SOURCES Ayre Acoustics QB-9, Wavelength Audio Cosecant, HRT Music Streamer II & II+, Chord Gem USB DACs; Stello U2 USB transceiver; Apple iMac G5 computer running Apple iTunes; Sony SCD-777 SACD/CD player.PREAMPLIFICATION Auditorium 23 Hommage T1 step-up transformer; Shindo Masseto, Shindo Vosne-Romanee preamplifiers.POWER AMPLIFIERS Shindo Corton-Charlemagne & Lafon GM-70.LOUDSPEAKERS Audio Note AN-E/SPe HE, Wilson Audio Specialties Sophia 3, Quad ESL, Advent Loudspeaker.CABLES USB: Transparent Performance USB. Digital: Black Cat Veloce 75 ohm. Interconnect: Audio Note AN-vx, Shindo Silver. Speaker: Auditorium 23, DIY copper.ACCESSORIES Box Furniture Company D3S rack (source & amplification components); OMA slate plinth (Thorens turntable); Breyer horse (“Pandora”) as chassis damper (amplifiers); Keith Monks record-cleaning machine.—Art Dudley

When I first listened to the Peachtree iDecco—in my room, with my Advent Loudspeakers—

it was like finding the Holy Grail, or a 10,000-year-old Macedonian ballet shoe. It was awesome. The sound was much clearer than with head-phones. But this . . . there are no words for it: The iDecco had spirit. It almost echoed in my tiny little (no other words for it) black-hole-of-sound bedroom.

Even with the trickiest pieces of music—such as Strauss’s Die Fleder-maus, from the Twilight soundtrack, or the Cranberries’ “Linger”—the iDecco was perfect, accentuating underlying notes, or subtle crescen-dos and decrescendos.

And it’s not too steeply priced— bon appétit and happy shopping! —Julia Dudley

I N My R O O M

Posted with permission from the December 2010 issue of Stereophile ® www.stereophile.com. Copyright 2010 Source Interlink Media. All rights reserved.For more information about the use of this content, contact Wright’s Media at 877-652-5295

72766

www.wrightsmedia.com

electronically reprinted from december 2010 peachtree · 2011-11-29 · amplifier with built-in d/a...

Documents