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BLACET RESEARCH MODEL EG3870
User & Assembly Manual
Blacet Research 94502 Stock Drive Lane, Lakeview, OR [email protected] http://www.blacet.com 541-947-5330
Contents Copyright. Reproduction by any means including the Internet prohibited without permission.
This document contains proprietary and trade secret information of Blacet Research and is providedas a service to the module owner. Any unauthorized duplication or transferral may violate trade secret laws.
Contents subject to change without notice.
Time Event ModulatorVC DADSR
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IntroductionThe Blacet EG3870 Time Event Modulator is a CV controlled DADSR with attenuverter CV inputs to allow a flexible combination of internal or external signals to dynamically control the ADSR segments. The Delay section allows 0 to 10 seconds of delay before the envelope starts.A wide variety of outputs include Full and Inverted envelopes as well as an attenuated envelope. Two pulse signals, EOA and HPP can be used to trigger external modules such as the Blacet EG2070 in AD mode or the DAD2970. The EOR gate output can also be used to control external modules.
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Operation NotesThe EG3870 uses the inverted envelope as the default cv source for modulation. Since this is occurring at the same rate as the regular envelope, the effect will be to bias each ADSR segment from the standard RC curve to one that is more linear or even bent the opposite direction. The following show the attack segment with no modulation in the center. FCCW modulation on the left and FCW on the right.
Using the Global CV Input, for example with the velocity, aftertouch or modulation wheel of a keyboard via the MIDIverter, allows flexible expression possibilities. Plugging into the separate ADSR CV Inputs will allow even more complex modulation.
Any external modulation source can be used here; find your favorites.
Delay function:The range of 0-10 seconds is spaced non-linearily around the dial with the rotation center equal to 1 S. The Delay IC will respond to the second gate after power up, so give your keyboard an extra tap after turning it on.The time delay is resettable, meaning that the interval will start over every time the gate is activated as long as the delay has not elapsed.There are two responses of the Delay, depending on if the gate is held active momentarily or throughout the delay period. In the first case, the delay will proceed automatically, then trigger the AD cycle, ending at the Sustain Level.This will be held until the next Gate is applied and held as in case 2. Setting the Sustain level at 0 will give an AD style envelope. In the second case, the envelope will proceed normally through the ADS cycle, releasing when the gate goes low.
End of Attack (EOA) is a 10 mS pulse with it’s rising edge at the end of the attack segment.
Half Power Point (HPP) is a 10 mS pulse with it’s rising edge occurring where the falling envelope passes the 5V (half power) point. It is similar to end of decay but offers somewhat more flexibility. For example it can occur during the decay segment or release segment.
End of Release (EOR) is a gate that goes low whenever the envelope ends.
Gate and Trigger Inputs: Only the Gate is actually needed. If a Trigger is input and the Gate is high, then the AD portion of the envelope will occur. Otherwise the envelope will rise to the Sustain Level only. The example below uses the Synth Tech Morphing Dual LFO to provide both the gate and trigger, with a variable phase lock. Thus the AD portion can be moved anywhere along the sustain “base”.
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Circuit DescriptionSchematic Sheet 2 shows the CV input section which consists of a buffer, U1c and an attenuator pot R1. An external Global CV is input here. Or, with no external signal the Inverted Envelope is normalled to the jack switch. This Global CV is normalled to the four cvs controlling Attack, Decay, Sustain and Release. An external cv input overrides any of these.A center-off phase shifting circuit (attenuverter) consisting of R2 thru R5 can be used to invert or not invert the cv into each of the four sections of the ADSR. The voltage at the IC is 0 to -5V for the AD and R. Sustain is 0 to +5V which explains the extra op amp U3c and scaling resistors for the Sustain processing section.Four trimpots, RT-1 thru RT-4 null out any non linearities in the four attenuverter pots so that the center detent is actually 0V. Pots R7 thru R10 are the manual setting pots on the right portion of the front panel. Thus the two sources of cv are mixed for each ADSR section.Schematic Sheet 1 shows the main section of the DADSR. CVs from sheet 2 are seen entering from the upper left before being scaled for the exponential control transistors on U6, AS3310 This is a version of the famous CEM3310 IC that was used extensively in synths from the 1980s thru 1990s. Three timing caps are connected to Pin 1 to allow different envelope ranges.The “Delay” in DADSR is covered by DAD U8 which is also used in the Blacet DAD envelope module. A variable time delay of 0-10S is initiated by the Gate input. A pulse circuit consisting of two sections of NOR gate U7 resets the delay when the Gate is removed. When the Delay time has run out, the Attack Enable pin goes high and turns on the AS3310 to complete the ADSR cycle. It is also normalled to the Trig pin which can be used separately.Outputs and LEDs are along the right side of the schematic. The EOA is generated on the 3310 and appears at pin 16. Because of the low, wide tolerance signal (-0.4 to -1.2V), op amp U9b is set at a gain of 27. U7 follows as a pulse generator that outputs a 10 mS pulse and activates LED2.EOR is simply the envelope output inverted by comparator U5a which is set to 50 mV by R33 and R34.The output level LED1 is driven by a voltage to current converter (U5d) which gives a more accurate visual display. D1 is a shottky diode which clamps any negative excursions of all the envelopes to about -0.2V.R11 Output Level and non inverting op amp U12c multiply the 5V nominal envelope to 10V. In a similar manner, U5c gives us a full envelope out.U12a and U12b form a mixer inverter that uses a 10V reference to provide an Inverted Out between 10V to common.The Env and Inv Env from the two preceding stages are used by comparator U12d along with pulse generator U13 to give us the HPP out and LED.Along the left side of the schematic, regulator U12 provides -5V for U6 which cannot tolerate -15V.U11 provides +5V to run U8, U7 and U13.U10 and U9a provide a 10V reference voltage.Toward the bottom of the schematic is the JPWR input power input strip with polyfuses, anti reversal protection and filtering for the +/- 15V supplies.
Kit Assembly Procedures:As this is a fairly complex kit, we advise assembly in at least a couple sessions or more.
• Caution! All front panel components are PCB mounted and must be aligned precisely if you ever hope to get the front panel mounted. Be sure to follow the advice presented when mounting these components! When checking alignment, close one eye. This will make your visual field 2D instead of 3D, which makes it easier to see alignment problems.
• Caution! Use protective eyewear during assembly, especially during soldering and lead clipping operations.• Caution! Solder contains lead, a toxic metal that can build up in the body if ingested. Be sure to wash your
hands after handling solder and avoid eating or touching your face while using it. (Lead traces left on your face or hands may find their way into your mouth and this is the most common way lead enters the body.)
• The key piece of advice is to take your time, be sure you put the correct part in each location, and solder it correctly. Read thru this manual and check your parts against the Parts List before starting!
• Because this is a double sided board, removing parts will be more difficult than with a single sided board since
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solder flows through the plated through holes. The usual method for replacing a part on a double sided board involves cutting all the legs of the component and desoldering the pins one at a time, using a solder sucker. This minimizes possible board damage due to excess heat. Needless to say, since you will be destroying the component, you want to get things right before you solder!
• If you make a mistake or are missing a part and need a replacement component, please e-mail us. Include your order invoice number and name.
• If you have not soldered a double sided board before, be aware that solder will flow through the plated board holes and out onto the opposite pad. Use only as much solder as required to make the connection look good on both sides of the board. A little care now will insure a long lasting reliable module.
• Do your assembly work on a soft towel or a few layers of paper towel. This will protect components from impact and make picking up small parts easier. Be careful when opening part bags (use scissors) as small parts can fly off a considerable distance!
Tools• You will need a 15 to 25 watt soldering iron with a fine pointed tip. • There are several choices for solder. ACID CORE SOLDER IS NOT ONE OF THEM! Use a standard fine gauge
(.031) rosin core, aqueous core, or a “no clean” type. We very highly recommend Kester 331 as this can be cleaned up with warm water and solders very nicely. Connections off the board or to the board that are inconvenient to clean may best be made with a “no clean” solder such as Kester 245. Rosin core solder can be used but is really somewhat old fashioned and flux removal can involve harmful chemicals. We build our boards with the 331 and 245 products and cannot guarantee results with rosin core solders.
• You will also need a lead bender, needle nose pliers, side cutters, and a nut driver set or pliers. A DMM will be necessary for checking voltages.
Inserting PartsTake a look at the PCBs. All the parts are mounted on the silkscreened side of the board. Be sure to follow directions. Use the “ref des” column on the Parts List to locate components. (The Type and Value fields will often have the part marking in “xx”.)We advise inserting components in groups according to type, checking them and then soldering the group. This will help avoid errors. Solder one leg of components first, then come back and do the other leg later. This practice avoids disturbing the solder joint on the first pin as it is setting up. Some items are heat sensitive and will benefit from this practice.PCB AssemblyYou can assemble the complete board matrix or snap apart the sections, which is a bit easier. After separating the boards and removing the tabs, take a small file to even out the area where the tabs were. This should only require a pass or two and is only necessary where the board will rest against the front panel.331 type solder should be used for these operations.Resistors:
• Insert all the resistors, bending the legs at 30 degrees. Check the values. Did you have any left over? Then solder in place. The resistor can be inserted in either direction, although a good practice is to orient the color code so that it can be read from left to right along with the PCB silkscreen. This simplifies checking the values and later troubleshooting/repairs. Don’t get confused over similar color codes.
• The color code chart shows how to identify resistor values. The exact hue of the colors can vary a bit, so be sure that you pick the right value. Using the parts list and putting the resistors into groups of the same value can help clear up any confusion. The suffix “K” is used to denote thousand and “M” stands for million. A 56K resistor is thus 56,000 ohms. The 1% resistors are blue in color and have 5 color bands, with the right one always being brown, indicating “1” % tolerance. The rest of the color bands are read in the same fashion as the 5% resistors with there being one more digit to consider. For example, a 75K 1% resistor reads from left to right: violet (7), green (5), black (0), red (2 zeros) or 75000. A possible problem with this system comes when the first digit is 1 (brown). Since the tolerance is also brown, make sure that you don’t read the resistor the wrong way!
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Tolerance (gold = 5%, brown = 1%)Multiplier (# of 0ʼs)
2nd digit1st digit
Resistor Color Codes
Black = 0Brown = 1Red = 2Orange = 3Yellow = 4Green = 5Blue = 6Violet = 7Gray = 8White = 9
3rd digit (only on 1% resistors)
For example: green (5), blue (6), orange (3 zeros), gold (5%)= a 56000 or 56K ohm, 5% tolerance resistor.
For example: violet (7), green (5), black (0), red (2 zeros), brown (1%)= a 75000 or 75K ohm, 1% resistor.
Diodes: Insert and solder the diodes: Note the orientation.PCB SymbolDiode
Resistor Networks: Observe the orientation. There will be a dot on the PCB and one on the network.IC Sockets: These will have a keyway or dot (pin 1) to indicate the correct orientation. Insert the socket and bend one leg at two opposing corners 45 degrees or so. Solder these two pins and check to see that the socket is flush with the board. Then solder all the pins. Jacks: Load the 13 jacks into the PCBs. Since these will have to go through the front panel later, precise mounting is a must. Carefully insert all jacks and flip each board over.
• Tip: Keeping the jacks in the board can be challenging but one useful trick is to bend the front pin forwards just a bit before inserting. Install the front pin first, pushing a bit forward to get the rear pins in place.
Solder only the front pin while applying a bit of pressure to the PCB in the vicinity of the jack. Do all the jacks and check the mounting before soldering any other pins. Close one eye and sight down the row of jacks. Each jack must be flush to the board and have no tilt from front to back. When everything looks perfect, solder the other pins.Capacitors: (Cap). There are several different types. You may need a magnifier to read the code on the small ceramics.
• Note that the electrolytic type must be properly oriented. Insert the side which has the longer lead closest to the “+” on the silkscreen. The opposite side of the capacitor should have a row of “-”.
Polyswitches: (PTC) PS1 and PS2. These have kinked legs and are located on either side of the power input jack.Power Input Jack: JPWR; note the orientation as shown by the silkscreen.Voltage Regulators: 78L05, 79L05 Reference Diode: LM4040AIZ-5.0 Transistors: 2N3904: These are all in T0-92 packages. Observe the correct orientation. Trim Pots RT1-RT4Test Points: Make loops with resistor trimmings and solder to each test point (TP1 thru TP4).Wash the PCB in warm water and rinse with distilled or deionized water. Allow to dry. Inspect all work very carefully.
*** Use 245 solder for the remaining assembly steps. ***Slide Switch: Install the slide switch on the -1 PCB
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Pots: Starting with the -2 PCB, Insert the four detent style pots (R2-R5) on the pcb (these have a notch at the center of the revolution) Note that R1 is not a detent style. Solder one mounting leg on each pot. Holding the PCB with one hand, remelt each solder joint and press the pot down onto the PCB. With one eye closed, sight down the row of pots making sure they are even and flat on the board. Solder the rest of the pot pins.Continue with the remaining pots with locations shown on the Parts List. Angle Brackets: Mount the two angle brackets to the top of the -1 PCB with a 4-40 screw going through the bottom of the board, through the unthreaded opening on the bracket and into a kep nut. Keeping the bracket to the back of the board, tighten securely. Check the alignment and adjust using a pair of pliers so that the bracket is square with the edge of the PCB.Mount the two brackets on the -4 PCB.Push Button Switch: Mount this switch on the -3 PCB.Inspect each PCB very carefully for shorts, bad solder joints, etc.Mounting small -5 PCB to the top of -2 PCB: Use the threaded spacer with a 4-40 x 1/4” screw and kep nut. Place a 3 pin section of the straight header between the two boards. The screw goes through the bottom of the -2 PCB and into the spacer. The nut attaches to the threaded end of the spacer after it passes through the -5 PCB. Align carefully, tighten the screw and nut. Solder the header pins.LEDs: Temporarily mount the -3 and -4 PCBs to the front panel. Position the four LEDs so that they line up with the front panel holes. They all go into the top of the two PCBs, with the longest leg next to the triangular PCB marking. Solder.ICs: Use a static free work station or wrist strap when installing the ICs. Observe correct orientation.Install the ICs now as they will be less accessible once the PCBs are mounted to the front panel. Make sure all the legs are straight and are actually going into the socket before seating the IC. Front Panel:
• Work on a soft towel to avoid damage to the front panel.Start by mounting the small -1 board to the front panel. Make sure the slide switch operates properly.Insert 3, 5 pin sections of straight header into H1, H2, H3 through the bottom of the -2 PCB. Attach the -2 PCB to the front panel with flat washers and hex nuts. Drop the headers through the -1 PCB. When everything looks good, solder the three headers and trim.Calibration of RT1-RT4: Connect a voltage source such as +15V (right hand vertical buss to the left of the power connector) to J1. Power up the module. Set pot R1 to mid range and R2-R5 mid range at the detent. Measure the voltage at each Test Point (TP1-TP4) and adjust each trimmer (RT1-RT4) for 0V.Installing Ribbon cables:Use scissors to cut three sections from the ribbon cables: 6, 11, and 10. Fold as shown. Take the 6 and 11 position cables and remove the cut insulation from each end. Insert in the -2 PCB with the bend toward the front panel and solder. Insert the 10 position cable toward the top of the -3 PCB with the fold facing the rear of the module. and solder.
Feed the two cables from the -2 PCB into the bottom of the -3 PCB and solder. Mount the -3 PCB to the front panel.Feed the remaining cable into the top of the -4 PCB and solder. (The PCB will be flipped over so that the component side faces the -3 PCB.) Mount the -4 PCB to the front panel.Press on the 11 knobs. The smaller knobs go to the left.
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TestingConnect a +/-15 V bipolar regulated power supply (such as the PS505 or PS800) to the board. Make sure that the connector is properly positioned on the header. Do not make the power connection to the board with the power supply turned on. These measures will help avoid damage to the unit! Use your DMM to monitor the +15V supply, using the left side of diode near the top of the power connector for common and the right side for +15V.Apply power. If your DMM does not indicate 15V or so, remove the power.If +15 is present, check the -15 at the right side of the bottom diode under the power connector. Check the ICs carefully to see if any are hot (they should not be). Are there any funny smells? If anything seems amiss, remove the power.CalibrationNo further calibration is necessary.
Troubleshooting, Repair, Warranty Most problems are caused by assembly errors. Don’t panic! Take a break, then check solder joints for good connection (no “cold” joints?), check for a blob of solder causing a short, check all component locations and polarities, and check for the possibility of a broken trace or a hairline short caused by under etching of the PCB, especially around the pots.If you encounter problems that you can’t solve, contact us, preferably via e-mail with a description of the problem. Let us know what does and does not work. We can then help you get your module working. We can also fix modules mailed to us for a minimum fee of $29 (if not covered by warranty). Contact us for an RMA before shipping.The parts contained in this unit have been carefully selected and tested. They are guaranteed for one year from the date of purchase. If you believe that you have a defective part (or if you have a part missing), contact us so we can provide you with a replacement or repair. Include your name and invoice number.Store your Manual in a secure location and never, ever throw it away! It is the best information available for your revision of this module. Manuals must be transferred to the new owner anytime you sell a module.We reserve the right to void the warranty or refuse to service any module that has been built with parts not supplied by us, modified in any way, subjected to abuse, or damaged beyond repair. Assembly Documents
• Parts list • Schematic • PCB drawing
