eric g's 3P Modular

This is my self built modular synth. It is a three cabinet, MU, portable Moog look-alike. Most modules are designed and built by me but there are also modules from Arrick, Doepfer and SSL.

Module listing

Signal Sources:

8 VCO (CEM3340)
2 VCO (XR2206)
2 Hex oscillator (TR-808-like / Psyco LFO)
1 Noise generator (Lo, red, pink, white, blue and variable noise)
1 VC Digital noise generator
1 Percussion module (Noise gen., Envelope, VCA)
1 Music Thing Radio Music Built into an MU panel
1 SSL Scat Talker
1 FSFX 101 Macro Digital Oscillator
1 Krisp1 Oakley Slim VCO

Filters and other Signal Modifiers:

2 VCF - ADSR - VCA (SSM2044, SSM2056, BA6110. Ex. Bratigel Module)
2 Multimode VCF (CEM3320)
2 State variable VCF (Like SEM but with UAF42)
1 Twin peak VCF (Electro Harmonix EH400 dual peak LPF)
1 Fixed filter bank (like Moog 907)
1 VC Phase shifter (Roland Phase 2)
1 VC Comb filter (Korg Trident Flanger)
1 VC Wave Multiplier
1 Ring modulator incl. VC sine generator
1 VC Frequency shifter (Doepfer A-126 + A-143-9)
2 Dual VCA (CEM3330)
1 VC Analog delay (Ibanez AD-80)
1 VC Spring reverb
4 4-input mixer
6 4-input attenuators/mixer (half height, sort of like Moog CP3A)
1 PLL
1 Arrick Q130 Clipper/rectifier
1 Arrick Q108 Amplifier
1 Arrick Q111 Pan/Fade
1 SSL Segwencer

CV and Gate Sources and Modifiers:

2 Dual Modulation generator (LF or audio, MS-20 style)
2 VC ADSR (CEM3310)
2 Slope generator (AR/AD envelope/LFO or Gate delay/duration/inverter)
1 6-step Event generator
1 S/H inc. clock generator
1 Dual quantizer (Doepfer A-156)
1 Gate sequencer 4x8 + bar counter (half height)
1 Envelope follower, inc. preamp
1 Dual analog switch
1 Dual voltage processor
1 Triple gate/signal divider
1 Level decoder
7 CV/Gate bus (half height)
1 Joystick (half height)
3 Power panel (half height)
1 Arrick Q960 Sequencer
1 Arrick Q962 Sequential switch
1 Arrick Q109 Envelope Generator
1 SSL O'Tool oscilloscope etc.

Each half-size module has a row of multiples.

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Demo video of the sequencer cabinet.

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Schematics Comments

Unspecified potentiomenters are 22k - 100k LIN.
Unspecified diodes are 1N4148 or 1N914.
Capacitors have voltage tolerance that is higher than the supply voltage.
Unspecified transistors are not critical, take what you have.
All board-to-wire connectors are simple pin headers.
You may use the schematics freely as long as it is for non commercial use, but please cred eric g if you do.
Sorry, but I can't give support if you build any of this.

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Modules

OSCILLATOR CEM3340

This is a standard CEM3340 VCO. It has all the features that the chip offers.
A special feature is the Frequency knob, that acts as fine tuning if you select any footage,
but as a course control if you select LO or MAN.
Schematics

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DUAL OSCILLATOR CEM3340

This is a Dual CEM3340 VCO. It has the basic features that the chip offers.
It is designed to save panel space and be used in a typical dual-oscillator voice.
Special feature: The 5:th interval switch on the second oscillator.
Schematics

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OSCILLATOR XR2206

This is a XR2206 VCO. It is a basic design without an octave switch,
so mainly not intended for musical use. It tracks 1V/oct though.
It has a waveform converter for sawtooth, an Audio/LF switch and an AM input.
Schematics

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HEX OSCILLATOR

This is a hex schmitt-trigger inverter oscillator. It is based on the Roland TR-808 design.
One variant is for audio and outputs six squarewaves for eerie or noisy sounds.
The other one is for LF and outputs the sum of six square LFO:s for complex modulation patterns.
A CV (no scale) input is provided for all six oscillators.
Schematics

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NOISE GENERATOR

An ordinary analog noise generator, made from a zener diode. Various filters provide
the different colours. A variable colour is also available, using a Sallen-Key LPF.
Schematics

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DIGITAL NOISE GENERATOR

Voltage Controlled Digital Noise. Your usual shift register noise, under 1V/oct control.
Clock output for use in other modules, plus popcorn noise function.
Schematics

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PERCUSSION

A simple percussion module for creating the typical noise percussion sounds.
A zener diode white noise generator, a Sallen-Key LPF, a VCA and a simple EG.
EG out and ext. in for adding an oscillator, a sample or whatever.
Schematics

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SSM FILTER, EG AND AMP

An SSM2044 VCF, an SSM2056 ADSR and a Roland BA6110 VCA. This module is originally
from a Hohner Symphonie D98 organ (probably from a synth voice) and was refined by Bratigel
as a module. I have then converted it to a MU size panel, added some ins and outs
and added resonance volume compensation. Typically used as a compact voice
with the Dual Oscillator.
Schematics

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CEM MULTIMODE FILTER

A CEM3320 VC 4 pole Multimode Filter with lo, band or highpass function and VC resonance.
The filter has a halfway (12 dB/oct) output and resonance volume compensation.
Schematics

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STATE VARIABLE FILTER

This is a standard State Variable Filter, as found in SEM, Yamaha CS or Wasp synths.
This one is however based on the Burr-Brown UAF42 chip.
Schematics

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TWIN PEAK FILTER

The Twin Peak VCF is a LPF with two peaks. Variable separation and reversable sweep
of the peaks (for speech like sounds) is possible. It is also possible to invert one channel's
output for notch and HPF effects. The design is based on the Electro Harmonix Mini Synth filter.
Schematics

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FIXED FILTER BANK

A clone of the Moog 907 filter bank. Based on the Yusynth design, but simplified a bit.
Schematics

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PHASE SHIFTER

Voltage Controlled Phase Shifter with 4 or 6 stages and some adding/subtracting control.
It is made from a Roland Phase II.
Schematics

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COMB FILTER

The Voltage Controlled Comb Filter is made from a Korg Trident flanger, but it also
includes the choise of an Electric Mistress architecture. And then some adding/subtracting control.
Schematics

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WAVE MULTIPLIER

Wave Multiplier with voltage controlled drive and shape. First is a soft clipping VCA
and then a distortion stage based on the Korg PS-3100 waveform converter.
Schematics

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RING MODULATOR

A four quadrant multiplier, ICL8013, and a VC sine oscillator, XR2206.
Schematics

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FREQUENCY SHIFTER

This is a Doepfer A-126 VC Frequency Shifter and a Doepfer A-143-9 Quadrature VCLFO
that I have built on an MU panel. I have also included through-zero control of shift.
Schematics

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DUAL AMPLIFIER

Simply a CEM3330 dual VCA.
Schematics

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ANALOG DELAY

This is an Ibanez AD-80 with voltage control added.
Schematics

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SPRING REVERB

Voltage Controlled Spring Reverb. The PRE/POST switch determines if the VCA shall sit
before or after the reverb.
Schematics

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4 CHANNEL MIXER

A simple 4 channel mixer with inverted and non-inverted outputs.
(Yes, channel 4 has no attenuator)
Schematics

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ATTENUATOR/MIXER

Moog CP3A like half height attenuator and/or mixer.
Schematics

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PHASE LOCKED LOOP

A standard 4046 PLL plus a divider.
Schematics not finished yet, some issues to solve.

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DUAL MODULATION GENERATOR

Two MS-20 like MG:s with Audio/LF switch.
Schematics

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ENVELOPE GENERATOR

A CEM3310 Voltage Controlled Envelope Generator with additional features:
ATK OUT is a gate output, delayed as the attack time. Z. S. OUT is an envelope
that is level shifted so that sustain is always zero volt, like om MS-20, for e.g. pitch CV.
EXT switch is envelope time x 10, RPT is repeat.
Schematics

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SLOPE GENERATOR

The Slope Generator can act as an AD or AR envelope generator, LFO, slew limiter,
gate delay, gate duration and/or gate inverter. Think DUSG or Maths, but without voltage control.
Schematics

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EVENT GENERATOR

The Event Generator can be used as a complex envelope generator, an LFO or a simple sequencer.
Schematics

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SAMPLE & HOLD

Standard Sample/Hold with lag and clock sync.
Schematics

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DUAL QUANTIZER

The Doepfer A-156 Dual Quantizer placed on MU panel.
No schematics

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GATE SEQUENCER

A four channel, 8 step gate sequencer ih half height. Designed to work with the Q960.
Also includes a four bar counter and a gate multiplexer, following the bar counter or Q962.
Schematics

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ENVELOPE FOLLOWER

Envelope Follower. The usual stuff plus a mic preamp and an output after the rectifier.
Schematics

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DUAL ANALOG SWITCH

Two analog switches based on the DG-201.
Schematics

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DUAL VOLTAGE PROCESSOR

No rocket science, but often comes in handy.
Schematics

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DIVIDERS

Dividers for gates as well as audio.
Schematics

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LEVEL DECODER

The level decoder can be used as a waveform converter,
complex comparator or to extract gates out of LFO, envelope
or sequencer CV. There's also an analog sum output of all active gates.
Schematics

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CV/GATE BUSES

These half height modules are used to input gates and CV:s and then route
them to different modules by using the switches. The functions are defined by
internal routing.
No schematics

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JOYSTICK

The Joystick can be used both as a CV source and an attenuator, and has
two trigger buttons. Half height module.
Schematics

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POWER MODUEL

The Power Supply is a simple design with a toroid transformer, fullwave
rectifier and common 78/79 type linear regulators. The panel also supports
the connection of a CV/GATE keyboard. Half height module.
Schematics

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