The "Cat Girl Synth" is a 4U Modular Synthesizer
designed by Ken Stone.
The synthesizer is mostly analog,
and is based on the 1V/Octave standards set by Robert Moog.
Use this twin sub-oscillator with one or two VCOs for fat sounding lead or harmonies, or with a VCO and an LFO for harmonic sequences, or as a pattern based sequencer
A rhythm and timing accessory that generates a burst of gate or trigger pulses at various speeds. Used for washboard, maracas or similar rapid-burst percussive effects when connected to the appropriate sound generating device
Use this as a timing accessory for sequencers, or with a VCO for frequency trills like those of the old 8-bit computer games. Unilke other voltage controlled dividers, this one preserves the pulse width of the incoming signal.
This module can be used as a simple gate delay, a semi-random melody generator, a comparator, and a gate/clock controlled comparator. All in all, a very versatile module.
This module is the embodiment of the classic twin-T circuit in a form that is suitable for connection to modular synthesizers. It contains two separate drum sounds, each individually triggered, as well as something unique - adjustable harmonic content
This module contains a pair of two or three tone chimes that are suitable for connection to modular synthesizers. Each chime sound is created by modulating two or three square wave oscillators together, and applying an envelope to the result. Each chime is individually triggered.
This module is a much expanded version of the Psycho LFO, featuring six free-running oscillators, each variable between LFO and audio ranges, two of which can be switched to have triangular wave outputs. Each oscillator can be switched between low and high ranges, as well as off, and also has a rate LED, to allow visual determination of the frequency at which it is running. As per the original, there are also level and glide controls
The purpose of this module is to divide down a system master clock (e.g. a VCLFO) to drive an array of sequencers or other timed events. The different phase outputs are to allow for modules that may trigger from the falling edge of a wave, or to allow for deliberate lagging of an event. It would for example be possible to have two sequencers running from this unit, one at 1/8 of the frequency of the other, their outputs being mixed to give a sequence that changes fundamental pitch each eight notes.
This module contains a pair of two gate to trigger converters, allowing key-down gate signals, or those from gate sequencers etc. to be converted into a much narrower trigger signal as required by some percussive effects. These may come in handy when adapting various drum sound generators to synthesizer use
This module is the analog implementation of some basic logic elements. Instead of dealing with binary inputs, the "logic" is applied to whatever voltages are present on the inputs. When the AND element is fed several voltages, the output will equal the the lowest input voltage. The NAND output will be the inversion around 0 volts of the AND output. When the OR element is fed several voltages, the output will equal the the highest input voltage. The NOR output will be the inversion around 0 volts of the OR output. Apparently the AND and OR functions are the same thing as "peak" and "trough" on old Serge synthesizers, though they are implemented somewhat differently.
The idea for this project came from the fabled middle section of the Serge wave multipliers. It could equally be described as a wave folder or a timbre modulator.
This module is a very standard pseudo-random digital noise source with a few enhancements. Instead of running a fixed high frequency clock, a VCO is used instead, allowing for unusual sweeps, and for reducing the speed right down to a series of random pulses. The internal linear VCO can also be bypassed so an external source such as a 1V/oct VCO or LFO can be substituted. It has pink and white noise outputs, and two separate (unique) digital outputs for use in triggering other circuits.
The name of this module is a play on its function. Put simply, it generates a series of semi-random or themed stepped control voltages, or if you prefer, white and pink control voltages. The pink function is probably better known as 1/f.
The CGS34 ASR is a sequential sample and hold module for producing arabesque-like forms in musical space. Whenever pulsed, the previously held voltage is sent down the line to three consecutive outputs to produce the electrical equivalent of a canonic musical structure.
This module is a "tribute" module, based on the awesome Steiner-Parker Synthacon VCF. Its sound is quite unlike the Moog ladder, and has a lot of character.
This module consists of several parts, a pulse divider with integer divisions between 2 and 8, and several logic elements. The divider is used to generate interrelated pulses for use in creating poly-rhythms, and unusual sequences or as a sub-oscillator/sub harmonic generator.
As well as the pulse divider, there are also four boolean logic elements, two inverters an OR gate and an AND gate for the processing of gate and trigger signals
The C.V. cluster is an unusual kind of mixer. It takes two input voltages - a base control voltage, and a modulating control voltage, and creates the sum and differences of them, as well as a range of voltage in between.
The Saw Pitch Shifter is an experimental combination of op-amp summers and comparators with surprising results, ranging from complex wave shaping to pitch shifting of saw tooth waves.
The Quad Logic Gate is a very simple module that can be built in one of five flavors : XOR, OR, AND, NOR and NAND. It is a simple way to gain additional control of gate and trigger pulses within a system. It can also be used for some simple signal multiplying. The XOR is well known as a square wave "ring modulator", though interesing effects can also be generated using the other configurations. Each gate has an inbuilt LED to indicate the status of the outputof that gate.
The Diatonic Converter is an adapter for projects such as the Infinite Melody and Gated Comparator, constricting their outputs to the notes of a major or minor diatonic scale instead of the chromatic scale. A single control line selects between major and minor. It can also be used as a stand-alone module when driven from other systhesizer gate events.
The Cascade Mixer is an experimental mixer that can be built in one of several ways - a unity gain cascaded mixer, a binary weighted (or scaled) mixer, or as a staircase generator when coupled with a binary counter.
The Cynare drum simulator is the third in the series of CGS drum simulators. It generates a single drum sound that can be adjusted to sound like a cymbal, hi-hat, snare drum, electronic drum, or numerous other percussive sounds. It is a complete dedicated synthesizer in its own right, including six oscillators, a noise source, a mixer, an envelope generator, a VCF and a VCA.
This VCO started out life as a replacement for the original VCOs in Kens' '73 Serge, so it replicates a lot of the functionality of that module. Of course there have been numerous enhancements to the design as well, making it right at home in a 1 volt per octave synthesizer.
The weighted random switch is another module for introducing unpredictability into synthesizers. The original requirement was for a circuit that would, upon receiving a clock signal, randomly direct a single input to one of four outputs, but with a twist. Four knobs or control voltages could be used to sway the likelihood of one or more outputs being selected over the others.
The Simple Wave Folder is an ideal project for beginners. The effect produced is not unlike that of the middle section of the Serge Wave Multipler (CGS513 - VCM2 Sweeper).
This board is an add-on for the Pulse Divider and Boolean Logic module, adding XOR and XNOR fucntionality. It can also be used to compare two analog signals, either positive or negative in value.
The Analog Switch Matrix is a complex router, allowing one input to be switched between four outputs, or vice versa, or even to route one signal through one of four external effects (e.g. wave multipliers, filters etc.). It can also be used as four independent analog switches.
The purpose of the Gate Converter is to turn standard positive gate signals into negative to postitive going gate signal. This is particularly handy when interfacing to other manufacturer's modules that require a zero crossing singal to operate. It can also be used to convert assorted LFO or VCO signals to square or rectangular waves, to extract some form of gate signal from an envelope and so on.
This is a strange mixture of a VCO and a switched capacitor filter based on the filter presented by Jan Hall in Electronotes. If you are after something different, this fits the bill. After all, how many filters have a sync input?
The Utility LFO is a dual manually controlled LFO offering a number of standard and combined outputs for general low frequency work, such as filter and phaser sweeps, clocking sequencers and so on.
Serge style programmer/sequencer.
The Programmer/Sequencer is a Serge inpired multi-stage sequencer. Unlike most sequencers, this one makes no use of binary counters. Rather, it uses a set of individual stages, each one directly accessible.
This is an external input amplifier with extra provisions so that it can also be used as an effects pedal interface. There are three identical amplifiers on the board.
The slope detector is an event-driven gate/trigger generating device. It monitors a control voltage, and triggers one of three "gate" output dependent on what the control voltage is doing.
Tube based Voltage Controlled Amplifier / timbral gate. While this module basically operates as a VCA, it does add a degree of distortion to the signal. How much distortion depends on how hard it is driven. Add feedback and it begins to oscillate, syncing to the incoming signal to some extent. All this while running on a standard synthesizer power supply, with no extra heater supply required.
The CGS81 is a circuit for adding and inverting control voltages. Full processing control of 4 input voltages is provided. A manual offset voltage can be set using [OFFSET] to be added to the other four inputs
This is a redesigned circuit board for the CGS359 Programmer/Sequencer. Unlike that version, this one has no panel-format specific PCBs. The column boards have been replaced with boards that contain 8 stages. These can be used to drive pots or switches in any panel configuration you wish.
This PCB is designed to help mounting and wiring pots or LEDs to panels. It uses the 1 inch horizontal spacing standard of Serge panels, and provides mounting for 16 pots or LEDs.
This is a basic reverb module constructed around the Belton BTDR-2H Reverb Module. From a single input, two channels of raw reverb are generated. Mix outputs are also provided, allowing the input/reverb mix to be controlled via a panel pot. An additional feedback function is provided for emphasizing the effect, or even for generating screaming feedback
This module is the combination of a quad comparator "voting system" and memory cell (flip-flop). It can be built in many ways to suit the builder's needs. For example, if the memory cell functions are not required, they can be omitted. Alternatively, the panel presence of the comparators can be greatly reduced if the memory cell is the primary interest.
The matrix mixer is a multiple input, four output bipolar or unipolar DC coupled mixer, for mixing control voltages or audio signals. In cases where you require several different mixes from a common set of signals, this module is ideal.
This module is a variation on the Classic Buchla Low Pass Gate module
developed by Peter Grenader and released here as his gift to the Serge DIY
community.
A rhythm and timing accessory that generates a burst of gate or trigger pulses at various speeds. Used for washboard, maracas or similar rapid-burst percussive effects when connected to the appropriate sound generating device
Use this as a timing accessory for sequencers, or with a VCO for frequency trills like those of the old 8-bit computer games. Unilke other voltage controlled dividers, this one preserves the pulse width of the incoming signal.
This module can be used as a simple gate delay, a semi-random melody generator, a comparator, and a gate/clock controlled comparator. All in all, a very versatile module.
This module is a much expanded version of the Psycho LFO, featuring six free-running oscillators, each variable between LFO and audio ranges, two of which can be switched to have triangular wave outputs. Each oscillator can be switched between low and high ranges, as well as off, and also has a rate LED, to allow visual determination of the frequency at which it is running. As per the original, there are also level and glide controls
This module is the embodiment of the classic twin-T circuit in a form that is suitable for connection to modular synthesizers. It contains two separate drum sounds, each individually triggered, as well as something unique - adjustable harmonic content
This module allows for realistic simulation of natural musical instruments by providing fixed bandpass resonances which are an important determining factor in the timbre of mechanical tone generators.
The CGS334 ASR is a sequential sample and hold module for producing arabesque-like forms in musical space. Whenever pulsed, the previously held voltage is sent down the line to three consecutive outputs to produce the electrical equivalent of a canonic musical structure.
This module is a "tribute" module, based on the awesome Steiner-Parker Synthacon VCF. Its sound is quite unlike the Moog ladder, and has a lot of character.
The CGS336 is a pulse divider with integer divisions between 2 and 8, and several logic elements and is the main section from the CGS36. The divider is used to generate interrelated pulses for use in creating poly-rhythms, and unusual sequences or as a sub-oscillator/sub harmonic generator.
The C.V. cluster is an unusual kind of mixer. It takes two input voltages - a base control voltage, and a modulating control voltage, and creates the sum and differences of them, as well as a range of voltage in between.
This VCO started out life as a replacement for the original VCOs in Kens' '73 Serge, so it replicates a lot of the functionality of that module. Of course there have been numerous enhancements to the design as well, making it right at home in a 1 volt per octave synthesizer.
The Analog Switch Matrix is a complex router, allowing one input to be switched between four outputs, or vice versa, or even to route one signal through one of four external effects (e.g. wave multipliers, filters etc.). It can also be used as four independent analog switches.
The Programmer/Sequencer is a Serge inpired multi-stage sequencer. Unlike most sequencers, this one makes no use of binary counters. Rather, it uses a set of individual stages, each one directly accessible.
This is an external input amplifier with extra provisions so that it can also be used as an effects pedal interface. There are three identical amplifiers on the board.
The CGS381 is a circuit for adding and inverting control voltages. Full processing control of 4 input voltages is provided. A manual offset voltage can be set using [OFFSET] to be added to the other four inputs
This is a redesigned circuit board for the CGS359 Programmer/Sequencer. Unlike that version, this one has no panel-format specific PCBs. The column boards have been replaced with boards that contain 8 stages. These can be used to drive pots or switches in any panel configuration you wish.
This is a basic reverb module constructed around the Belton BTDR-2H Reverb Module. From a single input, two channels of raw reverb are generated. Mix outputs are also provided, allowing the input/reverb mix to be controlled via a panel pot. An additional feedback function is provided for emphasizing the effect, or even for generating screaming feedback
The CGS405 is the the Boolean Logic section from the CGS36. There are four boolean logic elements, an inverter (NOT gate) an OR gate an AND gate and an XOR gate for the processing of gate and trigger signals
This Joystick Controller uses two DC mixers, one per axis, each mixing a front panel controlled D.C.
offset and the voltage out of the joystick-in/1-out
A re-design of the CGS19 providing 2 independent chime outputs
CGS SERGE Modules
Adaptations of several classic Serge modules.
These designs have been done with the permission and collaboration of Serge Tcherepnin himself.
All designs are produced under license from Serge.
This is an adaptation of the original Serge Envelope Generator from the early "R" series PCBs.
This is NOT an ADSR style generator, and can be used as an LFO.
This is the Serge Negative Slew which was part of the original line of modules. Ultimately this would go on to be replaced by the Dual Universal Slope Generator. It can be used as a falling sawtooth LFO, VCO, or as the name suggests, a lag/slew for falling voltages. Rising voltages are passed unhindered.
This is the Serge Positive Slew which was part of the original line of modules. Ultimately this would go on to be replaced by the Dual Universal Slope Generator. It can be used as a rising sawtooth LFO, VCO, a simple envelope generator or as the name suggests, a lag/slew for rising voltages. Falling voltages are passed unhindered.
This module is a variation on the 1973 Classic Serge Peak and Trough module. It is much like the Analog Logic Voltage processor, though a little less precise. It is presented here for those who want to build themselves a classic Serge.
This module is a variation on the 1973 Classic Serge Triple Wave Shaper. This design started off as a wave shaper for the original Serge VCO, and has persisted as an available module since that time.
The Triple Bi-Directional Router is a group of three switches each of which can route one input to either of two outputs, or either of two inputs to one output according to a pulse or control voltage level. It can also be assembled to sequentially route one input to one of four outputs, or one of four inputs to one output.
The TRIPLE COMPARATOR consists of three independent functions which are useful in the production of square waves and variable pulse waves. The Comparator reference level can be a time-varying control voltage, a complex audio signal, or a fixed preset voltage. Additionally, the comparators are useful for level detection and for logic decisions based on amplitude. The module also contains a single, non-adjustable, Schmitt trigger
The Serge noise module can be built in several ways. In it's simplest form, it contains three basic outputs, White noise, Pink noise, and a random voltage suitable for use with Sample and Hold modules. An optional Sample and Hold circuit is included on the PCB. Alternatively, the basic version may be coupled with the CGS92 Serge Smooth and Stepped Generator to make the Random Voltage Generator module.
The Dual Channel Stereo Mixer (DCSM) Is An Alternative Output VCA/Mixer/Panner For Two And Three-Panel Systems. The Dual
Channel Stereo Mixer is used for the standard output level control (or enveloping) and for voltage controlled panning.
The VARIABLE Q VCF (VCFQ) is an excellent general-purpose VCF offering simultaneous low-pass, high-pass, band-pass and notch (band-reject) outputs. The resonance (Q) of this filter is dynamically variable by manual or voltage control.
Used CGS108
The Universal Slope Generator (USG) is the ultimate patch-programmable control voltage generator in the 4U Serge system. At least two are recommended for almost every 4U Serge system, and in most cases, a number of these are desirable. People familiar with the previous series of "slewing" modules know about the importance of this kind of function in a large patchable synthesizer system.
The RESONANT EQUALIZER (EQ) is a unique ten-band filter designed specifically for electronic sound synthesis and processing. Except for the top and bottom frequency bands, all other bands are spaced at an interval of a major seventh. This non-standard spacing avoids the very common effect of an accentuated resonance in one key, as will be the effect from graphic equalizers with octave or third-octave spacing between bands. Spacing by octaves will reinforce a regular overtone structure for one musical key, thereby producing regularly spaced formants accenting a particular tonality. The Resonant Equalizer's band spacing are much more interesting, producing formant peaks and valleys that are similar to those in acoustic instument sounds.
The Divide-N Comparator consists of two section: a comparator and a voltage-controlled pulse divider. The divider section outputs a pulse once every 'N' comparator pulses, where 'N' is a number from 1 to 31 settable with a control voltage at the dividers [VC] input (or manually via the [1-31] knob). Additionally, the divider outputs a staircase wave with 'N' steps. This will produce whole-tone steps when plugged in to the 1V/Octave input of a VCO.
The CGS502 provides a simple means to turn any control voltage in to voltage steps corresponding to well tuned (equal-tempered) tones of musical scale. It is scaled to 1V/Octave so a 0V to +5V envelope at one of the inputs produces a staircase of voltages corresponding to a chromatic scale.
The Serge
Preamp and (new) Envelope Detector provide an exceptionally
responsive link between external audio signals and the CGS-Serge
synthesizer modules. The key to this responsivity comes from
the fact that the detector was designed to respond to the POWER
rather than to the AMPLITUDE of a sound.
The Serge
Preamp and (new) Envelope Detector provide an exceptionally
responsive link between external audio signals and the CGS-Serge
synthesizer modules. The key to this responsivity comes from
the fact that the detector was designed to respond to the POWER
rather than to the AMPLITUDE of a sound.
The Transient Generator is a useful, space-effective unit to be used for many of the same functions as the Universal Slope Generator. Common uses of the Transient Generator are for simple "AR"'-type envelope generation, as a dual voltage-controlled low frequency oscillator, or as a voltage-controlled clock (especially suitable for clocking the Touch Keyboard Sequencer or any of the Sequencer Programmers) . These functions can be patched with the Universal Slope Generator, but since many of the features are left unused in these patches, the Transient Generator provides the same function while using less front Panel space"
The VARIABLE Q VCF (VCFQ) is an excellent general-purpose VCF offering simultaneous low-pass, high-pass, band-pass and notch (band-reject) outputs. The resonance (Q) of this filter is dynamically variable by manual or voltage control.
Uses CGS508
This is an adaptation of the original Serge VCM containing three distinct sections for the addition of harmonics to a signal.
Please note: this PCB is a 3" wide PCB as opposed to the 2" width of the CGS113
The Universal Slope Generator (USG) is the ultimate patch-programmable control voltage generator in the 4U Serge system. At least two are recommended for almost every 4U Serge system, and in most cases, a number of these are desirable. People familiar with the previous series of "slewing" modules know about the importance of this kind of function in a large patchable synthesizer system.
The RESONANT EQUALIZER is a unique ten-band filter designed specifically for electronic sound synthesis and processing. Except for the top and bottom frequency bands, all other bands are spaced at an interval of a major seventh. This non-standard spacing avoids the very common effect of an accentuated resonance in one key, as will be the effect from graphic equalizers with octave or third-octave spacing between bands. Spacing by octaves will reinforce a regular overtone structure for one musical key, thereby producing regularly spaced formants accenting a particular tonality. The Resonant Equalizer's band spacing are much more interesting, producing formant peaks and valleys that are similar to those in acoustic instument sounds.
This is an adaptation of the original Serge Envelope Generator from the early "R" series PCBs.
This is NOT an ADSR style generator, and can be used as an LFO.
The CGS579 provides a means to smoothly voltage control the index of modulation, from 0% modulation of the signal by the carrier, through to 50% modulation (otherwise known as amplitude modulation) and 100% ring modulation with excellent carrier rejection.
This is the Serge Negative Slew which was part of the original line of modules. Ultimately this would go on to be replaced by the Dual Universal Slope Generator. It can be used as a falling sawtooth LFO, VCO, or as the name suggests, a lag/slew for falling voltages. Rising voltages are passed unhindered.
This module is a variation on the 1973 Classic Serge Triple Wave Shaper. This design started off as a wave shaper for the original Serge VCO, and has persisted as a dedicated module since that time.
The TRIPLE COMPARATOR consists of three independent functions which are useful in the production of square waves and variable pulse waves. The Comparator reference level can be a time-varying control voltage, a complex audio signal, or a fixed preset voltage. Additionally, the comparators are useful for level detection and for logic decisions based on amplitude. The module also contains a single, non-adjustable, Schmitt trigger
The Serge Noise module can be built in several ways. In it's simplest form, it contains three basic outputs, White noise, Pink noise, and a random voltage suitable for use with Sample and Hold modules. An optional Sample and Hold circuit is included on the PCB. Alternatively, the basic version may be coupled with the CGS92 Serge Smooth and Stepped Generator to make the Random Voltage Generator module.
ALL PCB's are latest revision - PCB images where used are for guidance only and may not reflect the current revision
(**) PCBs for these items are no longer available. Component/Hardware Kits are still available on request (CGSxxx) These PCBs have been superceeded by the design in the link (NB: it has been decided that all updated designs will use
an extended module code number to identify that it is a newer design eg CGS77 will become CGS577.
Unfortunately this decision was made after some updated
PCBs had been released and so they may
still have the older number for example, the CGS334 is still marked as the CGS34
Serge designs will be CGS5xx while CGS designs will be CGS3xx)
Consistency Across the CGS Platform
Currently, some CGS designs are designed for a +/-15V supply while others are designed for a +/-12V supply (although they can all be swapped as described in the documentation). Moving forward all designs will be updated for a standard +/-12V supply to achieve uniformity of the design and documentation in line with our Best of CGS products (BoCGS). This move will be reflected in our Component Kits which will contain, where applicable, components selected for +/-12V power. It will, however, take some time to get schematics and PCB overlays updated so users are advised to check the supporting documentation and BOMs prior to starting any build. What is the impact?.
Please also note that our Hardware Kits are being optimised to provide the panel components required to use the associated PCB as it appears in our BoCGS/Voltron range of panels. For example, the CGS348 is presented as a 'Compact Oscillator' in the BoCGS BOG and consequently does not use all of the input/output/features that the design offers. As we slowly update the PCB designs and our catalogue we will include example front panel layouts that show what the Hardware Kit covers. If you require to generate a fuller build then please feel free to email us with your requirements and we can provide a quote for the additional parts.
Legal PCBs
It has been bought to our attention that there are some sources selling unauthorised copies of the CGS and CGS-SERGE PCBs.We strongly recommend purchasing PCBs either direct from ELBY Designs or via the approved supplier network which currently comprises Modular Addict and SynthCube
We will only provide techncial support to builders who have purchased from an official source (proof of purchase will be required
