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. It also includes an
8-input DC mixer.
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 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 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 CGS322 is a series of dividers and
"phase shifters" for converting a single clock pulse
train into an array of frequencies. The incoming
clock signal is divided into successive clock
signals, each half the frequency (twice the period)
of the previous. Three other outputs, each
successively shifted by 90°; are also provided.
While the first stage has outputs for 90° and 270°,
the usability of these outputs is dependent entirely
on the waveshape of the clock signal, with square
being optimal.
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 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. d.
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
