Serge synthesizer

From Wikipedia, the free encyclopedia
  (Redirected from Serge Modular)
Jump to: navigation, search
Serge Modular
Serge Modulars in the rack

The Serge synthesizer (aka Serge Modular or Serge Modular Music System) is an analogue modular synthesizer system originally developed by Serge Tcherepnin, Rich Gold and Randy Cohen at CalArts in late 1972. The first 20 Serge systems (then called "Tcherepnins") were built in 1973 in Tcherepnin's home.[1] Tcherepnin was a professor at CalArts at the time, and desired to create something like the exclusively expensive Buchla modular synthesizers "for the people that would be both inexpensive and powerful."[2] After building prototypes, Tcherepnin went on to develop kits for students to affordably build their own modular synthesizer. This led to Tcherepnin leaving CalArts in order to produce kits commercially, starting in 1974.[3] Commercial builds of Serge synthesizers are currently available from Sound Transform Systems (STS) in Hartland, Wisconsin, USA.

After leaving CalArts, Serge had a small factory on Western Avenue in Hollywood. He relocated to a three-story Victorian house on Haight Street in 1980. While the synthesizers were inexpensive compared to Moog, Buchla, and other manufacturers, Serge Tcherepnin's emphasis was always on providing musicians with quality equipment.

Serge synthesizers have been used by composers such as Michael Stearns and Kevin Braheny (who owned a 15-panel system dubbed The Mighty Serge). Serge synthesizers are known for their flexibility, audio quality and relative compactness. Other well-known musicians using Serge synthesizers include Malcom Cecil, whose studio was used in Stevie Wonder albums; Gary Chang, movie composer; Roger Powell, keyboard player for Todd Rundgren; and John Adams, composer.


Originally, the module configuration for Serge systems could be selected by the user. With module widths typically ranging from 1" to 3" (sometimes more in the case of sequencers), several modules could then be arranged on a 17-inch-wide panel (total of 16 inches of modules), resulting in a custom built panel. These were originally arranged by applying paper graphics to the metal panel, which later became metal self-applied graphics and finally graphics printed directly onto the metal panel.

In the early 1990s the business was transferred over to Rex Probe who renamed it Sound Transform Systems (STS). A number of changes were applied over the years including the end of systems being sold as kits and user selectable module arrangements. STS moved onto 17" pre-configured 'Shop' panels and then the half sized 'M-Class panel. These are smaller 8" panels, allowing a user more flexibility in module choice than the Shop Panels. These panels come with a center panel for power distribution that are 1" wide.

Early systems had custom graphics—or no graphics—depending upon the whims of the artist. Soon Serge adopted a series of geometric designs denoting signal types, input, outputs, and triggers. Later modules had more standard labelled graphics with blue, black, and red jacks for control voltages, audio signals, and triggers, respectively.

Serge modules did not distinguish between audio signal and control voltage jacks, all signals were patched from module to module via banana patch cords. Banana cables are of the most flexible in electronic patching and offer quick patching with a secure connection, most banana jacks can be stacked as well. The banana jacks are of the 4mm type and heavy insulated silicon cable is used. With a simple ground connection made between different units cross connection/modulation can be made between units.

One of the first Serge Modular synthesizer created became the machine used on the first Greenpeace anti-whaling expedition (1975) by William (Will) Jackson, to approximate whale sounds and broadcast them to whales in the open Pacific. (A photo of this can be found in the Vancouver Sun newspaper archives May 1975.)


The first generation of modules consisted of:

Dual voltage processor

Dual audio mixer

Peak and trough

Triple bidirectional router

Triple waveshaper

Gate (VCA)

Ring modulator

Envelope generator (wierd ASR)

Oscillator (VCO with waveshaper)

Dual negative slew

Dual positive slew

Triple comparator (plus Schmitt trigger)

Voltage controlled filter (2 pole state variable)

Send & Return (audio interface)

Programmer (4 stage controller, linkable for 8 / 12 stages))

Sequencer (10 step pulse only)


The Negative and Positive Slews, were able to function as envelope followers, low pass filters, modulating waveforms, subharmonic generators, and audio oscillators. The Programmer served as the performance interface, being a manually controlled sequencer. It could be patched to the (pulse) sequencer - some were hard-wired. These systems were essentially DIY.

Serge set up SMMS in 1974 and set about expanding and upgrading the range. This second generation of modules included:

Smooth and stepped function generator

Noise generator (later incl. S&H)

Phase shifter


Reverb (spring)

Analog shift register

Keyboard Envelope generator (VC ADSR)

He also upgraded the mixer, dual processor, Send & Return, Oscillator etc.

As well as working on the modular range Serge worked with others. He designed and built custom modules for Cecil and Margouleff's TONTO system (as used on several Stevie Wonder albums) and worked with Frank Eventoff on his Sonica and Rainmaker instruments.

Around 1976, Serge started to replace some of his old designs with a new generation of state-of-the-art designs, pioneered highly accurate 1V/Oct oscillators and high dynamic range VCAs (voltage controlled amplifiers) that enabled a new filter technology with low-noise and equal power multi-channel panning. A new panel graphics style was also introduced, replacing the geometric designs with a simpler layout.

In addition to fully featured standard synthesis modules such as voltage controlled oscillators, filters, and envelope generators, the Serge system includes esoteric audio signal processors such as a Wave Multiplier, a Frequency Shifter, an Analogue Delay as well as a very flexible touch-sensitive keyboard controller combined with a 16-stage analogue sequencer, known as the TKB. The new modules included:

Quad VCA

Universal Equal Power Audio Panner

PCO (high quality VCO)

NTO (PCO plus waveshaping, FM etc)

Variable bandwidth vcf

Variable slope vcf

Variable Q VCF (also extended range VCF)

Wave multipliers

Dual universal slope generator / Dual transient generator

Touch activated keyboard sequencer TKB

Extended ADSR

Pitch and envelope follower (a Gentle Electric design)

He also extended the range of mixers and CV processors. Many of the circuit boards could by used in a variety of ways, and an exhaustive list of modules would be difficult to compile. Filter banks were made in small numbers, but it is uncertain if any hex panners were ever built.

While these new modules replaced many of the older modules, other earlier modules remained in production.

Around 1979, a fourth generation of modules started to appear, complimenting the 1976 modules and replacing some earlier modules. The current Serge panel graphics style also appeared around this time. The new modules included:

Active processor

Resonant equalizer

4//6/7/8 step sequencer

Divide/n comparator, dual comparator, Schmitt trigger

Wilson Analog Delay

Balanced modulator


Frequency shifter

Quadrature oscillator

Dual VCA

Envelope follower / preamp

N voice controller

Also, new electronics were designed for the audio mixer/processor/scaling/buffering modules and the VCA/panners, and the "paper face" panel graphics were replaced with metallized plastic film. Throughout this period, systems were available built or as kits - boards supplied pre-built and tested but you wire the panels up yourself.

The N voice controller was a polyphonic interface which worked with a modified Casio keyboard. Sadly it appeared around 1982, just a year before MIDI.

The 1980s were not good times for modular synthesizer manufacturers. I am not aware of any more modules being designed by Serge. In the early 1990s, Sound Transform Systems took over the range and added a few of their own. These included:

Pulse Divider

Boolean Logic

Audio Mixer w/ Phase Switch

Midi CV (short lived)

They also introduced new variations on existing modules and were able to use better quality parts and quality control (component quality improved massively through the 1980s accompanied by a drop in prices).

Originally Serge panels had all possible holes punched, and the panel labels covered over unused holes. While this was very versatile and allowed for upgrading or changing panels, it could look a bit scruffy. STS introduced graphics directly onto their panels, sacrificing some versatility for a more solid, professional look. They also introduced a range of standard "shop panel" configurations. More recently, STS changed to smaller M modules, where two narrower preconfigured panels fit each side of a centre power modules.

The 21st century has seen the rise of independent builders making printed circuit boards, kits, and finished panels available to the musician at prices that reflect the original spirit that Serge Tcherepnin brought to the field back in the 1970s. These builders are sending royalties back to Tcherepnin for each module or panel sold. Ken Stone was the first to open these floodgates and makes many of the PC boards available for purchase. Sometimes the circuitry has been redesigned to reflect available parts as well as optimizing circuit flow. He also makes his own compatible designs available as well as the designs of others.


  1. ^ Vail 2000, p. 150
  2. ^ Vail 2000, p. 149
  3. ^ Vail 2000, p. 151

External links[edit]