background image

The Corgasmatron is a two independent multi mode filters and a cross fader mounted behind a 
16HP Eurorack panel. The Corgasmatron's sound can range from ultra clean and precise, to 
extremely ballsy and dirty.The resonance is incredibly musical and interesting and is prime for 
all sorts of experimenting and sound design. The normalling, routing and cv options have been 
carefully selected to allow for a lot of control over the modules functionality and capabilities.

The original circuit was designed by analog guru david g. dixon after carefully studying and 
analyzing the classic korg ms-20 filter. His work resulted in a completely original circuit based 
around ssm2164 vca chips. This design is capable of almost identical results but is far more 
versatile. This is not a clone, it is an entirely new and modern circuit with many enhancements.

Corgasmatron Manual v1.0

Page 1 of 10

Key features: 

• 16HP and shallow (two pcbs in parallel so it is 

skiff friendly) 

• two independent filters, each with LP, HP and 

Notch modes. 

• Unique resonant (Q) drive control 
• A Switch links the two filters allowing both 

parallel and serial routing via normals to input B 
(which can be broken by inserting a cable at 
input B). 

• Oscillates very easily and can be used as a 

dual sine VCO. Using the resonance controls 
this Sine shape can be colored. 

• 1V/Oct inputs for each filter
• Built in full featured cross fader allows voltage 

controlled xfading between the two filters. The 
Xfade has a switch to select either unipolar 
(e.g. envelopes) or bipolar (e.g. lfo) control of 
the xfade position. There is also a switch to 
select direction. With nothing plugged into the 
Xfade jack the xfade knob controls the fade 
position. When an external CV is patched in the 
same knob acts as an attenuator for the control 
signal. 

• Jumpers on the back to select "modern" or 

"vintage" resonant modes (two different 
feedback paths for the resonance that use 
different diodes) 

• Expansion jacks for adding additional filter 

inputs and VC control of resonance

Summary of Contents for Corgasmatron

Page 1: ...es 16HP and shallow two pcbs in parallel so it is skiff friendly two independent filters each with LP HP and Notch modes Unique resonant Q drive control A Switch links the two filters allowing both parallel and serial routing via normals to input B which can be broken by inserting a cable at input B Oscillates very easily and can be used as a dual sine VCO Using the resonance controls this Sine sh...

Page 2: ...nce This control is also used to alter the timbre of the resonant sound if the filter is self oscillating 5 FM1 Unipolar attenuator for FM1 input 6 IN A Input attenuator controls the level into the filter For classic tone keep this below 12 oʼclock Higher gain will suppress the resonance of the filter and change its tone The combination of IN A level Q and Q Drive knobs can alter the tone of the f...

Page 3: ...er A Patch a audio signal here to be filtered The knob IN A attenuates this signal The input signal level alters the tone of the filter circuit and the resonance behavior For classic filter tone set the IN A knob to 11 oʼclock when using standard level modular VCOs 1V Oct A CV input for filter frequency calibrated for 1V oct standard By patching the 1V Oct output of your keyboard or MIDI to CV con...

Page 4: ...1 Khz set routing configuration to parallel and monitor out the MIX out Turn the Xfade front panel knob fully CW so as to only pass filter B Now adjust the trimmer slowly until the filter A is no longer heard This is calibrated at the factory 2 jumper Q behavior selection filter B This jumper selects different diodes for the Q circuit 1 2 is Modern mode 2 3 is Vintage mode ...

Page 5: ... VCA inserted between the pins labeled Q will enable VC control over Q 5 1V oct Adjustment of filter A and B Although these are calibrated at the factory vibrations during shipping variance between power supply voltages and component tolerances changing over time can cause the filter to move out of tune Use this trimmers to calibrate the 1V oct response of the filter if you need to See page 6 for ...

Page 6: ...requency meter into Out A or use headphones speakers to listen to the output if tuning by ear 4 Make note of your base frequency and then using your CV source increase it by one octave If the new octave is sharp relative to the base note then adjust the trim pot to make the note sharper note this may be counterintuitive If the new octave is flat relative to the base note then adjust the trim pot t...

Page 7: ...Corgasmatron block diagram Corgasmatron Manual v1 0 Page 7 of 10 ...

Page 8: ...A Audio output comes from MIX Patch according to the chart above to create the classic VCO VCF VCA voice Tips Patching a CV controller such as a joystick into FM2 A and setting both FM2 knobs to the same setting will enable you to control both filter cutoffs simultaneously Use FM1 inputs for both filters for different modulation such as velocity to VCF B Use the Q on VCF A to give a bass boost Adj...

Page 9: ...Specifications Width 16 HP Depth 35mm Current Draw 12v 70ma 12v 67ma Expected input 5v peak to peak OTA component Cool Audio SSM2164 Credits Original Corgasmatron design David Dixon Eurorack conversion PCB design and realization Danjel van Tjin Manual written by Haven Siguenza Danjel van Tjin David Dixon Copyright 2011 Intellijel Designs Inc Corgasmatron Manual v1 0 Page 9 of 10 ...

Page 10: ...Made in Canada Corgasmatron Manual v1 0 Page 10 of 10 ...

Reviews: