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CV Cluster
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3D Model

The CV 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. These different voltages are the base voltage offset in a positive direction by the modulating voltage and the base voltage offset in a negative direction by the modulating voltage. A series of equal taps between these two points results in outputs that always maintain the base control voltage at its full amplitude, mixed with a differing amount of the modulating voltage. The center output has equal amounts of positive and negative modulation canceling each other out, and thus behaves as a straight-through connection for the base input.

Some ideas on how to use this module:
Feed a 1/V Octave input into the base input, and an envelope generator, LFO, sequencer etc. into the modulation input. Connect the outputs, starting with the center unmodulated output, and working both up and down, to a series of VCOs. While the modulation input remains at zero, all of the VCOs will track. As the modulation voltage increases, the VCOs connected to modulated outputs will shift in frequency away from the base, at an amount proportional to its position from the center output. For example, a small modulation voltage will de-tune the oscillators slightly, fattening the sound. A modulation CV of 5 volts will set each output 1 volt apart, setting the oscillators an octave apart. An envelope generator connected to the modulation input creates an interesting effect.

It can, of course, be used with audio frequency signals too, and may prove interesting when driving a cluster of wave multipliers or similar. Two audio signals fed to it could produce interesting stereo effects.

Note: The sum and differences produced by this module are voltage differences, NOT frequency differences. It is NOT a ring modulator.

PCB Dimensions: 1 " x 6" with 3.2mm fixing points 0.15" from the edges
Power Consumption: +12V @ -12V @
Build Guide

Original article, art & design copyright 2003 by Ken Stone

Email:  elby-designs@bigpond.com
© Copyright 2000. All rights reserved.     Revised: July 30, 2020