CG Products
design — construction — sound

Eurorack Module


4-Quadrant Multiplier

Modulator module for universal use. The two input voltages X in and Y in are multiplying each other. The results are ring/amplitude modulated sounds or control voltages. One input (X) is equipped with a switchable exponential converter for VCA-like applications etc.. The X input also has a manual level control to amplify or attenuate the input signal, an inversion switch and an adjustable offset voltage, which will be added to the X input. By using these two control knobs, one has a ‚dry/wet‘ style control over the Y input and the modulated signal. In addition, there is a little red LED indicating when this input gets overdriven (from Rev.4). The output (W out) is internally attenuated to ensure that the product voltage of X×Y is almost in the range between the ±12V voltage supply. 4-quadrant means: In comparison to a VCA (2-quadrant operation), a multiplier is working both with positive and negative control voltages, causing a ± polarity inversion of the modulated signal (= 4-quadrant operation).
X frontal view minijack version
Front view
  • Working both with audio and CV signals
  • Ring / amplitude modulation
  • Voltage controlled amplification
  • Exponential conversion
  • Wave shaping
  • Dynamic expansion
  • One input with adjustable level and offset
  • Easy to use
  • Optional with banana or 3,5mm minijack
  • Width: 6 HP
  • Dimensions: 128,5 mm x 30,2 mm
  • Depth: 35mm
  • Supply voltage: ±12V
  • Current consumption: ≈25mA



Ringmodulation of Synthesizer and Rhythm machine X in: Korg MS-20 filtered VCO and noise with different filter settings;Y in: Rhythm machine


Ringmodulation of Rhythm machine and Trumpet X in: Rhythm machine; Y in: Preamplified trumpet; different X Offset settings


Ringmodulation of Rhythm machine and Cymbals X in: Rhythm machine; Y in: Preamplified cymbals; different X Offset settings


Stereo panorama control with 2 X modules X in 1: triangle/squarewave, X in 2: triangle/squarewave inverted; Y in 1+2: Rhythm machine / VCO


Envelope shaping with 2 X modules X in1+X in2: trianglewave; Y in 1: VCO; Y in 2: Noise In exponential mode, depending on X Offset and X Level settings, different modulation waveforms can be achieved.


Noise modulation with 2 X modules and Delay1022 Xin1+Xin2 (exponential mode): pink noise, Yin1: white noise; W out1: Delay In Y in2: +10V DC voltage W out2: Delay time CV input Multiplier 1 (modulating white noise) is followed by the delay (delay time modulated by multiplier 2)

Or listen on


PDF Download

X documentation 1st page
X minijack panel drawing
X minijack side view right
Side view right
X minijack side view left
Side view left
X banana version front view
Banana version

Block Diagram

X svg Block Diagram

Examples (linear mode)

Linear mode: switch ‚lin/exp.‘ in upper position
X in or Y in = 0 ⇨ W out = 0 X in polarity ≠ Y in polarity ⇨ W out = negative
X in 0 ± + +
Y in ± 0 + +
W out 0 0 + +
X Offset X in Y in W out
0 X in Sinewave Y in triangle wave W out Offset: 0
+2 X in Sinewave Y in triangle wave W out Offset: +2
+4 X in Sinewave Y in triangle wave W out Offset: +4

Examples (exponential mode)

X Level: ≈3 (≙ X in amplification ≈ 1); exponential mode: switch ‚lin/exp.‘ in lower position
X Offset X in Y in W out
+3,5 X in trianglewave Y in exponential mode W out expnential mode
Due to the rectifying characteristic of the exponential mode, with different settings of the X input level and X offset several modulation shapes can be achieved for Y in (Y in: +10V DC voltage)
X Offset X in Level X in (ca. 8V pp) W out
+3,5 1 X in trianglewave W out Offset: +3,5
+2,5 2 X in trianglewave W out Offset: +2,5
0 4 X in trianglewave W out Offset: 0
-4 7 X in trianglewave W out Offset: -4