Eurorack Module


4-Quadrant Multiplier

Universal usable modulator module. The two input voltages X in and Y in are multiplied with each other. The results are ring/amplitude modulated sounds or control voltages. In addition, one input (X) is equipped with a switchable exponential converter for VCA-like applications and more. 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 is 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.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 is 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 banana version

X minijack version

  • 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

Doku X miniature

X Panel Drawing

X minijack sideview right

Side view right
X minijack sideview left

Side view left
X banana sideview right

banana version side view

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