design — construction — sound

Eurorack Module

X

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).

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

Soundfiles
2:05	Ringmodulation of Synthesizer and Rhythm machine X in: Korg MS-20 filtered VCO and noise with different filter settings;Y in: Rhythm machine
1:05	Ringmodulation of Rhythm machine and Trumpet X in: Rhythm machine; Y in: Preamplified trumpet; different X Offset settings
1:35	Ringmodulation of Rhythm machine and Cymbals X in: Rhythm machine; Y in: Preamplified cymbals; different X Offset settings
1:58	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
1:55	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.
2:47	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 https://soundcloud.com/cg-products/sets/x

Documentation

X documentation 1st page

X minijack panel drawing

Panel

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
+2
+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

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
+2,5	2
0	4
-4	7