Mutated: Veils

Mutated: Veils - This DIY Veils PCB is four VCAs with an adjustable response curve. Veils’ outputs are daisy-chained, allowing adjacent groups of 2, 3, or all 4 channels, to be mixed together.

This is a PCB set in the Eurorack format.

Availability: In stock





Veils provides four VCAs with an adjustable response curve. Veils’ outputs are daisy-chained, allowing adjacent groups of 2, 3, or all 4 channels, to be mixed together.


A. Gain CV amount. Amount of gain (amplitude) modulation from the CV input (4), or direct gain control when no cable is patched in the CV input. When this knob is turned fully clockwise, a CV of +5V yields a gain of 1 (0dB), and a CV above +5V might cause distortion. Veils does not provide any offset control - a module like Shades or Blinds can be used to pre-process the gain CV to offset it.

B. Response curve. Continuously variable between exponential and linear. Because the exponential function grows rapidly, very high gains (above 10) can be achieved with an exponential response curve. Beware of clipping!

1. DC-coupled signal input. Accepts audio or CV signals.

2. Signal output. When no patch cable is plugged into an output, the signal from this channel is routed to the next channel. For example, when no patch cable is patched into output 1, output 2 will contain the sum of channel 2 and channel 1. If nothing is patched into outputs 1, 2 and 3, output 4 will contain the sum of all four channels.

3. Indicator LED. Brightness represents signal level, and color represents signal polarity (green = positive).

4. Gain CV input. Normalized to a constant +8V.

The cornerstones of modular patches

VCAs are absolutely essential in a modular system, for example for:

  • Shaping the amplitude or timbre of a tone with an envelope
  • Animating a mixture of several oscillators
  • Controlling the amount of filter modulation with a random source or a touch controller.
  • Applying an envelope on the linear FM signal hitting an oscillator


  • All inputs DC-coupled.
  • All inputs handle audio-rate signals.
  • Input impedance: 100k for all inputs.
  • Gain scale: a +5V CV translates to a gain of 1 (0dB), both in linear and in exponential mode.
  • Gain range: maximum gain of 2 (+6dB) in linear operation, 10 (+20dB) in exponential operation.

All these hardware description files are released under a cc-by-sa-3.0 license.

Specs & Downloads

Specs & Downloads

100 Modular Addict
HP 12
Depth 25mm
+12V 50mA
-12V 50mA
+5V No
Additional Resources Manual


Customer Reviews (1)

No Fails HereReview by egghead9
First off, great board. The layout is reworked for 603 components, not the microscopic 402s that the original MI board specs. So, make sure you have a 603 BOM (try amazingsynth). Because of the relayout the parts will be in slightly different places than you might expect. However, I found it straightforward to find them. The 603 size of the SMT parts makes it easier, at least for me. A 402 version of the build was the only DIY MI build I failed so far out of 8 builds. Ironically, Fails is a winner! (Posted on 2/25/2018)

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