VCA with integrated Decay and Fader/Mixer

Fay combines three functional units in a tiny 4HP module. It consists of a Fader, a VCA and a Decay Envelope.  

If you insert two audio or CV sources into the jacks IN1 and IN2, you may fade between both sources manually using the potentiometer on top. This way you can either mix two waveforms or switch between them.

The signal is directly routed to the VCA. Here you can control the volume or amplitude of the audio or CV signal either manually or via control voltage using the ENV jack.

If there is no cable patched to ENV you will be able to control the VCA with the internal decay envelope. Simply insert a trigger signal into the TRIG jack and use the potentiometer below the LED to control the decay length. The LED indicates the current state of voltage.


● Manual fader/mixer/switch
● Voltage controlled amplifier
● Decay envelope
● Suitable for audio and CV signals
● Full control over volume
● CV attenuator
● LED indication
● VCA control with internal or external CV
● Skiff friendly
● Wrong polarity protection

The module consists of three boards:

● Front PCB Panel
● Control PCB for LEDs, potentiometers and jacks
● Main PCB with all electronic components

More information on

  • 28 mA +12V
  • 17 mA -12V
  • 0 mA 5V
  • 25 mm deep

Module is available as a DIY project only.

This Module is currently available.

submitted Feb 9th 2018, 12:41 by Stobbert | last Change Jan 16th 2019, 04:15 by Stobbert