This module is part of my Eurorack series. It’s a voltage controlled amplifier made out of a minimal set of components. It works great in conjunction with an envelope generator and makes your synth sound more natural. There are a lot of applications like shaping different sounds, side-chaining and so on.

Key features

• voltage controlled amplifier
• signal input and output, CV
• gain control
• signal LED
• easy to build, all through hole components
• 4HP

How it works

The heart of the VCA is a long-tailed pair made out of two transistors. It’s a differential amplifier which can be voltage controlled through a third transistor. It has an input and output for the signal and a CV input for controlling the amount of amplification. There is a gain pot which is also controlling the amplification of the VCA.

The kit includes

• all needed quality components
• optionally matched transistor pair

More details and assembly instructions at https://polykit.rocks/vca