What is a VCA?

VCA stands for Voltage Controlled Amplifier. It lets you control the volume of a signal using control voltage. Simple in concept, but incredibly flexible — VCAs aren't just for audio, they're for shaping any signal dynamically.

You’ll often find them paired with envelopes to control how a sound fades in and out. But they also work with LFOs, random sources, and more to modulate signals over time.

Common Uses

• Audio: Control the amplitude of your oscillator signal. Essential for making plucks, pads, and anything with dynamic shape.
• Modulation: Use a VCA to control how much modulation is applied — modulate your modulation.
• CV Routing: VCAs act as switches or gates for control voltages. Want to turn an LFO on and off? VCA.

Types of VCAs

• Linear: Good for CV and modulation signals — scales evenly.
• Exponential: Feels more natural to the human ear — better for audio dynamics.
• Dual / Quad / Mixed VCAs: Common in Eurorack for space-saving. Some offer both linear and exponential modes.

VCAs are essential. You might not think about them much, but if you want your patch to evolve, breathe, pulse, or fade — the VCA is doing the heavy lifting. Modular wisdom: you can never have too many VCAs.