VCA

A single-channel voltage-controlled amplifier whose response curve sweeps continuously from logarithmic through linear to exponential, a control circuit designed by Osamu Hoshuyama.

Key features

• SHAPE: the response to the incoming CV, swept from logarithmic through linear to exponential
• LEVEL: the output volume, a gain stage after the VCA, to even out the shapes
• OFFSET: opens the VCA by adding a voltage to the CV, for a drone or a bipolar LFO
• CV IN: the attenuator of the CV input, with a lamp that flashes when the CV clips
• A clip lamp on the audio input
• The CV input takes envelopes and LFOs as a VCA, or audio for amplitude modulation
• Three calibration trimmers on the back: BIAS ADJ, OTA OFFSET, CV OFFSET ADJ