VCA

VCA stands for Voltage Controlled Amplifier, a circuit used in compressors, tremolos, gates, phasers, and boosts¹. VCA compressors are known for being fast, clean, and transparent, thickening single notes without thumping and making chords gel together²¹. VCA tremolo is described as a little less contoured than Fender optical or bias tremolo, but easy to regulate and ideal for precise, choppy, and fast modulations³. Unlike optical and VCA-based designs, which attenuate the signal itself, bias tremolo works by varying the bias voltage applied to an amplifier's power tubes⁴. Specific designs include Blackmer VCAs, used in compressors and noise gates⁵⁶.