Mu-Tron III Envelope Filter

The Mu-Tron III is an envelope-controlled filter that responds to playing dynamics, producing funky, vocal-like wah sounds triggered by pick attack rather than a foot pedal. Jerry Garcia adopted the Mu-Tron III in 1974 and it became central to his tone for the rest of his career, its liquid filter sweeps adding a singing quality to his improvisations on songs like 'Estimated Prophet' and 'Fire on the Mountain.' The circuit's optical sensing element provides smooth, musical tracking that mechanical followers cannot match.