Usually three 100K linear pots for Volume , Sustain (gain), and Tone . 3. Popular Schematic Variations

Because the circuit has evolved since 1969, enthusiasts often choose a specific "era" to clone:

Historically high-gain silicon NPN types like 2N5088 , BC239 , or SE4010 . Diodes: Standard silicon diodes (e.g., 1N4148).

The "heart" of the Muff sound. Two nearly identical stages use silicon diodes (often 1N4148 or 1N914) in feedback loops to "soft clip" the signal twice. This dual-stage clipping creates the characteristic long sustain and heavy compression.