PEDAL BENCH
by Stompbox Labs
← All pedals
Fuzz1968· Shin-ei (Japan, OEMed by Univox)

Univox Super-Fuzz

Octave-up two-transistor fuzz with the meanest 'ring' in rock — Pete Townshend's secret sauce.

⏳
Schematic pending verification

We don't ship reference schematics until they've been hand-authored against authoritative sources (manufacturer service docs, ElectroSmash analyses, GEOFEX writeups) and reviewed in the simulator. Until then, the BOM, signal chain, controls and mod notes below are accurate, and you can still add this pedal to a project — it just won't include a circuit yet.

About

Two NPN silicon transistor gain stages drive a balanced-pair / transformer-style full-wave rectifier circuit, producing aggressive octave-up doubling on top of monstrous square-wave fuzz. The 'Tone' switch notches mids out for that classic scooped Super-Fuzz roar.

Signal chain preview

5 stages
Input
Q1 common-emitter NPN gain stage
Q2 common-emitter NPN gain stage
Differential / balanced pair (Q3, Q4) for full-wave rectification → octave-up content
Diode clipping to ground for square-wave fuzz
Tone switch (mid-scoop on / flat off) and Volume
Output

Quick facts

  • Used by Pete Townshend, J Mascis, and Mudhoney (the '''f' word' that defined grunge).
  • Shin-ei built it in Japan; Univox / Honey / Apollo / Companion sold rebadged versions.
  • The octave-up effect comes from full-wave rectification of the differential pair, not from a separate octave circuit.

Controls

  • Expander (volume)
  • Balance (gain)
  • Tone switch (2-position)

Mod recipes Pro

3 mods
  • Bias trim

    Tame the gating and dial in the octave content.

    How: Replace the fixed bias resistor on Q3/Q4 with a 100k trim pot; tune for maximum octave clarity at unity volume.

  • Germanium clippers

    Smoother, less buzzy clip.

    How: Swap the silicon clipping diodes for OA91 / 1N34A germaniums — drops the clipping threshold and rounds the square wave.

  • True bypass + LED

    Modernize the chassis without altering the circuit.

    How: Rewire the input/output and power through a 3PDT footswitch with an indicator LED + current-limiting resistor.

References