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Fuzz1966· Dallas Arbiter (UK)

Dallas Arbiter Fuzz Face

Two-transistor germanium fuzz — Hendrix in a smiley-face enclosure.

⏳
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

A direct-coupled two-transistor amplifier (Q1 common-emitter, Q2 emitter follower with collector feedback to Q1's base) that overloads its own gain stage to produce thick, octave-tinged fuzz. Cleans up beautifully with guitar volume — a hallmark of the circuit.

Signal chain preview

6 stages
Input
Input cap to Q1 base
Q1 common-emitter stage (no emitter resistor for max gain)
Direct coupling to Q2 base
Q2 emitter follower; collector feedback resistor sets Q1 bias
Fuzz pot at Q2 emitter (varies degeneration)
Volume pot at output
Output

Quick facts

  • Only two transistors and a handful of parts — one of the simplest fuzz circuits ever.
  • Original germanium NKT275 transistors require hand-matching for gain (hFE ~70 and ~120).
  • Loves a humbucker straight in — buffered pedals before it kill the interaction.
  • Silicon BC108/BC109 versions (later '60s) sound brighter and more aggressive.

Controls

  • Fuzz (1k linear pot)
  • Volume (500k log pot)

Mod recipes Pro

4 mods
  • Sun Face germanium build

    Authentic Hendrix-era warmth using NOS germanium transistors.

    How: Substitute Q1/Q2 with matched germanium AC128 or NKT275 (hFE 70-110 for Q1, 110-150 for Q2). Reverse PSU polarity to positive-ground.

  • Bias trim pot

    Tune the bias to compensate for transistor variation and temperature drift.

    How: Replace R4 (10kΩ collector resistor on Q2) with a 20kΩ trim pot in series with 4.7kΩ. Adjust until Q2 collector reads -4.5V (negative ground) or +4.5V (positive ground).

  • Pre-gain pot

    Recover the classic 'guitar volume cleanup' trick without rolling off your guitar volume.

    How: Insert a 1MΩ audio pot between input jack tip and C1. Acts as a passive pre-gain control.

  • Silicon for stability

    More consistent build, less temperature-dependent, fatter low end.

    How: Use BC108C or 2N3904 (negative ground). Adjust R3 from 33kΩ down to ~10kΩ to compensate for silicon's higher gain.

References

Community-sourced (ElectroSmash, R.G. Keen / GEOFEX). Germanium transistors require matched gain and leakage measurements.