PEDAL BENCH
by Stompbox Labs
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Distortion1978· Boss / Roland (Japan)

Boss DS-1 Distortion

Asymmetric op-amp distortion — bright, cutting, and on every pro pedalboard at some point.

⏳
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 transistor input boost feeds an op-amp gain stage, after which an asymmetric trio of clipping diodes (two in one direction, one in the other) creates DS-1's bright, asymmetric distortion. A two-band-ish active tone control follows.

Signal chain preview

5 stages
Input
Q1: 2SC732 input transistor booster
Op-amp non-inverting gain stage (Toshiba TA7136AP originally, or 4558)
Asymmetric clipping diodes to ground (2× 1N4148 + 1× 1N4148 opposite)
Active tone control (treble + bass via gyrator)
Output level pot + Q2 output buffer
Output

Quick facts

  • Asymmetric clipping = mild 2nd-harmonic content, more 'amp-like' than fully symmetric.
  • The tone stack is an active gyrator-style mid-cut — very different from a TS-style mid-hump.
  • Used by Joe Satriani, Steve Vai (early), and Kurt Cobain (Bleach/Nevermind era).
  • Famous mod: 'Keeley Mod' swaps clipping diodes and a few caps for more bass + warmer tone.

Controls

  • Tone (20k linear)
  • Level (100k log)
  • Dist (100k log)

References