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by Stompbox Labs
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Boost1965· Dallas Musical (UK)

Dallas Rangemaster Treble Booster

Single-transistor germanium treble boost — Brian May, Tony Iommi, Clapton's 'Beano' tone.

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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 single OC44 PNP germanium transistor in a high-pass-filtered common-emitter stage. The input cap (~5 nF) attenuates everything below ~750 Hz, so the boost slams the amp's front end only with upper-mid and treble content — turning a darker amp into a singing, midrange-rich beast.

Signal chain preview

4 stages
Input
Input cap (~5 nF — high-pass at ~750 Hz)
Q1 PNP germanium common-emitter gain stage (~+20 to +28 dB)
Output volume pot
Positive-ground 9 V supply
Output

Quick facts

  • Brian May's entire 'Queen' guitar tone is a Rangemaster into a cranked AC30.
  • Eric Clapton's 'Beano' Bluesbreaker tone (Clapton with John Mayall, 1966) is widely credited to a Rangemaster.
  • Was a desktop unit, not a stompbox — players left it always-on, on top of their amp.

Controls

  • Volume / Boost (10k audio)

Mod recipes Pro

3 mods
  • Full-range mod

    Flips it into a flat boost like an LPB-1.

    How: Replace C1 (5 nF) with 0.1 µF — the high-pass corner moves down to ~16 Hz and you get the full guitar range.

  • Mid-boost option

    A switchable mid-focused setting.

    How: Wire an SPDT switch selecting between 5 nF (treble), 22 nF (mid), and 0.1 µF (full-range) for C1.

  • Silicon swap

    Consistency at the cost of warmth.

    How: Replace OC44 with a 2N3906 (PNP silicon). Drop the bias resistor from 68k to 47k to compensate for silicon's higher gain.

References