Colorsound Power Boost

The Colorsound Power Boost is a British boost and overdrive pedal from the late 1960s, built around a simple three-transistor preamp with a two-band Baxandall EQ¹. It was designed to be a clean, high-headroom booster that pushed the front end of a guitar amp into natural overdrive², and it ran at 18 volts from two 9V batteries, which gave it far more output than most pedals of its day³⁴.

It was created around 1968 by Gary Hurst¹ and released by Sola Sound, the London company behind the Tone Bender¹⁵⁶. Players know it best through David Gilmour, who used it extensively during the 1970s, and Jeff Beck, who used it for what Tru-Fi calls a "thick, explosive lead tone"⁶³². Production of the 18V version ended in 1971, when Colorsound revised it into the 9V Overdriver⁷⁸⁴.

What it does to your sound

The Power Boost was designed as a clean, high-headroom booster meant to drive an amplifier's input harder, producing overdrive from the amp itself rather than from the pedal². Its two-band Baxandall EQ lets you shape bass and treble independently, a feature carried over from hi-fi preamp design and unusual on a pedal of this era¹.

One quirk matters to anyone playing an original or an accurate clone: on the original, the pot labeled Volume behaves more as a gain control than a true volume control⁹. There was no master volume, so the pedal's output level rose with its gain setting.

Power: 18 volts

The Power Boost ran at 18 volts, supplied by two 9V batteries in series³⁴. That doubled voltage is the heart of the pedal's character: it is what gave the circuit its high headroom and its very large boost factor.

It is also why the pedal gained a reputation for being too loud. Tru-Fi is blunt about it⁸⁴:

Colorsound later added a master volume mod, letting a player max the gain and control the output level separately⁴. DIY builders commonly make the same change: Tagboardeffects published four stripboard layouts of the circuit, two identical to the original early and late versions and two with an added master volume pot, precisely so a builder can run full gain and set the level independently⁹.

Who designed it, and where it came from

The circuit is credited to Gary Hurst, created around 1968¹. Sola Sound, the London company behind the Tone Bender, released it in 1969⁶, and it was first sold in 1970 through the Macaris music store in London³. Premier Guitar's history of the Tone Bender notes the Power Boost was added to the Colorsound line alongside another three-transistor fuzz¹⁰.

The release date is genuinely disputed. Tru-Fi says 1969⁶, Aion FX's research says it was first sold in 1970 and notes that Macari's own website claims 1968, while Kit Rae's research dates the Colorsound brand itself to 1970, which Aion FX finds more trustworthy³¹¹¹. With no ruling between them, the honest answer is 1968 to 1970 depending on whose account you read.

The original units came in a distinctive orange enclosure, though later versions appeared in different colors, some with slight modifications to the circuitry or controls². Aion FX identifies at least two circuit variants, an early version and a later version with a few different parts between them³¹¹.

The Power Boost and the Overdriver

For a player comparing the two today, the practical differences are the power supply (18V versus 9V) and the tamed output. Vintage Power Boost units are sought after by collectors and enthusiasts².

Who used it

• David Gilmour used the Power Boost extensively during the 1970s, an association Tru-Fi links to his iconic tones of that era². RockBoard's PedalPedia lists Gilmour among the pros whose 70s signature tones relied on it¹².
• Jeff Beck used it for a thick, explosive lead tone⁶, and Pedal of the Day names him alongside Gilmour as a favorite of the pedal⁶¹³.

Clones and modern versions

The original's popularity has produced reissues and clones from various manufacturers². A few the press has covered:

For DIY builders, Tagboardeffects published verified stripboard layouts in 2017 covering the early and late versions plus the master volume mods⁹. One builder reported that the drive bunched up at the end of the pot and fixed it by swapping the 10k volume pot for a 1k, and that after trying the circuit at 18 volts he actually preferred it at 9 volts⁹.

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