This circuit is based on the earliest version of the Colorsound Power Boost, made famous by artists such as Jeff Beck and David Gilmour. The Power Boost was designed by Gary Hurst in the late 1960s and sold by Macari’s Musical Exchange in London, UK.
This pedal can be run via a standard 2.1mm negative tip power supply of 9-18v (with 18v providing the most headroom and output).
Please note that due to the amount of available gain / output of this circuit, the pedal may oscillate and pick up RF interference if the treble and output controls are turned right up at the same time!
Middle knob = output
Left knob = bass
Right knob = treble