Boost

A circuit that raises level without adding much distortion of its own, used to push an amplifier harder or to lift a solo above the mix.

A clean boost changes level only, which is exactly what a valve amp wants at its input to go from clean to a compressed crunch without the pedal supplying the character. A treble boost does the same thing with a rising frequency response, tightening a dark, overdriven tone and cutting low-end mud, which is the trick behind a lot of classic rock lead sounds. Placement in the chain decides whether the boost also drives the pedals after it.

Example: a clean boost before an already-cranking amp turns a rhythm setting into a lead setting with one stomp and no change in the pedal's own tone.

Boost

See also