Born of a need to control the attack of a bass guitar while recording, the Wheeler Leveling Amplifier is loosely based on an old AM radio automatic volume control.

Harold Alden Wheeler invented the automatic volume control circuit in 1925 to balance listening levels among radio stations of varying signal strengths. What’s nice about this type of circuit is that it doesn’t change the shape of the signal peaks (in contrast with a limiter); it just changes the wave amplitude, cycle-by-cycle, delivering a result that’s solid and consistent like a heavily compressed signal but with a timbre that’s true to the input.

A version 2 of this pedal is in the works. In the meantime, putting my Falcon Heavy drive/preamp in front of it accomplishes 90% of what a version 2 design would do, so I’ve just been doing that.

Controls

I (jack) – Input

O – Output

I (knob) – Input gain

PR – Peak reduction ratio

G – Gain (output volume; “G” label like the famous LA-2A leveling amp)