Tone stack (original) (raw)

A tone stack is a specialized type of audio filter incorporated into the circuit of an audio amplifier for altering the frequency response of the amplifier. The term is primarily used in reference to instrument amplifiers such as guitar amplifiers. The simplest tone stacks are derived from a bridged T network implemented with resistors in place of inductors, creating a notch filter. These will utilize 3 capacitors and 3 resistors in the form of potentiometers.