Tone control circuit diagrams

Amp with Tone Controls & Soft Switching

Built around an LM380, this amplifier includes tone controls and electronic "soft switching". The soft switching circuitry ensures power is built up gradually eliminating the dc thump.

Loudness Control

When listening to music at low volume levels, bass and treble frequencies are attenuated more than mid frequencies. This loudness control alters the frequency response curve to correspond roughly with the equal loudness characteristic of the ear. The circuit shown, is for a single channel, so for a stereo system, two such units should be built. This circuit has a boost of 13dB at 20Hz and approximately 9dB at 20kHz.

Audio Notch Filter

A variable notch filter with both high and low pass filters.

Sound Modifier

Four shape-controls portable unit. Wide variety of output waveforms

3 Band Equalizer

A tone control circuit made with a single op-amp and having three ranges, bass, middle and treble controls.

Tremolo Effect Generator

Stand-alone, 9V battery powered unit. High overload margin, low distortion circuit

Guitar Preamp with Tone Controls

An electric guitar pre-amp with tone controls using dual supplies. The guitar pickup is high impedance, therefore good quality screened cable must be used between guitar pickup and the preamp.

Tone Control

Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of around 6dB at 10K and 50Hz.