5-Bandpass Tone Circuit for Guitar PUBLIC

5-Bandpass Tone Circuit for Guitar.

Tone-control circuit using 5 passive bandpass filters driven by an op-amp input stage and whose signals are summed in an op-amp output stage. Controls include; Input Level, Drive, 5 tone pots, and Volume. Bands are labeled Treble, High-Mid, Mid, Low-Mid, and Bass. Band high and low corners are shown in diagram. Total circuit gains per frequency with all pots at middle positions, and using 1 V p-p 1 kHz input signal, are; -13dBV @ 40Hz, 0dBV @ 63Hz, +5.5dBV @ 82Hz, +11dBV @ 100Hz, +22dBV @ 250Hz, +24dBV from 400Hz to 630Hz, +22dBV @ 1kHz, +15dBV @ 2.5Hz, +9.3dBV @ 4kHz, +4dBV @ 6.3kHz, 0dBV @ 9kHz, +1.3dBV @ 10kHz, -7dBV @ 15kHz, and -9dBV @ 20kHz. Absolute maximum possible total circuit gain = +48dBV from 400Hz to 630Hz. Thus, circuit emphasizes mids between 100Hz and 4kHz. Ideal for enhancing the natural notes of a 6-string electric guitar. Suitable for stomp-box or rack-mount applications. Batteries can be replaced by a regulated dual-polarity +-9V DC power-supply providing 50 mA to 100 mA of available current. Though verified, treat circuit as experimental. Breadboard test before committing to soldered build. House completed project in a grounded metal enclosure.