BARTOLINI TCT 3-band Tone Control Preamp w/ 300 Hz Mid Cut

The TCT is a tone control module designed for electric guitars, basses and other electronic musical instruments. it yields a very wide range of boost or attenuation of the Bass, Midrange and Treble regions of the musical instrument spectrum. Its tonal range is at least equal to that of that of the older Fender amplifiers with Bass, Treble and Presence (low midrange) controls.

A full explanation and wiring instructions can be found HERE