Split-Supply Preamp 3 PUBLIC

Guitar preamp with Fender-style 2-band tone-stack, input tone compensation circuit, and 2-state diode-based fuzz matrix.

Guitar preamp with 3-band Fender-style tone-stack with custom part-values, and 2-state diode-based fuzz matrix. Controls include: Input Level, Input Treble Compensation enable switch, Input Treble Compensation Range switch (3 positions), Input Treble Compensation Adjustment pot; Fuzz enable switch, Fuzz "Clip" pot, Fuzz Type switch (2 selections; Mellow or Bright, each with separate Symmetry switches); Drive; Bass, Mid, Treble, Tone Sum, Gain, and Volume. Specified IC is the TL082 dual op-amp, though any other pin-compatible dual op-amp IC can be used. Suitable for stomp-box or rack-mount applications. The batteries can be replaced by a regulated dual-polarity +-9V DC power-supply capable of 100 mA of current (though circuit should draw less than 20 mA). Preamp accepts signals from passive or active guitar, effects device, another preamp, or guitar processor. Output goes to an amplifier or any other audio gear with a high-impedance input. Gains per frequency with all pots at mid positions, and using a 1V p-p 1 kHz input signal, are; 0dBV @ 20Hz, +23dBV @ 100Hz, +25dBV @ 400Hz, +27dBV @ 1kHz, +30dBV @ 2.5kHz, +27dBV @ 6.3kHz, +19dBV @ 16kHz, and +14dBV @ 20kHz. Though verified, circuit should be considered experimental. Breadboard test before committing to a soldered build.