Split-Supply Preamp 2 PUBLIC

Split-Supply Guitar Preamp with 3-Band Tone and Diode Fuzz.

Split-supply high-gain guitar preamp with Fender-style 3-band tone-stack and Schottky-diode fuzz. Controls Include: Input Attenuation enable switch (Attenuate or Direct), Attenuation control, Fuzz enable switch, Fuzz symmetry switches (two with 2 settings each), Fuzz Depth, Drive, Bass, Mid, Treble, Stack-Sum, Gain, and Volume. Maximum gain with all controls at 50% is +19.4 dBV @ 325 Hz, or +44.3 dBV @ 1 kHz with all controls at 100%. Thus, with fuzz off, the circuit will serve as a 2-stage Clean Boost and/or Preamp with 3-band tone. The fuzz is from Schottky diodes which sound like germanium diodes but with a more "fuzzy" character. Frequency range with all controls at 50% is from 38 Hz to 25 kHz. Suitable for 6/7-string guitar or 4-string bass, with emphasis on highs (not recommended for 8-string guitars or 5/6-string bass). Two battery power-supply is shown (for stomp-box project) but the batteries can be replaced by a regulated dual-polarity DC supply providing +-9VDC or +-12VDC or +-15VDC at >= 20 mA of current (for rackmount project). And though simulator verified, treat the circuit as experimental. Breadboard test it before soldering.