RO MOSdistort Guitar Preamp PUBLIC

Richter Original MOSdistort Guitar Preamp w. 2-Band Tone

Richter Original MOSdistort guitar preamp using FET-input op-amps along with two discrete MOSFETs, and a 2-band active Baxandall tone circuit. Controls Include: Gain, Drive, Bass, Treble, Intensity, and Volume. The specified op-amp IC was chosen to ensure clean op-amp operation at all control settings while the MOSFETs are for overdriving. If op-amp distortion is desired in addition to MOSFET distortion, consider the following substitutions for the op-amp IC. For JFET distortion, use the TL082CP. For more MOSFET distortion, use the OPA2156IDR. For tube-like BJT distortion, use the NJM5532M (Japanese version of the NE5532N). [Note: Each such substitution will involve increased noise.] Frequency Range 38 Hz to 25 kHz with all controls at 50%, or 16 Hz to 160 kHz with all controls at 100%. Suitable for 6/7/8-string guitar or 4/5/6-string bass. Peak frequency shifts higher when all controls are set > 50%. Maximum Gain = +20.4 dBV @ 630 Hz with all controls at 50%, or +73.8 dBV @ 2.5 kHz with all controls at 100%. Battery shown indicates +12.7 VDC as the power-supply. The battery can be replaced by a regulated single-polarity DC supply providing +12VDC @ >= 50 mA of current. Rackmount implementation is recommended. And though simulator verified, treat the circuit as experimental. Breadboard test before committing to a soldered build. Note: This design is expected to sound like a vintage tube-type guitar-amp.