High-Gain 3-Band EQ w. Fuzz PUBLIC

High-Gain 3-Band EQ with Diode Fuzz

High-gain 3-band EQ circuit with optional diode fuzz and mixable input signal. Controls Include: Input Gain, Drive, Driver Gain, Direct Send, Fuzz enable switch, Fuzz symmetry switches, Fuzz Depth, Low Level, Mid Level, High Level, and Master volume. The three EQ bands are from separate active filters using low-noise op-amps. The high / low crossover frequency is 1 kHz, and the mid center-frequency is 1.6 kHz. Total circuit frequency range is from 40 Hz to 40 kHz with all controls at 50%. Maximum gain = +33 dBV @ 1.6 kHz with all controls at 50%, and twice that with all controls at 100%. Designed for 6-string electric guitar (not recommended for 7/8-string guitar or bass-guitar). Power-supply not shown. Requires a regulated dual-polarity DC supply providing +-9VDC or +-12VDC or +-15VDC at >= 80 mA of current. And while simulator verified, treat the circuit as experimental. Breadboard test before soldering. Note: ICs chosen to ensure clean operation. For overdriven op-amp distortion in addition to the fuzz, keep IC1 as is but substitute IC2, IC3, and/or IC4 with one of the following. The OPA2156IDR dual CMOS op-amp IC provides acceptable MOSFET distortion. The NJM5532M dual BJT op-amp IC provides tube-like distortion (similar to that of a 12AX7 preamp tube). However, such substitutions will come with increased noise. Perform listening tests while breadboarding to determine if noise from either of these choices is unacceptably high.