Experimental MOSFET Fuzz Circuit PUBLIC

Experimental MOSFET Fuzz Circuit for Electric Guitar

Experimental MOSFET fuzz circuit for electric guitar, features one dual FET-input op-amp IC, one CMOS op-amp IC, one hex non-inverting buffer IC that uses MOSFETs internally, and two dual DMOS transistor ICs to provide a complicated method for obtaining fuzz and distortion. Controls Include: Input Gain, Drive, Direct Gain, Direct Send, Bass, MId-Bass, Low-Mid, MId, High-Mid, Treble, MOS Gain, MOS Send, DMOS enable switch, DMOS symmetry switches, DMOS Depth, Output Gain, and Volume. In particular, one FET-input op-amp is used to send a clean input signal to the buffer array and to a Direct Gain Stage in parallel with the buffers. The buffers and Direct Gain Stage can both be overdriven; the buffers giving MOSFET fuzz and the Direct Gain Stage giving CMOS distortion. The signals from the buffers sum in the other clean FET-input op-amp, whose output is itself mixed with the Direct signal in the Output Stage, likewise able to be overdriven to provide even more CMOS distortion. The DMOS (depletion-mode MOSFET) transistors are wired to work like diodes and are used in a hard-clipping (shunt type) array from the Direct signal path to ground, but which can be switches ON or OFF. The buffers are setup as high-pass filters with different low cutoff frequencies. So, they all emphasize highs. But all of the op-amps emphasize lows. And because the filters cut gain significantly, the overall circuit emphasizes lows. Yet, the buffers are for overdriving, not for tone-control, and their differences in low corners is for voicing, not tone shaping. Consequently, using a tone-control of some kind at the input or output of this circuit is recommended. Power-supply not shown. Requires a dual-polarity DC supply providing +-9VDC or +-12VDC or +-15VDC at >= 100 mA of current. And while simulator verified, treat the circuit as experimental in nature. Thus, thoroughly breadboard test before committing to a soldered build. And house in a grounded metal enclosure.