RS-Timbre: MOSFET Fuzz 4 PUBLIC

2-Stage Fuzz Using Dual Depletion-Mode MOSFET ICs

2-stage MOSFET fuzz circuit for electric-guitar. Uses one dual JFET-input op-amp for signal boosting at the input and output, and two dual MOSFET ICs for fuzz. Controls Include: Drive, Gain 1, Gain 2, Intensity, Tone, Output Gain, and Volume. The Input Stage uses one op-amp with fixed gain to drive two MOSFET Fuzz circuits in-series with each other. Fuzz is obtained when the Input Stage overdrives one matched enhancement-mode MOSFET pair which in-turn drives another pair; each pair having adjustable gain. Furthermore, each MOSFET chip is configured to perform as a unity-gain inverting buffer using Zener diodes. This kind of arrangement is known for producing tube-like fuzz. Frequency Range at or above the -3 dBV corners is from 16 Hz to 25 kHz with all controls at 50%. Suitable for 6/7/8-string guitar or 4/5/6-string bass. Example Gains with All Controls at 50%: +16 dBV @ 100 Hz, 14 dBV @ 400 Hz, +15 dBV @ 1 kHz, +17.3 dBV @ 2.5 kHz, and +11 dBV @ 10 kHz, or up to twice these with all controls at 100%. The circuit can be used for stomp-box or rackmount projects. The battery can be replaced by a regulated single-polarity +9V DC supply providing >= 40 mA of current. And though simulator verified, treat the circuit as experimental. Breadboard test before committing to a soldered build.