RO 12V-Galactic Fuzz Circuit PUBLIC

Richter Original "12V-Galactic Fuzz" With 3-Band Tone

Richter Original "12V-Galactic Fuzz" with 3-band Fender-style tone-stack. Uses one 12V space-charge type twin-triode preamp tube and a shunt-type diode array. Based on preamp section of Epiphone Galaxie 10 guitar amplifier. Controls Include: Input Level, Drive, Fuzz enable switch, Fuzz symmetry switches, Fuzz Depth, Bass, Mid, Treble, and Volume. Specified Tube: 12U7 (not 12AU7), designed for +12VDC supply-voltage on plate AND heater. Do not substitute any other tube (including 12AU7). The 12U7 was also designed to sound like a 12AU7 that is operated at high voltage, though the 12U7 is at +12V (originally provided by a car battery). Available from The Tube Store. https://www.thetubestore.com . For overdriven tube distortion, the input can be overdriven by a boost or overdrive stomp-box while V1 can overdrive V2 depending on setting of the Drive control. Diode Array should not greatly reduce overall gain but will clip the signal (to create fuzz effect). The symmetry switches set the harmonic content of the diode fuzz. Frequency Range 20 Hz to 16 kHz. Suitable for 6/7/8-string guitar or 4/5/6-string bass. Overall Gain +20 dBV (Vo/Vi = 10) with all controls at 50%. Experimental circuitry. Untested design. No simulation available. Build at own risk. Rackmount implementation recommended, with vibration-damping on mounts. And use pads on tube to help mitigate vibrational noise. Power-supply not shown. Requires a regulated single-polarity DC supply providing +12VDC @ >= 200 mA. Example: 12V DC 1000 mA (1A) Regulated Switching Power Adapter, Product ID: 798. $8.95 each. From AdaFruit website. https://www.adafruit.com .