RO 12V Real-Tube Guitar Preamp PUBLIC

Richter Original 12V Real-Tube Guitar Preamp

Richter Original 12-volt real-tube guitar preamp. Controls Include: Input Level, Fuzz enable switch, Fuzz symmetry switches, Fuzz Depth, Bass, Treble, Drive, and Volume. Based on two proven circuits; the Fender 5E1 Champ (input section) and the Garnet Herzog (output section), together with an output transformer designed to replace that in the Champ. Also includes a shunt-type Schottky-diode array (for fuzz) and a passive 2-band Baxandall tone-control. The design is meant to sound like a boutique single-ended tube-amp, though in a rackmount format, and using only a 12-volt supply voltage. The tubes, one 12U7 dual triode (not 12AU7; do not substitute any other tube, including 12AU7) and one 12AL8 combination triode and tetrode. Both tube types were designed to operate using a single +12VDC supply voltage on plates AND heaters (originally from a car battery). The 12U7 was created to work like a 12AU7 (and should sound like it), but with a 12-vollt supply, while the 12AL8 was purpose-built for use in car radios. Experimental circuitry. Untested design. No simulation. Frequency response and overall gain must be determined during breadboard testing. The tubes are available at The Tube Store. https://www.thetubestore.com . The output transformer is available at DigiKey, part # HM4585-ND. https://www.digikey.com . And the 8-ohm 10W resistor (standing in for a speaker load) is a Dayton DNR-8 wire-wound audio-grade 2%, available at Parts Express, part # OO4-C. https://www.parts-express.com . This circuit was intended as a rackmount project. Do not use any other supply voltage. Example Off-The-Shelf Supply: 12V DC 1000 mA Regulated Switching Power Adapter, Product ID: 798. From the AdaFruit website. https://www.adafruit.com .