RO 12V 6W MOSFET Power-Amp PUBLIC

Richter Original 12-Volt 6-Watt Power-Amplifier for Guitar

Richter Original 12-volt 6-watt power-amplifier for electric guitar. Controls Include: High-Cut, Tone, and Volume. Provides 6W RMS into an 8-ohm or 4-ohm speaker. An example 15 W speaker is noted in the diagram, along with part numbers for the ICs, MOSFET, and Transformer. This is a single-ended design using a MOSFET instead of a tube, and op-amps instead of preamp tubes or discrete transistors. IC1 was chosen to ensure clean operation of the Input Stage and Tone Stage at all control settings, but IC2 is a BJT op-amp which could be overdriven to obtain op-distortion in addition to the MOSFET sound. And a transformer is included to get its sound since much of the sound of a power-amp comes from the output transformer, if used. Thus, it is expected that this circuit will sound much like a low-wattage single-ended tube-type practice-amp. An off-the-shelf power-supply is also specified, to replace the 12V battery shown in the diagram. Frequency Range 12 Hz to 10 kHz with all controls at 50%, or 10 Hz to 10 kHz with the High-Cut and Volume controls at 100% (the High-Cut control's arrow is oriented opposite to the effect of control, so gain increases with clockwise rotation). Maximum Gain = +25.6 dBV @ 160 Hz with all controls at 50%, or +33 dBV with High-Cut and Volume controls at 100%. Experimental circuitry. Full Disclosure: Design completed with contributions from CircuitLab's AI Assistant, which recommended thorough breadboard testing before committing to a soldered build. Helpful Hint: As this is an untested design, obtain several IC2s and MOSFETs to have plenty on-hand during breadboard testing. Once testing is complete, the spare op-amp in IC2 will be available for additional circuitry, Otherwise, leave it unused (ground the + input).