RO Experimental Real-Tube Preamp PUBLIC

Richter Original Experimental Real-Tube Preamp Circuit

Richter Original experimental real-tube guitar preamp circuit. Controls Include: Bass, Mid-Center, Treble, Drive, Fuzz, Output Tone, Intensity, Feedback (FB), and Volume. Employs one 12U7 dual triode (not a 12AU7; do not substitute with 12AU7; no equivalent substitute available) and two 6AK5W pentodes (equivalent to 5654W; these are not beam-power tubes). The 12U7 was originally designed for car radios using a +12VDC supply for both plate and heater voltages, while the 6AK7W was designed for normal tube-supply voltages but will work with a +12VDC supply (though limited in performance). Both tube types are available online at https://www.amplifiedparts.com . Note that this circuit is not intended to provide much gain but just tube-type fuzz/distortion. HIgher gain can be realized by driving the input with an overdrive stomp-box. Recommend rack-mount implementation, with vibration-damping mountings. Completely experimental and untested design, though based on proven circuits.
Original Circuit Sources: https://circuitstream.blogspot.com and https://groupdiy.com .
Power-supply not shown. Requires a well-filtered or regulated single-polarity DC supply providing +12VDC @ >= 500 mA of current. House project in a grounded metal enclosure. No guarantee is implied, and no simulation results are available. Breadboard testing required. Build at your own risk.