My brother and I have build a preamplifier with 6H30 double triode in SRPP mode. We have chosen the same design we used in our tuner as we like the sound of this amplifier. We decided to use an Alps motor potentiometer as volume control.
Note that you have to use a Sony compatible remote control with the preamplifier.
Update! We have designed and built a new add-on pcb to eliminate volume potentiometer moving in notch when you press and hold volume up or down continuously, a very nice modifcation. The add-on pcb replace the old motor control pcb and you will also have to re-program and move the 18F452 PIC to the new add-on pcb.
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Add-on pcb with all components mounted. Connects to the pic pcb through two IC sockets: the old 18F452 and one of the ULN2803!