The power supply was described in the section on power supplies. The amplifier and phase splitter is described in the section on phase inverters and drivers and the output section is figure A in the push pull outputs section. The cathode resistor is a 300 ohm 2 watt. Negative feedback is taken from the 16 ohm speaker tap on the output transformer. It goes through the parallel combination of a 3.3 k ohm res and a .001 mike cap to the cathode of the 12 A X 7 stage preceding the phase splitter. The cathode goes to ground through a 100 ohm res. The tone controls work on the fixed tap on the volume control. A 39 k ohm res is in series with a .005 mike cap from the tap to ground. The bass control is a 5 meg ohm pot connected as a rheostat in parallel with the cap. This gives bass boost only, no cut. The wiper of another 5 meg ohm pot, treble control goes to the top of the volume control. The top of the treble pot goes through a 470 pf cap to the tap on the volume control. The bottom of the treble pot goes through a .0033 mike cap to ground. The magnetic phono preamp is the circuit from the Harman Kardon amplifier. End verbal description.