I have a schematic. There are three versions but very little difference between them. Last version (dated 6-18-82) shows a couple of caps added to the +15 regulator. The second version (not dated) shows a change to the Master Volume circuit. The signal passes through one CMOS gate in the preamp and one in the power amp. The CMOS runs off of a +/- 4 volt regulator generated by a couple of Op-Amps which get a reference voltage from the unregulated -45 so it will have some sag to it.