As the title says I want to know your views on this: I have a receiver which requires 220 volts DC HT for the valve anodes and 12.6 volts DC for the heaters from a seperate PSU at the moment I have it run via a variac fed from an isolation TX the unfortunate thing is its audio output is a bit on the low side so I want to run it through an audio amplifier the thing is the amp has the mains neutral straight to chassis and one side of AF input also to the chassis so if I link the 2 beasts together my receiver RF Earth will also be taking the amps chassis to earth I could run it all from the isolation TX do you think that's the best option?
OK so it sounds like the receiver, LT and HT supply are all OK, at least when operating in isolation,and the 3 wire feed means the common ground thing cannot be wrong at the receiver end. It is still possible that the LT supply has an unwanted connection between the primary side and the output that does not affect normal operation.
Have you opened the failed LT PSU to see where the 'magic smoke' has come from ?
Also to the audio output from this radio - is there an audio output transformer that is isolated between primary and secondary, or is it capacitor coupled from an anode load for example ? (and if so, is it man enough for the voltages now upon it.)
And at the other end, is the audio amplifier input directly coupled, and to what ? If it is designed for a high impedance input, there may be DC bias voltages you do not wish to load,and capacitivy coupling may be in order.
Do you have circuit diagrams (or are they on the internet ?)
