David McGown wrote:
Suggestion...Use a NTC thermistor on the transformer secondary or after the rectifier. It will limit the current (and get plenty hot in the process), but will cut back to a few ohms of resistance once it warms up. You can use a time delay relay to bypass it if you want.
David
There is a relay in the DC part of the secondary circuit (yes with a diode across the terminals in the reverse direction). There is a 100K 3 watt resistor across it. I wrongly figured that would make the load on resistors and diodes in the circuit safe. There is 30-40 volts on the B+ circuit, after the relay, when the contacts close. The resistors fail after the contacts close.
My B+ is marginally low as it is. There would definitely need to be a relay across the thermistor to keep voltage up.
The other amp, identical to this one, has been operating without issue for many, many hours at this point.
However, starting from scratch on the next amp, the thermistor route may be the one followed!
Thanks!
Stuart