by EWBrown » Fri Mar 30, 2007 5:29 am
Seeing your other posting with the voltage checks, it looks like B+ is getting through the OPT primary to the plates and SGs, but for some reason the tubes are not drawing any current.
Possibilities: The EL34s are totally dead (I've rarely seen a bad tube that didn't have some emission, unless the filament was burned out.). Bad socket contacts, or the G1 bias voltage is set too negative. (is -33.3V a normal level?)
When I'm building up a new amp, or fixing an old one, I'll do the initial power tubes' bias setting, with just the rectifier tube and power tubes (EL34s in this case) in place, and adjust the bias as required. After that looks good, I'll insert the remaining river tubes, check again, and then let it burn in a while, then re-check and adjust bias as neded.
/ed B in NH (still waking up and fignhting a cranky computer)
Real Radios Glow in the Dark