1961 Zenith Stereo Amp Problem

[davet753]

The electric company just replaced the transformer on the pole in my back yard a few months ago. The voltage at my outlets is pretty steady at 124 volts. That is a bit high for the design of the amp, but I don't think that those extra 4 volts are enough to cause the B+ to be 30 volts off. The factory service manual says it's designed for 110 to 120 volts.

I know my speakers are good, because I've tried running another set and have the same outcome.

I'm wondering if the fault might be my output tubes. None of the tubes in this set have been replaced (with the exception of my substituting the 5U4 to see if there was any effect on setting the output tube bias). I never placed much stock in tube testers, and got rid of mine years ago, but I do wonder if these original output tubes have good emission levels now.