Well, it was the burnt-out 10 ohm resistor. Clearly a regular occurance in the life of this amp as other sockets had these resistors changed as well. The amps are running fine now...I think. One more question for the fellow sufferers - what bias do you run them at? I don't think I hear a difference between 440 mV and 490 mV. What has been your experience with tube life in these units ? Should one expect longer life at 400 mV than 490 mV ?
Thanks for your comments !
Thanks for your comments !