Tommorrow I would call Cary in the AM. Phenomenal customer service and can troubleshoot may things over the phone with you.
2 responses Add your response
Thanks for your suggestion. I called and spoke to Gerald Walsh at Cary, who suggested a method of tube-switching that established quickly I had a faulty pre-driver tube (one of an NOS pair I'd just gotten) when the thunk sound traveled to the left channel when I switched the tube from the right to the left side of the amp. I subsequently learned from Gerald that a faulty pre-driver could send too much current to the powertube, which would cause the red flash I saw in the far right EL34 in conjunction with the thunk sound and silence that followed. It still is a mystery why the channel went dead, as Gerald said there is no single-channel auto-mute function but that the muting should work on both channels simultaneously. There was some concern these instances might be causing damage to the capacitors or resistors, but, after changing pre-drivers this morning, all seems functioning normally. Thanks for your suggestion, which eventually turned up the cause of the problems.