I suspect the title is not terribly clear, so here's the situation:
I am repairing a Luxman L-430 amplifier. It came to me with a blown channel and required several output transistors and an electro cap with a hole in its side replaced. I considered that the electrolytic was the likely culprit and have replaced all electros in the amp as a precaution.
I had it running at up to moderate volumes for several days without trouble (and it sounded very nice).
Source has been a professional CD player with 2V line output, full signal input for the amp is 200mV. This is not ideal but it has been only a minor annoyance with a number of other amps over the last ten years.
Today my partner went to play a CD while I was not home and as she is not used to the new system had not realised that I had turned the amp off earlier (the lamps are all blown and I haven't fixed them at this stage). So without looking she turned the volume up nearly full, realised it was not on and turned it on at full volume. That immediately blew an output device, with just a tiny pop of sound out of the speakers.
That's not the behaviour I would have expected from the amp. I would expect a clipped signal (due to the signal level mis-match) and enough volume to make you wet your pants, but not self destruction.
Am I missing a problem somewhere that higher power may be showing up? Is this actually normal behaviour that I'm unaware of because I don't normally listen at 120dB?
Thoughts are sought, output transistors are a good deal more expensive than fuses and I'd like to rule out doing this frequently.
I am repairing a Luxman L-430 amplifier. It came to me with a blown channel and required several output transistors and an electro cap with a hole in its side replaced. I considered that the electrolytic was the likely culprit and have replaced all electros in the amp as a precaution.
I had it running at up to moderate volumes for several days without trouble (and it sounded very nice).
Source has been a professional CD player with 2V line output, full signal input for the amp is 200mV. This is not ideal but it has been only a minor annoyance with a number of other amps over the last ten years.
Today my partner went to play a CD while I was not home and as she is not used to the new system had not realised that I had turned the amp off earlier (the lamps are all blown and I haven't fixed them at this stage). So without looking she turned the volume up nearly full, realised it was not on and turned it on at full volume. That immediately blew an output device, with just a tiny pop of sound out of the speakers.
That's not the behaviour I would have expected from the amp. I would expect a clipped signal (due to the signal level mis-match) and enough volume to make you wet your pants, but not self destruction.
Am I missing a problem somewhere that higher power may be showing up? Is this actually normal behaviour that I'm unaware of because I don't normally listen at 120dB?
Thoughts are sought, output transistors are a good deal more expensive than fuses and I'd like to rule out doing this frequently.