What went bang, smelled of "I'm fried", yet left it in working order...???


Hi gang - wasn't sure if this should go here under amps or tech talk, but here goes: normally, I'd call the salesman I work with at my LAD, but they're closed Sun. & Mon. and I'm loosing sleep over this as I feel I'm on very thin ice.

My wife and I were watching a movie late last night, and after the movie we were sitting on the coach discussing it when we both jumped when we heard a loud bang coming from the media console and smelled an electrical burn. Sitting on top of the console is a Dan D'Agostino Progression Stereo power amp, a McIntosh C53 preamp, and mounted directly behind this on the wall, a Panasonic plasma TV.

Nothing tripped a fuse, the TV was still on, both sets of power meters on both the Dan & Mac were still lit. I streamed a test track that has a lot of bass that when I turn up to a certain volume, has the Dan's power meters hang at 400 watts for a few seconds, and they did - just like always. Everything seems to look and sound fine.

So, while I'm not asking for anyone to try and guess which of those three components made the bang, what I am asking is for any of you here who have an electronics background tell me what electronic part (in either the preamp, amp or TV) possibly could have made a loud bang releasing an electrical burn smell, yet "seemingly" leave everything still functioning as normal...?

--thanks and cheers!

128x128jimmy_jet

Showing 1 response by gs5556

Most likely the power amp varistor. It's got a 2kv transformer with 0.1 Farad power supply capacitance. That shorts a lot of current and the MOV has to be pretty substantial. My guess is what you heard is the MOV cracking under stress. Best to get the amp checked to make sure the fault wasn't internally generated.