What would cause this to happen to a preamp?


Yesterday I was at a friends house listening to his system. At one point we noticed that the soundstage shifted left a bit so my friend decided to check the xlr connection to his amp. While the music was still playing, he jiggled the xlr cable at the amp which caused a brief sizzling sound in the preamp. The preamp then shut down. Obviously we were pretty bummed out and concerned. Pushing the power button on the preamp would not power it up. We checked the fuse and it was fine. We then tried disconnecting the power cord and reconnecting it. The preamp then powered up fine. We listened for a few more hours and it sounded fine. So my question is...

Why would "jiggling" the xlr cable at the amp cause the amp to shut down? What happened? Some sort of short?

Thank you...
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Maybe it has a very nervous protection system.

I have used a NAD 310 amp that were so nervous that you couldnt switch a light on without the amps protection circuit kicking in...

DV
We then tried disconnecting the power cord and reconnecting it. The preamp then powered up fine. We listened for a few more hours and it sounded fine
Are we talking about a power cord that connects to the preamp with an IEC connector? If so maybe the cord IEC connector connection was loose and your friend bumped it while messing with the xlr cable. A sizzling sound would be more indicative of a loose 120 volt power connection. Anyway just a thought....
Thanks for the responses. Yes, I am talking about the power cord that connects to the wall and preamp with an IEC connector. The cord is no where near where the amp is so I do not think that my friend touched it.

I wonder if the XLR is defective somehow. Maybe by jiggling it he caused a short of some kind???? Seems strange to me the just jiggling the IC would have an affect like this unless a short was caused....
In your description, you talk about the preamp shutting down AND you talk about the amp shutting down too. I'm a bit confused. Did they both shut down?
nsgarch, the amps are connected to the preamp via a trigger.
If it's not a "nervous protection circuit" as Dewald mentioned, then something like an intermittent short (or even an intermittent open circuit) in the IC is overloading the preamp and causing it to shut down. At least those are the only two EXTERNAL reasons (that I can think of ;--)
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