Do amps have overheat protection?

[Maximilian]

I own a marantz PM6003 stereo amp and it just started putting an audible high pitch noise through the speakers for no reason, so i muted the comp and it was still there so the source must be the amp i thought. I took all the junk off the top of it, turned it off, it felt pretty hot so i left it a while and now its working fine.

Did it overheat? Is that what probably happened? Google turned up nothing about this amp and overheat protection.

 

[Modelworks]

Amplifiers can have temperature protection but how it is implemented is very model specific. Noise when it gets hot is usually caused by failing capacitors. They will eventually fail completely causing either a short doing more damage or total loss of sound.

 

[Ika]

If "pretty hot" is not "painful to touch after a few seconds", I'm not sure it is capacitors - most are rated for at least 60-80C. On my headphone amp, after maybe three or four hours it becomes very uncomfortable to touch longer than a few seconds. I checked with an IR gun, though, and the hottest it gets is about 45C. I don't know about the specific age of that amp, though - older capacitors are more likely to be less tolerant to heat.

Unless you can repeat the high pitched noise consistently after a while I'd look at a problem somewhere else.

 

[Maximilian]

This amp is about 4-5 months old and the temperature wasent too hot to touch but it was significantly hotter than it was before i started to store junk on top of it, the whole top half is one large vent by the looks of it.

Also the high pitch noise could be controlled by the amps volume dial, if that makes any difference to it.