Amplifier Damage


Had a question, can an amplifier's input stages be hurt, driving an audio signal through it while it is in Stand By/Powered down. The reason I am asking is I have two integrated amps hooked up to the DAC, one to the unbalanced out and the other balanced out. The one hooked up to the Unbalanced out was powered down while I was listening to the one hooked up to the balanced out for several hours. 

Once I realized that, I disconnected the Amp powered off, Everything seems to work fine, but I had the nagging question. Does the input audio signal get shunted to ground through a diode in the input amp stages when its powered off or something to protect the circuitry? 

Any inputs will be great

rman9

@rman9

Amps are weird in that things can go wrong even whilst they’re not doing much.

All it would take is for just one component to fail...

It’s extremely rare, but not impossible.

 

However, in your case I don’t think there’s anything to worry about as the all important heat generating circuits were switched off. And even if they weren't, so what?

 

The general consensus seems to be that’s it better to leave your amp on rather than to keep powering it on and off.

 

Unless you’re talking heat generating Class A designs - or tubes.

With those you’d probably be better off powering them up for the listening duration only.

 

In any case, it’s just one of those things not worth worrying about when you want to immerse yourself in the music.

A bit like a meteorite hitting your house or Yellowstone Park erupting at an inopportune moment.

If it happens, it happens.

No point in worrying about such infinitely remote possibilities when your seeking pure sonic pleasure.

@cd318 loved reading your response.. The last four sentences are the best and typically I try to lead my life 😊 that way.. too much seriousness would lead to health issues anyways.. 

Coincidentally, both Amps are Class A.. But again, no damage done.. So I'll move on and enjoy the music.. Thanks again..  

Sorry but you should not do that, it should be fully disconnected, not just off. The preamp is seeing the idle amp as a load. Sometimes OK sometimes not.

@russ69 Thank you!! it was accidental.. I am usually careful with things like this.. But it was a miss yesterday.. Hopefully it's not a permanent damage.. 

fine, but I had the nagging question. Does the input audio signal get shunted to ground through a diode in the input amp stages when its powered off or something to protect the circuitry? 

Any inputs will be great

With a DMM one could measure the input impedance with the amp on and off.
I have never heard of an amp shunting the input to ground.
Even if it did the output impedance of the DAC or preamp would mean that the DAC would not suffer,

Subjectively one would hear the level drop if the amp that was powered off was shunted to ground. And we never hear that.