Amplifier Damage

@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.

@holmz the integrated that I had swtiched off(Standby), but connected to the unbalanced out of the Active Luxman D03X DAC is the Luxman 550AXII. The balanced out was connected to the Luxman 595ASE which I was listening to. So I dived into the block diagram of the 550AXII, looks like the input signal goes through several gating switches for Tone control, Subsonic control, goes through a buffer before it hits the multi step ladder circuitry of the volume control. All this is in the path before it sees the Preamp circuit. So I am not sure, how far the audio signal goes through when the Unit is in stand by mode. I might call Luxman tomorrow to get more insight into this..