Amplifier 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.. 

All good @rman9 

I inadvertently hooked up a second preamp output to another devices RCA output.
Our courser the speaker went pretty quiet as one source was driving 0v and the other signal, so you get a voltage divider.

But they are made to do that, or the poutoput impedance would be s closer to 0-ohms, that t50, 500, or #k ohms.

(Probably also why people with high output impedance have more cable effect than ones using a lower output impedance preamp.)

I would not fret, but it is better to ask Luxman as they know their stuff more intimately.

I’ll look forwards to seeing what they tell you.

Can anyone further clarify on this issue? 

This sounds like something I have done in the past. If I am breaking in a new component, say a preamp for example, I wouldn't turn the amplifier on when not listening. I would just let the preamplifier continue to play.  

Similarly my Pass preamp is on all the time while my Pass amplifier is on standby. Is this a potential scenario where the amplifier can become damaged? 

How would one run something out of the tape output? Say for example a headphone amp. You couldn't listen to one over the other without disconnecting? 

An amplifier's input stage can be overloaded by a bad upstream component which has too much voltage. 

A preamp with too many outputs connected may no longer perform correctly as the impedance becomes too low.  It is rare that shorting a preamp (impedance = 0) would cause damage but theoretically possible depending on design.  Usually the output impedance of a preamp is high enough that it is self protecting.