Isolate amp or stack

Miller thanks for your response. I know where you're coming from with your opinions on HT. Personally I see it as a different aspect of sound reproduction. You could argue that you are not looking for the highest in highest of sound quality. You might argue that you are looking more for channel separation, speech clarity, bass response and chest slam... ie terms that you would not talk about in the 2 channel music reproduction aspect. You're also going to be able to argue that a well put together system should sound excellent and cohesive. There is overlap after all since it's just sound reproduction. In only case I don't agree that a HT enthusiast should just be written off as not caring about sound quality. Maybe they are just looking to improve their system and recreate a good theater experience for which different aspects still need to be considered. I still would not want to hear my speakers hum during a quiet passage in a movie. 

Maybe I should specify the question for both music and theater reproduction? If anything you've answered the one already. Thank you. 

Several different things going on here all being conflated and confused and rolled into one. Fields are a whole thing and I rather doubt you are going to wrap each component in a Faraday cage. So what you need to know, it depends greatly on the component. 

Phono stages are most susceptible. Because of the incredible gain even the tiniest noise becomes obvious and annoying. With power amps, the line level coming in is a thousand times greater and so it matters much less.  

But with amps it still matters what we're talking about. Sub amps are pretty much immune. Not because of the amp but because of our hearing. We just don't notice nearly as much. Everything up from there however vibration control is huge. 

Yes you can stack amps. My system is a good example. Notice the sub amps are stacked, they never get hot and with them it does not matter. My integrated amp however has massive vibration control- granite, BDR, and Townshend Pods. Notice my phono stage is isolated with massive rack, BDR and Townshend Pods, as well as being physically isolated by distance from electromagnetic fields.  https://systems.audiogon.com/systems/8367 

Your best solution is Townshend Pods under every component. Since you are doing multi-channel then you are talking home theater and it is hard to see why it matters, HT being a wasteland of bad sound. Stack the sub, surround, and center channel, and put the stereo amps on Pods. This will help a lot. But honestly, if you really are concerned with sound quality the answer is fewer amps and channels. 

If you stack you should use very good isolation such as MAGICO Q PODS or GALLA feet however it is always better for sonics to use 2 stands.