"Amplifier Noise Floor" and hum acceptable?


I recently purchased the Parasound A52+ (5 channel amplifier, 180 wpc all ch driven). Initially I loved it and had no issues. About 2 weeks in however I was sitting around quietly and noticed the dreaded 60 hz hum. I get up close to the speaker midrange driver (Focal Aria 936) and there it is blaring at me. It is present in all 5 speakers I have connected. Everything is connected on a single dedicated receptacle with a power conditioner.

Trouble shooting.. the hum is not affected by volume control on the preamp. When I have removed the XLR cables to the preamp and ONLY have the speaker cables and the power cable connected... it hums. I did recently change my receptacle from a stock to a Hubbell but I don't think this would affect it. I upgraded my power conditioner too to see if that would do anything (I didn't think it would) and it did not. I switched the parasound out for a class D amp (120 wpc) and there was almost no hum. I switched it out for another class AB amp (140 wpc) and there was a hum but about half the volume of the parasound. 

So here's the gist.. when I emailed parasound tech support there are 2 things he said that I thought were noteworthy. One, he states that it is typical and normal to have some hum that close to the speaker baffle, i.e. within 1 foot of it. Second, while I asked for help he ultimately just said "I think you are just hearing the amplifier noise floor".

Three questions I pose to the community. 
Is it normal to hear a hum next to your speak baffle?
Is it acceptable and normal to be hearing the "amplifier noise floor"?
What can I try to lower this noise floor? I thought about connecting a ground wire between the chassis of the A52 and my power conditioner as the next step...

Thanks in advance for input.
jwl244
"I did recently change my receptacle from a stock to a Hubbell but I don't think this would affect it."
Did you notice the hum before you changed to the Hubbell?  
https://parasound.com/a52+.php

Based on the specs linked above, there is absolutely no way you should be hearing hum a foot away, even despite your speakers higher than average sensitivity. A slight hiss with your ear to the tweeter is the most you should hear.

I had a similar issue with the Halo Integrated, though I could hear the hum from my listening position approximately 9’ away.

I’d demand a repair, or refund if possible. No way the amp is meeting that alleged spec, and no $3K amp should exhibit such noise. Simply unacceptable.
My Rowland model 102 (class D) - absolutely perfect silence.
My Benchmark AHB2 - absolutely perfect silence.

Both are silent even when listening in close proximity.  Audible 60Hz is not acceptable IMHO.  Since you tried more than one amp it is likely something wrong with wiring (ground loops?).  I would take it to another location (friend) and try it there.  
It's not acceptable to hear hum thru the speakers from your amp. It's possible that it's the grounding scheme of the Parasound, but before returning it, you need to check the grounding of your Hubbell duplex.
Pull the receptacle from the wall. Is there a metal box or plastic? 
Is the ground wire attached to a ground screw or a metal box? If using a metal box, the receptacle must be connected to it with a ground wire.

A ground fault tester will confirm proper grounding.
https://www.amazon.com/dp/B000RUL2UU/ref=cm_sw_r_u_apa_fabc_2A5ERAZ2Z0Y5P78X4C7T?_encoding=UTF8&...

Have you tried using a receptacle on a different circuit?