"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
For updates
1. The receptacle neutral and hot wires were not reversed. I checked.
2. I switched the new Hubbell recep out for my old one (common 20 amp one). Hum was still there. 
3. I bought a new and better power conditioner. Hum did not change.
4. I lifted the ground with a 3 to 2 prong adapter. Hum still there. 
5. Parasound service mentioned channel 2 is closest to the toroidal transformer and thus may have the most affect on hum. This is true and I would up rearranging the hum out of my fronts but it still present in my rears now where i switched them. Still audible from my listening position. 

Today I had a really weird thing happen. I was further trouble shooting and messing around. At some point the hum was almost "jumping" around. First I heard it in my Outlaw amp (runs my ceiling atmos channels). It sounded like it was coming from inside the amp itself. When I turned it off the hum jumped into my subwoofer. I don't know what I did but I just turned it all off and put it all back together. It went back to just hum in the 5 channels like it always was.... very confusing to me but suggests the issue is my system rather than parasound? @geof had mentioned this. I still have not tried removing the light dimmer from the line. 

Parasound does not really have any more to add and did state they would check it for me. I have to ship it to them (which I pay) and they would ship it back free. 

The dealer who sold it to me suggests I have to plug it into someone else's home's receptacle to see if anything changes. At 50+ lbs i'm not excited about this idea but i'd consider it......
Once again, you’ve got another problem somewhere in the chain, bad cable, funky power etc. Time to go deep and look at your electrical system, most importantly that particular circuit. An easier way to troubleshoot the Parasound is to take it and put it into a different circuit, use an extension cord, or move it to another room on a different circuit with a pair of speakers of some sort.

Someone mentioned a sub, that could be a part of the trouble too. At this point it is unlikely the Parasound.
Same hum with subs disconnected. 

Tried hum x which didn't help which I figured since the ground lift didn't either. 
I know this post is a few months old, but wanted to say that I recently acquired a Halo A51 and have the same issue as the original poster. Prior to this I had a Rotel RMB-1075 which was silent.
The hum I have is audible from the unit itself once powered on and the sound is transmitted to all five speakers even when the receiver is completely disconnected from the amplifier. I have called Parasound for their advice, but seems like they may not have much else to offer.