"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.
"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?  

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.

Have you tried using a receptacle on a different circuit?

Obviously no one is reading the post. The OP changed out three amps, all had hum, albeit to a different degree. So the problem isn’t the Parasound or any other amp, it is a problem with your power and the Parasound is more affected by it. Do you have any fluorescent lights, dimmers, led lights or other noise producing things on that circuit? Particularly dimmers... they are notorious. You could have a ground loop, you could have a faulty interconnect. Not an easy problem to nail down, start with any dimmers etc. they are the easy ones.
  If not too difficult do what I did. There was a teeny bit of drywall cutting involved but depending on your house layout may be easy peasy.

   Get dedicated 20a line from your box.

   Well worth the 500 it costs me . For sure. I had a small amount of static but could  not be heard from the seating position. After . None nada. Also it is better at higher listening levels when pushing things. Way more relaxed sound with better bass. I am knocked out by this 500 mod. My volume on dac to amp is about 6db higher on an everyday basis with 0 fatigue.  

@yogiboy I was more excited about integrating the new amp into my system and with settings. I never noticed a hum in my system ever before. I can't say if there was hum before I changed the receptacle. I do plan to switch the receptacle back to stock to see however....

@helo thank you I was thinking the same thing and was really surprised tech support told me that actually. 

@lowrider57 the receptacle did have a ground which I attached. I do need to pull it off the wall again to make sure it didn't come loose pushing it through the gang box 

@mofojo thanks for that. I think mine is dedicated but I'm not 100% sure now..

@geof3 I do have dimmers around in my listening area. I suppose even if the light isn't technically on the dimmer is still working? I didn't think about this one. Might try and disconnect or cap off one of the receptacles 

I'll report back to the post when I have an update 

Hum is not acceptable! That Parasound 5-channel amp has an internal ground problem someplace between the circuit boards and the chassis. The design team should have fixed this problem before production! Nothing you can do externally will fix it!
The hum is there even if I try connecting the amp power cable to another receptacle so it's not the new receptacle it seems. 

@jasonbourne how do you know that it's internal? Is it because there is still hum even with all wires unplugged except for the power and speaker cables?

Can you also hear hum emanating from inside the case of the Parasound, or is it only from through the speakers?
@twoleftears the speakers only. Can't seem to hear it from the amp itself. The midrange driver seems most affected. The tweeter gives off a faint hiss but not noticeable unless I'm right next to it ear to tweeter. 
OK Try this.....this worked for me..I have no reason why. I tried dehummers and I have a power conditioner. Still slight hum was there.

Take the faceplate off and remove completely the screws holding the outlet to the box. Then pull the outlet out slightly to where the metal frame of the outlet is not touching the box. Now see what happens. When I did this, all my humming went away. So I placed a small rubber washer between the box, where screws go, and the outlet and purchased plastic screws to hold the outlet in place instead of the metal ones. Worked like a charm
It is 2021, any audible amplifier noise floor and hum is unacceptable to me!

I put my ear on the twitter and hear no audible noise or hum.

Your Parasound amp has a ground loop problem IMO.
@jwl244,                                                                                                                                OK. When you changed your receptacle to the new Hubbell did you cheek the Hubbell for phase. If you reverse the hot and the neutral on the receptacle by mistake, it could cause a hum. BTW: The faint hiss from the tweeter, is the amplifier gain just lower the gain knob on the back of the amp. Hope that help. Mike
@ditusa thank you for that. I will have to check on what you said. The faint hiss I don't mind so much but thanks for that knowledge as well!
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.

Reviving an old post:

I have an A52+ Parasound amplifier, and I love it’s sound, but it has started making a hum in channel 1 that is very noticeable from the listening position (accross the room.) Replacing the amp with another amp and the system is dead quiet. The A52+ makes the noise with no inputs connected, just a speaker connected. This noise is still present using a different power outlet.

The Parasound technical support says this: "It sounds like the normal noise floor of the amp. Channel 1 and 2 will have slightly higher noise than 3-5 because of the proximity to the power supply. If your speakers are higher sensitivity than average (above 90db) it will be more noticeable."

I think that is totally unacceptable. Going to take it back and try and get it fixed. It’s still under warrantee. I hope to get a better resolution than "that’s the way it is".

Do you have a cable tv setup box etc?

Check it , disconnect it, they do not ground correctly on installation.

I run 10 tubes in my Cronus Mag ll and alternative

 Croft I have zero him of any kind at 90db speakers at the speakers.