Clipping with Separates with change of Power Conditioner[?]

@carlsbad2  +1.  I get no distortion or haze from high quality wall receptacle.  No conditioner in my future.

I’d just plug the amp right into the wall, as recommended above. 80 Watts of rated power isn’t much. BUT - Class D amplifiers can have very high instantaneous peak power & current demands, and your new conditioner may be limiting this - perhaps the NAD’s protection circuitry (more likely the Hypex module circuitry) doesn’t like these conditions, hence the shutdown.

When running an amp, you want a power condition that is NOT "current limiting". But frankly, I often find it best to simply run amps directly off the wall (if available). I’ve never had a problem doing this, and feel that most of the supposed benefits of expensive power conditioning are way oversold (and I have a Niagara 7000).

Ironically, if your amp were class A it would have a continuous constant power draw, no matter the signal level.

I’m a big believer in isolation transformers.  Really clean up the sound. I use a large 20amp Equi=Tech balanced isolation transformer unit for my preamp, etc.  I would still plug my mono-block  tube amps directly into the wall until I found a couple of 8 amp isolation transformers to plug each in to which has worked very nicely.  Just sound cleaner.  I also have a couple of smaller (5amp) isolation transformers that I plug all the little wall warts, etc into the power the network switch, light, turntable, etc.  This keeps digital crap from getting back into the line. 
Makes for a very quiet system. 

Even better consider a dedicated line from the breaker box to your listening room. Got rid of all hum from dimmers, large appliances, etc. Dropped the noise floor too. Improved clarity, inner details and soundstage.

Tomcarr - Yes you are correct. I have (3) 20amp lines wired directly from the breaker box. Oversized copper conduit with Furutech AC Rhodium plated outlets. Then of course good AC cabling to the isolation transformers. I’ve also replaced the outlet in the transformers with Furutech AC sockets and rewired them internally.

Naturally there's always better and more you can do.  This is the best I can afford for now.  But always adding little tweaks as I come across deals on things I can add.