I am glad Warren told you that.
There is a major misconception out about the claim that using RCA to XLR cables would result in 6 dB lower gain but that is totally false. An amp's gain is the same as it doesn't even know what's at the end of the preamp's output.
It is true that if you have a preamp that has both unbalance/RCA and balanced/XLR output, then if you use the RCA output you will get 6 dB lower voltage than if you use XLR output. So if you use an AVR that does not have XLR outputs, you may not have enough voltage to drive the Hypex amps to their rated output voltage.
That is why I have been emphasizing the first important step when considering which power amp to use is to figure out your actual power need, if you want to make sure your preamp has enough voltage. In your case, the RX-A1080 will not be able to take full advantage of the NC502MP (based on the ASR measurements), but I think this has been covered earlier and you must know that already, that if and when you do need much more power than you do now, then it will have to upgrade the AVR, or use those Cleanbox thingy, that to me, would defeat the purpose of acquiring a power amp such as the NC502MP that offers exceptionally low THD+N.