I own the Aurender n200 and in my testing I found there is definite difference in sound quality between the usb and coax output. IMHO the usb output is all around better than the coax ouput. A fairer test would be comparing the nuc and aurender usb outputs to your dac.
750$ Intel NUC vs $6000 Aurender N200: I don't hear the difference
I finally plunged into the source is as important as the DAC belief that is quite prevalent here and decided to test out Aurender N200. And given I have a very highend DAC, thought if the N200 pans out I would go for the N20 or N30.
I was expecting the N200 to blow away my Intel NUC which is 10th gen, core i7, 8GB and running Roon Rock BUT I am switching back and forth between USB playing the Roon Rock, and Co-axial playing Aurender N200, and I don't hear much of a difference maybe a hair, or not even that.
A few caveats: 1) Roon Rock is playing Quboz, N200 is playing Tidal (I am unable to get Qobuz login to the N200 for reason I don't understand).
2) I am comparing Coaxial on N200, USB on Roon Rock.
Caveat #2 can be ignored because I don't hear a difference between Coaxial and USB output of N200.
So either this is an "Emperor has no clothes" moment or I am missing something big. Any thoughts on what I might be missing before I send this N200 back to the dealer on Monday.
Rest of my system: Nagra TUBE DAC -> Accuphase E-650 -> Devore O96 and all Acoustic Revive wiring.