I can tell you first hand having a very expensive Ayon
preamp I borrowed ,the Nad-M51 digital vlume is 35 bit
and to get a -66 db signal before truncation it is impossible to hear in this case this digital direct output is one of the best out there and your amplifier and how good or bad it is ultimately will dictate it's sound character and ultimate resolution. I am running in pure class A with the Parasound Halo amps and it sounds excellent.If I may add the Nad is much better now that I added the Bryston BDP player to an external SS drive
with Wireworld Platinum USB cable ,and XLR.it is now world class at under $6k, and bettered My Ayon Skylla MK-2 dac which was very good and used the same Digital cable ,even did the Hifi tuning for the fuses
when combined with the Bryston bdp and cables the NAD won .
in overall resolution ,Bass and seperation of instruments the Ayon was a bit warmer and softer,and the Ayon has a Triode preamp section built in.By going direct to Amp the Amplifier is the Key.