Ah, ha!
I actually managed to hear the change of pitch noise when the screen goes from bright to dim.
I had to crank a powered monitor to a level I would never use for music playback - like really painful loud if I was playing music.
I had my ear right up to the speaker and it sounded pretty much the same type of sound as I recorded through the onboard ADC from the D10.
So, in my case at least there is a noise, and it's repeatable. However, it is well below any meaningful level to disrupt music playback and is inaudible at normal amplification levels.
This also might have something to do with where I have the DAC placed - on top of the PC tower, a cheapy RCA pair coming out, going to a F-F RCA coupling, into 4m of unbalanced cable with RCAs on the end, into RCA>XLR adaptors. 4m of unbalanced cable in a coil on top of the PC tower.
I am kind of asking for noise here.
Saying that, the connection to ADC was with RCA > 3.5mm TRS, no long unbalanced cable. Hmm.
Not amazingly fussed, it sounds great playing music and was cheap and looks great.