750$ Intel NUC vs $6000 Aurender N200: I don't hear the difference

I get it.  I just think you found your answer over a year and a half ago when you posted this:

“The lesson I have gotten is that the effect of the server mainly depends on how competent your DAC is with input signal. Mine (Nagra Tube DAC) seems to be very competent because of various design reasons and has taken particular efforts to negate the bad effects of USB input. So I don't need to waste time with music servers just like Jay with his MSB Select 2 DAC. YMMV.”

Your conclusion there is consistent with actual data from reports done by Paul Miller of Hifi News whenever they review streamers.  He shows the amount of jitter and noise as inferred at the receiving DAC, and the quality of jitter rejection and noise filtering is highly variable across DACs.  But in certain cases, no matter how great the measurements are for a streamer, it’s largely irrelevant because of the DAC.  I think you just need to declare victory and enjoy the music.  Another less costly approach would be to try one of the much less costly streamers out there that measure magnificently - e.g. Volumio Rivo - and see what you get.  Here’s the review/measurements of an Aurender, btw:

and here it is for a Volunio

and here’s the Aurender you actually tried, right?  The much more expensive Aurender’s measurements are marginally better played thru the Mytec - a cheap DAC compared to yours! - but likely inaudible.  And the N200 thru the Mytec measures exactly the same as the Vokumio. Just sayin….

oops, hers the link:

@mdalton I read that review and saw the section you linked us to. What that means, at least to me, is:

1. the USB and reclocking capabilities of the signal of the Mytek and dCS DACs are what’s expected from DACs at this level

2. does not in any way indicate how any of the streamers plugged into those DACs sound like,

3. Does not indicate that dCS and Mytek sound alike either

Measurements is only a part of a complicated chain that impacts music reproduction. Measurements and specs don’t indicate how a component Would sound. If you take a tube DAC like the Nagra or the Lampizator or ARC, there’s a very good possibility that a Topping D90 will measure better in some areas. It don’t mean that it will sound better. That’s been my experience. YMMV.