NOS DAC Warmth

I don't know if I'd call either devices generally warm, these are misconceptions IMO as neutral devices are just neutral...it's more a comparison between things that sound harsh versus non fatiguing, and bad recordings will never sound good right, unless gear is just overly smooth and takes away the harsh edges, in which case the gear is non neutral.

That said, I have a Metrum Onyx, paired to a very recently purchased tube integrated, Lyric Ti 140 mk2.  There's no loss of micro detail compared to my SS seperates (Ayre K5xeMP + McIntosh MC 252), it's in fact more resolving,  soundstage however is wider, bass more pronounced...it's a bit more lush, so there's that bit more weight to the music, and it's taste dependent. Intially it felt like a loss of detail but as I hear more and more tracks that I'm familiar with, the details are there and then some...just there's a bit more heft to everything. Good, bad? You decide.

An NOS Dac can present as much detail as any other type of Dac, it’s all based on the implementation and design. IME, NOS may sound more organic and less fatiguing than a Delta Sigma dac.
I actually think a design which implements a FPGA may have the smoothest sonics, but can also present a great amount of detail.

The analogue output stage is what determines the tonal colour or neutrality of the overall sound.

My NOS Dac playing thru an all tube system has a sense of realism and warmth with excellent microdynamics.

@bokat57, "NOS DAC’s have a warmer smoother SQ then over sampling DAC’s"

I have and like both, and my experience has been pretty much the opposite

I don't think these generalities apply at all, but if you want a very warm DAC, check out the ARC DAC 8 or 9.

Besides cost, I can't imagine a good reason to buy a DAC more than 5 years old right now. I _really_ love the DACs that have come out in the last few years at many price points, and I think they all really spank the previous generations, especially with Redbook.