Seeking Advice on NOS DAC

Many thanks to @mitch2 and @acresverde . The Pavane will probably be out of reach (even used).
In addition to multiple positive reviews, Darko really liked the Hex. And there are two currently for sale; I may stretch my budget to $1650 for the right DAC.

Thanks, @jond . I messaged the dealer with some questions. I asked if any service was performed and if the original electronics were intact (very high-quality components are used).
I'm wondering why this unit is so reasonably priced, so I asked for pics.

Can anybody recommend a USB/spdif converter? And wouldn't this signal need to be reclocked and the 5V power be isolated?

FWIW, when I sent my Pavane over to the Netherlands for the upgrade, I purchased an Ayre Acoustics QB-9 DSD because I wanted music and because I always wanted to try one.  It was a nice sounding DAC but IMO and based on my recollection, I would have taken the Hex if I were offered the choice of either.  With respect to full disclosure, I have never warmed up to Ayre's house sound and of the several Ayre pieces I have owned, all have been well-built and very clean and quiet sounding, but I ultimately replaced all of them with pieces I found to be more tonally dense and organic sounding. And the other side of that coin, I have owned 3 Metrum DACs.
Back to the Hex, with the highest respect to Eddie Albert, Eva Gabor and Arnold Ziffel, I find the difference between Hex and Pavane to be much greater than reported by acresverde, but that is my opinion of what I hear in my system.  The upgrade to Level 3 brings another level of clarity and spatial believability.
And finally, if I were in your shoes, I would be looking hard at the Onyx or, if I wanted to ditch my preamp and simplify my system, then the Jade.  Both use the new designed in-house Metrum Transient converter chips that are used in the upgraded Pavane and in the Adagio.
Good luck.

The Comet being discussed is quite far from the NOS sound. The two overarching characters of NOS are timing precision(could be called ease) and treble roll-off, the later being addressed by forward correction in many new production units.

The Comet has a slightly bottom up sound, a richness to it, which makes it pleasing to the ear however the timing performance is lacking due to the use of a minimal phase filter. Its worth saying that this trait may only appear in single-driver systems. I'd call it neither laid-back nor aggressive in sound though it definitely falls to the side of intense colors & slight rounding of the bass.

The only NOS DAC I've had my hands on, and its old outdated tech now, stayed in my system for years despite a raw, mean, lean sound. It's magic trick was proper timing. Instant transients. Microdetail.

The debate is going to come down to what you personally find more relaxing. I've heard a number of modern OS DACs pull off tube tropes: color saturation, fullness, laid-back. Think of NOS more like a widebander in that yes they can tame treble nasties but they're more there for the raw textures and timbre picky. Personally I find timing errors more annoying than any frequency abberations so NOS ends up the sound that calls less attention to the fact it all started as electronic pulses.

Red, everything you've stated is consistent with my research, especially about timing or "ease." Every pro and user review loves the Comet, but NOS seems to have what I'm looking for.
Right now, the Audio Note and Hex are the contenders. But I need advice regarding a high output DAC going direct into my tube amp (1V input sensitivity).

This may be a silly question, but is it helpful to use a reclocker before the input to a R2R DAC? I know the reclocking device should not do any upsampling.