@david_ten Any recommendations for an upper tier DAC with a very well implemented volume control?
I can second the Metrum Adagio that was already recommended by @bill_k. I owned the Adagio as well as Metrum's Pavane at the same time and after several weeks of side-by-side comparisons, I chose to keep the Pavane and have it upgraded by Metrum to their Level 3, which means the interior build is at the same level as the Adagio, but without the volume control.
The sound of the Adagio is very close to my upgraded Pavane but I already owned a preamp that I like very much and I liked the sound through my preamp just a little bit better than through the Adagio alone. This was probably due to some minor coloration, possibly caused by components in the preamp including AN tantalum resistors in the volume control, Jupiter copper foil caps, Lundahl transformers, or other circuitry. The Adagio had slightly better resolution and both sounded super clean with good staging, tone, bass, and plenty of drive. If I didn't already own that preamp, I would have kept the Adagio and been perfectly happy. There is probably "better" in some way but for a simple solution that gets you off the merry-go-round the Adagio should certainly be on your list.
FWIW, Steve Nugent's well-regarded Empirical Audio DACs also adjust volume by changing the reference voltage. I think there may be at least one more that does that but I cannot remember the name.