DAC suggestion to pair with MC275 & Usher Spk

I have been greatly enjoying my system, which includes a tubed DAC. I run a late 2009 Mac Mini to a Lenehan Audio PDX Level 2 DAC to an MC 275 MKV out to Totem Acoustic Forest speakers. I have swapped out all of the stock tubes on the MC275 (12ax7s = late 1950s Bugle Boys, 12at7s = early 1960s military spec Mazdas and KT88 = Shuguang Treasure Tubes). I have not yet upgraded the tubes in the DAC (currently Gold Lion 6DJ8s), but understand that dropping in Amperex 7308s will make yet another big difference. The detail is tremendous, with female vocals and acoustic instruments, in particular, really shining. Very, very involving and emotional system. I'd strongly recommend trying out the PDX if you can find a way to do so. Good luck!

It's true that Mike Lenehan has very limited (no?) distribution in the States. He has told me that his preference is to engage directly with audiophiles and rely on word of mouth rather than sink money into marketing. I have very much enjoyed the conversations on the phone and via email that I've had with Mike. He is very, very accessible and completely committed to helping you get the most out of his DAC.

If you happen to be in the Bay Area, I would be more than happy to work out a listening session.

Mike has designed the PDX to be an upgradeable platform, so in that sense, yes, it is a work in progress. I found this to be a plus, but perhaps others won't see it that way.

The PDX can drive an amp directly; that was a key requirement for me. The analog volume control is optional, so buyer's choice on whether or not you'd like to employ it as a pre-amp. I'm using unbalanced Harmonic Technology Pro Silway MKIIs, at the moment. I've tried Mike's RibbonTek interconnects, but could not discern a difference between them and the Pro Silways.

Let me know if you have any other questions!