Tube Pre/ Class D Amp - Who has done it?

By way of usual audiophile nonsense, I once had my VAC Master tube preamp ($30K) hooked up to a NAD M22 (nCore class D). It sounded great! Much MUCH better than with matching M12 digital preamp, which was comparatively awful. I even considered sticking with this combo for a while (in my second system), or upgrading to the M23 (Eigentakt). However, in the end - yes, I still prefer either a really good SS class AB (Phison) or tube amp (VAC), versus the class D. But that little NAD M22 was a hell of pleasant surprise, and it’s super for the money (my other amps are much more expensive). However, I think it really benefits from a tube pre to round out its sound for best 2ch enjoyment. Yes, it is "drier" in comparison to really good traditional amps. 

For few years i used Primaluna Prologue Premium preamp with Nord Hypex NC500 class-D poweramp. Was quite happy with the result (Focal Electra speakers). When tested RME ADI 2 DAC with integrated preamp instead of Primaluna, sound was clean, but lifeless, unnatural and boring, in lack of better description. Later switched to Primaluna EVO 400 preamp with much lower output impendence, and that had better extension and clarity, very obvious improvements after few seconds of listening!  

I've done it with a Voyager GAN 300 wpc class D amp with an Aric Audio Motherlode II tube preamp.  Now am running the combo of a PSAudio M1200 class D hybrid monoblocks driven by the Aric Audio Motherlode XL tube preamp.  The latter combination is the heart of my reference system and, for the record, it sounds heavenly.  I have had awesome solid state amps - the JC1 Prarsound monoblock amps for example - but I don't miss the sonics of those backbreaking boat anchors because of the outstanding Audio reproduction of my reference systems.

I’m have a Raven tube preamp from Spatial Audio with a D-Sonic m3a-1200-s amp driving Gunned MMGs.

I use a Italian Lector ZOE preamp, with a CI audio class D amp with excellent results. The ZOE got a major major upgrade when I installed NOS brimar tubes, totally transformed it, the ciaudio is stock except for a excellent Synergistic Research fuse...

Really love having a small light amp that doesn't run hot, and sounds as good or better than my old Sonic Frontiers tube amp that had eight KT 88s, weighed 160lbs, and could heat your house.