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

I have been testing our various tube preamps with GaN FET amps and our hybrid  amps (one uses a 12AU7 input stage while the other uses DHT-currently running 2A3’s)

Being a bit biased, my preference is our 2A3 only linestage. The GaN FET modules on their own have a 100K input impedance and the hybrids are min. 100k
The 2A3 preamp utilizes transformer coupled inputs with single ended output  

With the higher input impedance and the better quality of todays Class D amps, it is not to hard to get the sound you want with a tube preamp  just be careful with the synergy with high output preamps with some Class D/solid state low impedance inputs. As always  

I am using the LTA Aero DAC, LTA microZOTL Level 3 preamp, and Apollon Audio PET950 dual mono Purifi amp. Driving DALI Epicon 6's plus a pair of Rythmik F12G-SE subs. The LTA components provide the right level of tubiness, without the transformer-induced distortion at frequency extremes. I am in love with the sound of Ken Rad VT-231 bg 6SN7s in this rig.

My initial impressions were comparing a Pontus II, Primaluna pre + power amp to the Pontus II, Primaluna pre + Apollon power amp.  At first blush, things seemed a little dead and two dimensional, but some fiddling with EQ (minor bump to midrange) solved some of that. Allowing some time to get used to the new sound also helped. The grip and precision on bass is absolutely phenomenal with the Apollon, and the rest of the range is very smooth. I would say top end was also significantly better in definition and air.

I believe the uncompromising neutrality of the Purifi amp exposed weaknesses in the Primaluna. Switching out the DAC and pre for the LTA components was (unsurprisingly) a tremendous step up. Now I'm quite happy with soundstage, tonality, and imaging. It is very musical, and listening sessions always run much longer than budgeted...

I am running Class D Amplifier mono blocks with a VAC Renaissance MkV.

All is well.