Your tube preamp and ss amp thread

Yes major differences but probably more due to overall design of specific amps used than the general operating Class. 
I would say sound of the Class D Bel Canto amps I use currently resembles sound I have heard in the past with Krell and Classe amps.  Makes dynamic speakers sound more like electrostats (think quad and ML). Very fast effortless and clean but also with dynamics intact.  

I like the tube preamp and SS power amp combo. You should try it both ways because tubes always fail and power amp tubes are more costly. If you have to re-bias the tubes each time, that is also a pain. A lot of people are into class D power amps, I haven't tried one myself.

I have run a Audio Research tube preamp with a Pass X350 for over ten years. An excellent combination. I had stayed away from tube amps because of the reliability ‘ biasing need. Then a couple years ago the Audio Research rep came through with the new ARC REF 160m (mono blocks). Micro processor controlled tubes... no biasing and greatly increased tube life... finally I thought. As soon as the REF 160s comes out I’m getting one. I did. As soon as I swapped it in I realized I should have put up with a tube amp earlier. The richness of the midrange and bass simply isn’t in the same ballpark.

The Pass XA series will be more like tubes. If you are headed that way. I think it would be a really difficult transition. But I would go with Pass, he is an outstanding amplifier designer.

I have a Supratech 6SN7/DHT pre amp mated to the AGD Audion mono blocks. A true upper class combination, i use the 45 tube option.

Modwright LS100 tube pre with Modwright KWA100SE ss amp