I have found my Audionote DAC tubes make it through to my speakers untouched. I am using the Fire preamp. It is a class A SS preamp, but you wouldn't know it is even there. My system requires the added boost from the Fire preamp. Running a class D directly with a good tube DAC, preferably NOS, might do the trick on less demanding speakers.
Ice Block Amps
I just purchased and received 2 mono block, Ice Block amps from Seymour Audio. I'm a Cary tube person so this was a stretch for me. Running these through my Cary SLP-05 preamp was just unbelievable. The sound, build quality and price blows me away. I've done lots of SS and tube but this one is unbelievable. I'm not connected to these people in any way.