Using digital preamp to tube power amp questions

Al, I have a call in to Mr Goka of Divergent Technologies to get what I can from him re this subject of sensitivity as well as his recommendations for upgrades or cap replacement for these 2 decade old speakers. I'm actually afraid to mess with them too much, though, they sound so good the way they are.
BTW, most of what I listen to has a fairly limited dynamic range and I listen to symphonic music only occasionally so, hopefully, that won't be a significant issue.
Thanks for pointing out the model number; I just knew that it was 2 monoblocks sharing the same chassis and thought they were the SE, not the B's. In reading the online 300SSE manual myself the rating published there is, indeed, 20 WPC. Considering the owner's opinion re the power rating, I'm beginning to wonder what the model really is. He did say it was a custom chassis and I haven't yet seen it.

So did you try it? Or are you just asking hypothetical questions regarding the possibility of such a set up? I strongly recommend you try it. I think you'll be pleasantly surprised. Theoretical audio is never a great substitute for the actual audio, except to rule out dangerous set ups.
What are your current concerns?
I would not use my rarest or irreplaceable tubes. Watch for specific danger messages from the manufacturer and don't doubt their sincerity. Do not attempt while inebriated, or otherwise not in full charge of your faculties! Relax!

Mechans, the Cary amp that I want to try hasn't yet become available so I haven't had a chance to try it. The request for advice, though, wasn't meant to solicit "what if" hypotheses; I seriously wanted to know if I might expect to hear a tube influenced improvement based on introduction of only this power amp. I've had almost no experience with tube based components except for when, going back to the late 50's, monaural and tube amps were the only choice. Also, over 30 years ago I discovered electrostatic speakers and have stayed with them ever since and, based on their inordinate current demands and advice I was given, I decided it best to stay solid state.

Now that I have these really nice monitors I thought it was time to see what I may have been missing all these years. Also, with age, my hearing is changing to the extent that I'm finding more and more music passages that I used to seriously enjoy have started sounding somewhat harsh to the point of discomfort. Now I don't expect tubes to be the panacea for these listening woes but if some of the edges can be rounded a bit and if tubes can contribute to this, the improvement would be welcomed.

Tubes can definitely help with that...

Since you are not changing the speakers, my recommendation is to stay away from SETs, since they simply don't make enough power. You will want 30-50 usable watts; in an SET that means about 150 watts total! Not going to happen (unless you are in a small room, in which case a 20 or 30-watt SET might do).

We make amps that would work with that, and there are many others out there that will do nicely too.