Low-Powered Tube Amp for Zu Soul MkII?


I'm totally new to tube gear, but I just got a new pair of Zu Soul Mark II speakers, and I think my old solid state integrated might need to be replaced with a tube amp. I've been reading that these high-efficiency speakers really like lower-powered tube amps, and I'm wondering if anyone here has experience with them. Here are my constraints:

I have a small room.
I'd love to get something that's made in the 'ol USA.
Preferably around or below $2K.
It would be ideal if it could fit inside our existing cabinet, which is 17.5" deep (this rules out the Cronus and maybe even the Sphinx, unless I make some huger changes).

I love the look of the Rogue Cronus and maybe the Sphinx even more, and these prices are conceivable. But one of my conditions is that I need to be able to hide all this stuff, and my cabinet's too small depth-wise for some of these bigger amps, sadly.

Thanks for any suggestions!
dungan
Schubert, I have never heard a Sophia Baby, but all owners report I've read were always glowing. Certainly there is no need. The particular thread I mentioned explains their experiences. It may be of interest to you.
Just sent it in for some upgrades... and we miss it. It's really sparkly and lovely with the Souls, and it's plenty of power with those speakers and our small space. Having some bass problems, but I think it's our room that's the culprit, as we had similar issues with the previous speakers. Someday we might step up to something some powerful, but I think that might be a long time coming. Really love this little amp.