A Shockingly Straightforward Query

an10490413
  Bob Carver 350s or the Theta Prometheus. The selected amps will be driving a pair of Martin Logan 11A speakers.

"MartinLogan doesn’t publish impedance, phase-angle or frequency response curves for this speaker. However, they do state that their impedance dips significantly at higher frequencies. This low impedance, (0.6 ohms at 20KHz) with a corresponding increase in phase-angle suggests that amplifiers that aren’t stable into low impedances shouldn’t be used.
MartinLogan’s online FAQs recommend an amplifiers that doubles in wattage between eight and four ohms and again increases its wattage at two ohms. This would seem to eliminate most amplifiers from consideration."

 This tells you what sort of amp to look for, and it's not tubes, if you want to extract the very best out of these speakers.
But if your happy with "a bit of a compromise" the the Carver tubes will be fine.

Cheers George  

What I did to decide on the ’best amp for the speakers I want’ was to ask what most other owners of the particular speaker used.
For my (Magnepan 3.6) speaker (back in 2010 when I asked) the answer was overwhelmingly Bryston. So lucky for me my dealer sold both Magnepan and Bryston. 
What I would suggest is doing some Google searches with your speaker name and see what others are using. You may find a consensus. or at least a few most liked brand and models of amplifiers.

an10490413, for what its worth, I use Pass Labs amplification with my Montis (INT-150).  I'm sure many others will work as well.

an10490413 OP18 posts03-05-2019 7:09am

Thanks to all!

George - I’m not happy with "a bit of compromise" at all. Are you thinking something along the lines of Pass Labs monoblocks?

Yes they need amps that are stable, but that can also supply current, so look for amps that can "almost" double (or considerably increase) their wattage from 8ohm to 4ohm and again from 4ohm to 2ohm.

Cheers George