It sounds like you are set on a tube amp, but are you open to solid state? The reason I ask is I was previously using a Cary V12i that offered 50 watts triode and 100 watts ultralinear, which appears to be enough to drive your speakers (if you decide on Cary I might recommend Cary modified AES Six packs as an alternative). I was using the Cary with a Joule Electra LA-100 MkIII and the combination was very synergistic. I recently switched to a TRL D-225 and combined with the Joule Electra I am getting the sound you are after. This is a very transparent fatigue free set-up with excellent imaging, soundstage, and micro/macro dynamics. The bass is to die for and I never realized the amount of roll off on the low end with the Cary amp until I plugged in the D-225. Cost is $4k new with a no-risk trial period.
From a tube perspective, before settling on the D-225, I was looking at both high powered push/pull and SET designs, as well as the flea powered SET amps. Unfortunately my speakers are not as efficient as yours, and like you my preamp and speakers were not going anywhere. The tube amps I was researching which I would recommend are VTL, Berning, and 3-D Audio (custom made SET amps at a very reasonable cost).
Best of luck with your search.
From a tube perspective, before settling on the D-225, I was looking at both high powered push/pull and SET designs, as well as the flea powered SET amps. Unfortunately my speakers are not as efficient as yours, and like you my preamp and speakers were not going anywhere. The tube amps I was researching which I would recommend are VTL, Berning, and 3-D Audio (custom made SET amps at a very reasonable cost).
Best of luck with your search.