Tube amplifier to power Sonus Faber speakers?

or you may try also KR Audio amplifiers....sort of half way between the tube and power of SS.

"Since the minimum recommended amplifier requirements for your speakers, according to Sonus Faber, is 50 wpc, I think you can forget about 300B tubes or something of that ilk. Unless you can swing a pair of VAC Renaissance 70/70 monoblocks. That's 65 wpc of push-pull 300B's, total of (8) 300B tubes could be costly."

I have a VAC 30/30 myself. It can easily drive the OP's speakers. I had mine on a pair of Martin Logan SL-3's for a few years and never lacked for power.

I would like to suggest ARC as a tube amp to consider. FWIW, I believe ARC is currently using SF as its reference speakers when checking the performance of its gear.

That should be no surprise since SF and ARC are member companies of the Fine Sounds Group. This may be a leap of faith on my part, but that might permit an inference that ARC and SF make for a good match.

The specific ARC amp you might want to consider is the Ref 75. This pup has garnered quite a bit of favorable comments. I own its big brother, the Ref 150. The two amps share similar circuitry and probably share a similar house sound.

Not sure how much you want to spend, but the ARC Ref 75 is a keeper.

I use the Audio Research VSi60 (50wpc) tube amp with my Olympica II speakers and find it to be an excellent match. I typically listen with the volume between 30-40% of full on and it can play quite loudly if I turn it up higher. The Olympica III is more sensitive than the II so unless you'll be using them in a very large space or typically listen with the volume really high, the VSi60 might be a great option to consider depending on your budget.

. .... Sonus Faber Olympica 3 speakers. They are 90DB and a 4 ohm load. I've always preferred tube amplification and am finding it a challenge to identify ..... rather 300B or something of that ilk. I tried an 845 based amp but found it edgy and limited in power and....

Ready for Challenge .... great .... That is the right spirit to invest endless time to try to match a mismatch... 300B with 90 dB amps... What a great idea. ... Ever saw a Duck with teeth? No? Don't worry, you will find that one sooner ...
Good luck -:)