It totally depends on your own tastes and criteria.
Some people will say you need the most powerful sonic state amp you can afford to get the best out of Thiels.
Others will say Thiels sing with tube amps (which typically are lower powered).
I’m in the Thiels-on-Tubes camp. For me certain tube amps maintain everything I like about the Thiel sound - clarity, image density, truth of timbre, sense of aliveness, incredible imaging and soundstaging, while reducing any tendency towards aggressiveness or brightness and adding an even more believable organic quality to the presentation.
Do I trade off the last iota of dynamic capabilities of my 3.7s? Probably, but that has typically been the trade off of tubes over powerful solid state amplification, and yet many still choose tube amps because they find the gain more than they lose, and find they loose more than they gain when they hear the speakers with as amps.
Thats why no one can really tell you which amp would work for you, at least until you can get more specific about the characteristics that are important to you.
For me my Thiel 3.7s and my 140w side Conrad Johnson Premier 12 tube amps have been a match made in heaven. My pal who reviews for SoundStage is totally blown away when he hears the system.
