Prof,
Speaker mating is important especially with many tube amps. I had a VAC Phi 300.1A and it drove my Focal Utopias very well with ample bass control. When I upgraded my speakers to Rockport Altairs, I lost a good deal of bass reproduction. It seemed like the frequencies from approx 100 - 160Hz were lean and as a result overall speaker coherence suffered. I later confirmed this when I switched to a solid state amp with lots of current as the bass coherence with the higher frequencies is terrific.
I don't know much about your Thiel's and the other speakers you're considering, so perhaps they're less demanding and the VAC will drive them very well.
As others have said, Kevin Hayes is an exceptional gentleman and should be able to provide some professional guidance.
Speaker mating is important especially with many tube amps. I had a VAC Phi 300.1A and it drove my Focal Utopias very well with ample bass control. When I upgraded my speakers to Rockport Altairs, I lost a good deal of bass reproduction. It seemed like the frequencies from approx 100 - 160Hz were lean and as a result overall speaker coherence suffered. I later confirmed this when I switched to a solid state amp with lots of current as the bass coherence with the higher frequencies is terrific.
I don't know much about your Thiel's and the other speakers you're considering, so perhaps they're less demanding and the VAC will drive them very well.
As others have said, Kevin Hayes is an exceptional gentleman and should be able to provide some professional guidance.