Hi Warren, we communicated about your new 3.7s on the Steve Hoffman forum.
I've been "Thiels with tubes" for decades, myself. I use Conrad Johnson Premier 12 140W/side monoblocks and they have driven every Thiel speaker I've had great (Thiel 06, 02, 3.7, 2.7). And actually one of my favorite pairings with the 3.7s was my little 14W Eico HF-81 tube amp!Certainly not the last word in bass tightness (though surprisingly good), but wow what a sparkling, lush, organic yet lively presentation!