Hi Arvin and fellow Thieliacks,
Just wanted to offer another option for your 3.5s.. I have found Rogue amps to be a great match with my Thiels. I have a Rogue Atlas Magnum (KT120s, 100wpc) that I use with my 3.7s. I find that it offers excellent (solid-state like) detail and bass control in additions to that luscious tube midrange. With its oversized transformers it has plenty of power and control... loudest I’ll usually go in my 15x20 listening space is about 11’oclock on my preamp dial.
I recently sold my 3.5s (my first Thiel loves) and hooked them up for a few days to say my goodbyes and demo them for the buyer. I was so impressed with how good they sounded with the Rogue that I almost didn’t want to let them go! Compared to the 3.7s they weren’t quite as incredibly resolved and sounded a tad more compressed but they just had this extremely musical and “reach out and touch you” quality that in some ways even surpassed it’s newer siblings!
Enjoy those 3.5s!!