06-19-15: Bdp24
I just checked my Music Reference RM-200 amp, and it has 8ohm, 4ohm, 2ohm, and 1ohm taps! It's a very stable circuit, and a good sounding amp. And the only tube amp I can think of that would work with the load of the Thiels. Give Roger a call and see what he thinks. He's an expert with difficult speakers, having designed the electronics for the Beveridge Electrostatics, and having a current direct-drive ESL/tube amp product.
These would be nice as a tube alternative but you would have to use the 2ohm if not the 1ohm tap. But you'll only get around 20watts per channel off these taps, then only problem is at 87db the Thiel's won't go too loud before the RM200 clips. Ok if you don't listen too loud.
Cheers George