Hello dsper,
I haven’t been able to follow this thread as closely as I wanted, but has anybody suggested the Merrill Audio Veritas class D monos that use the Hypex NCore1200 power modules and 1200 SMPS? Here’s a review that states they don’t quite double power in power for each halving of impedance down to 2 ohms (400w @ 8 ohms, 700w @ 4 ohms, 1,200w @ 2 ohms) but they sound great and are stable down to 1 ohm):
http://www.stereomojo.com/Merrill%20Vertitas%20Monoblock%20Amplifier%20Review/MerrillVertitasMonoblo...
The Veritas sold new for $12,000/pair. With Merrill recently introducing a new line of Element series amps using the new and very fast switching GaN transistors, I’ve noticed numerous used pairs of Veritas monos for sale with an average asking price of about $5,000. I’m assuming many of these owners may be selling in order to purchase a pair of the new Element 116, Element 118 mono block amps or an Element 114 stereo amp.
I believe a pair of the Veritas would be an excellent choice to drive your Thiel CS5s. My thinking is that any seller of a pair of amps they formerly invested $12,000/pair for would have cared for them very well and it shouldn’t be hard to find a pair in excellent condition.
The best new options are probably the new Merrill Audio Element series amps using the new and very fast switching GaN transistors; the stereo Element 114 amp for $15,000 or one of their monoblock amps, the Element 116 amps for $22,000 or Element 118 amps for $36,000. Here's a review of the Eklement 116 monoblocks with comparisons to the prior model Veritas:
www.enjoythemusic.com/superioraudio/equipment/0619/Merrill_Audio_Element_116_Veritas_Review.htmBest wishes,
Tim