buget used amp ?

Yup that was the deal with me. I went with higher wattage amps on the Mac and they would just open up.. A C20 is the bomb for a great sounding Adcoms.. They all needed tone control, BUT good tone control. C20s have a Bass contour, loudness and tone control. The tube roll is icing on the cake.

Until then

Class ds are gonna be boomy and gloomy with that pre. Better off with an A/B of some sort..

What about Crown for the power and bang for the buck. You can always move it to a bass position and even go with a little valve amp for the mids and highs later on.. Keep the cost down but a plan for the future without breaking the bank..

Respect..

what about a B&K Components - ST-140

I used that adcom pre with a B&K Audio ST-140 with fantastic results.

your budget if you can find one.

https://www.ebay.com/itm/B-K-BK-ST-140-power-amplifier/264764252558?hash=item3da52de18e:g:Ez4AAOSw8R...

I think it’s a bit of a shame to drive your excellent speakers with a $500 amp, but to each his own.  There’s a Bel Canto S300 available here for $750 that at least won’t offend your Thiels.  Best of luck. 

I would go with a B&K stereo 202plus, an adcom gfa 555 series 2, or a parasound hca 3500 for your thiels because the thiel speakers need some power to get a full sound out of them and all these amps will do that some more than others but all are quite capable performers.