buget used amp ?

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.

I've been using a NAD 2100 with my Adcom GP555 ii preamp to power my Theil CS1 speakers for over 30 years with no problems.  I think you can find one for around $200. The more power the better though.