@catalysis The reason the AHB2 is a keeper is because it is an outstanding amp. In the top 3 of amps I have heard, I like silence. The fact that it works for me so well with the KEF LS50 is reason alone to keep it since I am not getting rid of the LS50.
My office is small, so some subs are physically not possible. I have heard the CS3.7 sound great with a different amp so I will do some investigation and get it right for me.
I forgot to mention that there maybe a new Purifi Class D amp (hear me out) with much bigger specs than the first iteration could be coming out soon. Now a few folks are raving about the Purifi modules like that review on SoundStageGlobal.com, comparing it with $40K amps. These Purifi amps are in the AHB2 price range and are also almost as silent. They however, have more power where the Thiel CS3.7 could use.
I just read a post by someone from Brazil with a CS3.7 that is expecting a future Purifi amp with 1200 watts at 2 Ohms. He was saying that would be great for his speaker. I think I really need to investigate these new Purifi modules before I go down the road of a Class A or AB amp.
There was some info by TomThiel a few days ago mentioning the AHB2's designers analysis of the various Thiel models and the suitability to the AHB2 or 2 AHB2 in mono. You maybe able to figure out the suitability of the CS3.5 from that post.
BTW - I had the DAC2 HGC into the AHB2 long ago and sold both. When I bought the HPA4 (or LA4) the DAC went up in quality a lot as compared to direct to amp. The Benchmark preamp is incredible, my favourite component from them. I have the DAC3B now but the DAC2 is just as good.