Thiel cs2.3

^^^^what Matt said.  I’ve used 501’s with Thiels for years.

When a manufacturer claims that their amp is “stable” into a given impedance; all they are saying is that the amp won’t go into oscillation into that impedance, it doesn’t suggest how much power, distortion, or quality will be delivered into that impedance. Don’t assume the amp is truly capable of performing appropriately into a given impedance, unless they spec it as such. If the amp can deliver the goods; the manufacturer will brag about it.

I think Macintosh tends to be a little bit on the soft side tooAren’t they

^They have that reputation. The models with autoformers are somewhat unique, could be an issue with the CS 2.3’s rising impedance at the bass frequencies.

I have been told before that the 2.3’s were always well regarded speakers