I’m interested in the Cornwall IV’s and have been researching them. My present system has both a class A amp (Pass XA25) and Quicksilver Mono 60 tube amps (which can run KT77s, about 25w each).
After doing a bunch of research on these very sensitive speakers, I see a lot of evidence that lower watt amps are the most musical match with these speakers. We’re talking less than 30 wpc. So, First Watt, Decware, 300b amps, that kind of thing. Such amps should be able to play all kinds of music, easily, and likely provide the best pairing with the Cornwalls. Again, this is based on my research.
If I go ahead and get the Cornwalls, I’ll be trying them with amps from 3 watts to 15 watts or so.
Just my two cents.
You might also look here or here or here, or on the Klipsch fora, here.