Enjoyed reading all your comments to explain this technical area. Very difficult to understand things without a diagram and that’s what’s needed here.
I think the term ultra linear is marketing in nature and I dare say most people have no clue what they’re buying when they do. I remember loudness controls on a receiver I had a while back and was curious at times and clearly pushed more power through the circuits. It’s all about compromise which can be understood without getting terribly technical and my decision was to do biamping of a solid state and tube amplifier. At least the harmonics are more favorably affected and I do really like isolation of tubes in the upper area and let solid state handle the heavy duty stuff below. It seems to be working pretty well so far.
But again it would be kind of nice to see a diagram of all this to better understand the differences between modes of operation which on this amplifier tend to be switchable so easily which always raises skepticism in my tiny mind. But ultra linear does drift more toward solid state and isn’t that what we’re really saying overall after all