Classe Amps 100,200,300,400 vs 101,201,301,401

Is there any difference between the older and new amps besides cosmetics? And also I heard that the CA-300 and some of the other amps had a problem with ground hum, did they ever come up with a way to eliminate it?
All Great Amps, But with the 301 and 401 they use some of their Omega technology. I own a 301 and Im amazed at how quiet it is.
Yes, there is. From the 00 series to the 01 (and progressively, year after year it seems) the always musical Classe amplifiers sound more open, transparent and detailed with ever increasing bass resolution while still sounding remarkably life-like.
Anyway you slice it, fine amplifiers...........

peter jasz