Interesting problem.....the other variable is source media. Most of your media sounds ok, but you mention some are poor? Is it always the same media that sounds bad?
Class A amps are can be excellent or poor. They do not escape the designer/manufacturer and the quality of the materials. This is no different than any other piece of equipment. When done correctly, they are very detailed and warm.....and I do mean WARM! For serious listening, it would be excellent. For home theater, it would not. An amp of that design would certainly expose any other weaknesses in your system (source, cabling,etc)
This could be a very long discussion, and I won't discuss what a Class A amp is unless requested.
Regards,
BBIBH
