Sushi, I found your post at the AVS Forum where you referenced the following (a-b comparison data)--simply amazing (especially regarding SS amps):

http://www.pcavtech.com/abx/abx_data.htm

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=292828

and a related thread:

http://www.audiocircle.com/circles/viewtopic.php?t=4334&highlight=hear

... when put to the test ... using your ears, you cannot tell the difference between a $500 and a $5,000 solid state amplifier...

the statistics in the study show a 50-50 (50%)correllation--in other words, guesswork when using your ear to try to tell the difference between two solid state amps.

there was a statisticaly valid correllation for tubes--you can tell the difference...

Well, I did not discover that link. I believe that it was originally linked here by (again) JohnK, although I cannot find his original post right now.

Right, Masa; linked it(apparently that link no longer works) and Self's terrific article here .