Inna, some people can hear better than others in regard to Class A.
In regard to SS versus tubes, some people are music lovers, and some people are equipment lovers.
When I had an audiophile music loving friend, we swore by our "0 distortion" SS gear. I requested a CJ preamp to audition at my home, and invited my friend over for his evaluation.
The CJ was a loaner and produced apparent distortion, but even through this distortion, we both agreed that the music sounded better. Neither one of us has ever considered SS preamps, since.
However, an SS power amp simply reproduces the signal of the preamp; consequently, a high quality SS power amp is acceptable.