Thanks for your replies Chotdavid and Jaybo. And Jaybo, yes I have already tried the Canary on my VA.
I realize that the Canary seems to have a higher amplification. Without changing the volumne control, Canary in fact plays louder than CJ. It gave me wrong initial impression that Canary features fuller body and better dynamic.
In order to compensate the difference in loudness, I have to adjust the volumne whenever I switch the amp (roughly a 3db difference).
The most significant different I can tell now is the midrange. Canary (or the 300B tubes) got more magical midrange to a point that vocal does not sound very realistic... at least I have never heard a real person sings to that degree of sweetness. =)
I will do more listening in the next couple days but quite likely I'm going to hang on to my 11A for a while longer.
cheers,
andy