The Brook was a push pull 2a3 if I remember. THe one I use is a SE 2a3 amp. I don't believe overall amps add too much of a sonic signature, as long as they are well executed. But they are fun hardware to play with! and sometimes good tube amps add pleasant distortions! I have a lot of tube amps and love them. They do somehow make the music sound more involving than solid state. probably by blunting out harshness.
-akhilesh