The Concert series all use the same power amp. The difference is the preamp. So, for each generation, the Concert Lead has one preamp, the Concert Bass another, and the Concert Keyboard yet another. The Concert Controller II had the same power amp as well.
Same idea with the Coliseum series. The Coliseum power amp was one of the first 2 ohm stable solid state amps, and the Coliseum preamps were, really, four band equalizers instead of the traditional tone controls. Sunn may have been first to do that, too.