Output valves in push-pull amps were usually EL84 (15w) or EL34/KT66 (50w). The Vox AC30 used four EL84s in dual push-pull, self-biasing configuration, and the AC100 used a similar setup with four EL34s.

ECC83/12AX7 were usually used as pre-amp valves, and had a tendency to go 'microphonic' - if you tapped them, you'd hear it through the loudspeaker. Quite handy for acoustic feedback...