Back in the late 70's we were doing a three piece Van Halen type band, vocals only, very loud, and all we had was a Kustom mixer, maybe 100-200 (a very loud and clean 100-200 watts) with a pair of Cerwin Vega 1-15/horn speakers. It was never not loud enough. I think the old gear was more conservatively rated. We did not run any monitors, and had all our guitars and bass through the amps. Drummer was very loud, he played Slingerland marching drums converted to a drum set and used rock knockers, solid sticks, to play. Saw him shear toms off the mount/drumset. Loudest player I have ever seen. We never even thought of putting a mic on the drums.