When tube amps are rated at... say 100 watts... that's 100 watts before the tubes start clipping. So, that's 100 watts clean. JerryP at FJA mods had a Peavey Triple XXX (rated at 120 watts) that got up to 190 watts, but that was well into the clipping stage.
Tube power clipping = good :D
Solid State power clipping = bad :mad: