I've got a 50w JCM900 myself, and i have to say, when cranked a little (>3), it sounded great, and in a practise session, i had it at about 5 or 6, and it was plenty loud. Gain was great at those volumes too, didn't need the Rat at all. Just a shame that the one i've got is only a single channel, switchable master volume model, so i can't have a clean and a dirty channel.