I have a 1970 Hiwatt which apparently has a rare hot preamp in it, much more gainy than the standard Hiwatt.

Anyway, i made a vid for a guy who was pitching to buy it so i just thought i'd post it for interest. It's single coil at the start and humbuckers from about 7m in.

Stupidly i never maxed the mid at the end so i didn't get the ultimate gain, but if you go to about the 10m mark you'll see it gets pretty heavy.

http://www.youtube.com/watch?v=pF3uDpLQmQU