I've got a Stewart World 1.2 in a 2 space rack with a Demeter H Series preamp. I know, Stewart says keep an empty rack space around the amp. I think that's stupid, but so is when the amp shuts down during the second set because of heat. So, I used to drag this big clipon fan around the country with me. Also stupid, so I had my amp tech do this - see pics. It doesn't take much air at all to keep the amp from shutting down. I whooped it good last weekend and it stayed cool.