I have two topics to address, and I could really use some help: 1) I have a Peavey Classic 20 that I've been using as a practice amp for the past 3-4 years. It's a great little amp and hasn't really required much maintenance except for the occasional tube change. But recently, after a tube swap, I've noticed a problem. The amp starts up fine, and sounds fine. But after about 3-5 minutes of being on, the amp gives off an electrical burning odor. I can pinpoint what this is, as my technical experience with amps is limited. My guess is that it may be the transformer, but I'm not sure. 2) My main rig is a Dr. Z Prescription ES head and Z Best cab. The amp sound incredible and is very loud, but I use an airbrake to tame it most of the time. I normally use pedals for my OD tones, but this amp is designed to have some great natural tube OD, hence the "Overdose" option on the amp. I've just recently been starting to try and get that natural overdrive from the amp, using the Airbrake to manage the volume levels. Here's the problem. When I crank the amp up around 7-8, with the overdose engaged, and the Airbrake at full attenuation, I get some of the most horrible sounds out of the amp. It sounds like the tubes are being spit out and the speaker cones are being stomped on. It gets worse the more aggressively I play, too. The amp is loaded with new tubes, with the EL84s being about 2 1/2 months old, and the preamp tubes being anywhere from 6-8 weeks old. I've been playing mostly in my apt. with the volume low, and put in maybe about 5-6 hours a week on it. What could the problem be?