When the amp is cranked, I am not getting nearly as much volume as I should. It's probably 10+ dB quieter than usual. It started happening the other night while I was playing. While the amp is quieter, it's also distorting a lot more. Anytime I strum, the power tubes emit a bright ultraviolet/blue color, which disappears when I stop playing. I've never seen this before because the power tubes are usually glowing orange. It's doing this when I'm plugged into both the Normal and Vibrato channels, so I don't think it's a bad preamp tube. I thought perhaps it was a bad power tube, but I stuck a new pair of power tubes in tonight, and nothing changed. After a couple of minutes, I started smelling something burning, so I shut the amp down and tried to locate where the smell was coming from. I'm almost certain it was coming from the power tubes. Neither of the transformers were hot but the power tubes seemed hotter than I would expect them to be after two minutes outputting low volume. The rectifier tube is still glowing bright orange, so it appears normal but I can't say for sure that it's functioning properly. Before this started happening, the amp was making intermittent popping sounds and also intermittently would drop volume for a couple seconds then return back to normal. Any suggestions?