i was jamming with my band one night and i had my amp turned up all the way for about 30 minutes non-stop. i noticed that my sound completely cut out with no warning or "pop". the lights were still coming on but there was no sound coming from the amp whatsoever, it turned out to be a blown fuse (T630a 250v). while attempting to replace the fuse, i accidentally shattered a tube (el34). so i got a brand new JJ e34l and a new fuse. once i had everything back together, i started playing through the amp and the crunch channel sounded unbelievably bad. it sounded very weak and the harder i strum, the more it would break up. the best way to describe the sound is if you turn your gain all the way up, put a distortion pedal cranked in front of it, and then turn your volume on your guitar down to about 3/4. after being disappointed, i decided to try the clean channel and it sounded very good like it did before it broke down. im so confused!!! please help
The problem only on the dirty channel suggests a preamp tube issue. Also, you should replace all four power tubes with a matched quad, running one mismatched power tube is not a good idea.