The situation: I have an Egnater TOL50. It's my baby. Two weekends ago I did a show at a video game store, no stage, PA only for vocals, and ended up having to turn the amp all the way up to get the volume out of it I needed (the place was so full, the crowd was bumping into me as I played). I've never turned it up that loud before. The next day I had practice with my other band and after two songs I blew the mains fuse. I replaced the mains fuse and checked out the power tubes. One of them was not glowing blue like normal and had burn marks on the insides of the glass. I replaced it with a spare EL34 I had laying around. I don't own a multimeter to bias the amp, nor do I much like poking around in amps since electrocuting myself inside one a couple years ago. The problem: One band is starting to record a demo today and will be recording the next four days. I have at least 8 or 9 shows in the next two months including a SXSW gig and cannot leave the amp at the shop for two weeks to get it biased and checked out. I have a backup (a 50w JCM800) but it doesn't sound anywhere near as good. The question: Will it be okay until I can get a break in my schedule to take it into my tech? Obviously the tubes are no longer a matched set, and I don't want to cause more damage. EDIT: Sorry for the long sob story!