Hello all. I am in need of some help if anyone can provide it. My Gallien-Krueger Fusion 550 just isn't producing the power that I would assume that it should be. I bought it a few years ago from a music shop in Tennessee and got it home to Texas. It never produced very much volume...seemed really underpowered. I contacted GK but their rep told me that warranty starts at build date...not purchase date, so I was out of luck as far as warranty coverage was concerned. Not having the money to pay to have it checked out, it just started collecting dust until I could take it to and authorized GK repair shop....the nearest is 150 miles away. Unfortunately that still hasn't happened. At this point, I'm already out the money and still can't afford the shipping and labor costs...so I figured what the heck, I'm just going to try to do things myself. I took the lid off of it and started to check things out. The only thing that I noticed that seemed to be a bit peculiar to me was the middle 12AX7 preamp tube. The dual filaments of the two preamp tubes on either side both burn at a relatively even glow. The middle one has one side that is burning a lot brighter on one side...even compared to the other ones... and barely on the other. Could this be leading to the problem? I've added a photo, and it makes the filaments look a lot more even, but with the naked eye, the middle one almost looks like the one side isn't burning at all and the other one is much brighter. I know this isn't a great way of diagnosing things but I have to start somewhere. Can anybody help?