Before I take my amp to Thermal Relief here in Las Vegas (best amp guys in the city...all the other stores take their amp repairs to these guys!) I was wondering if I could at least diagnose the problem here. My amp started crackling really loud on day when I turned it on. To isolate the problem, I unplugged from my pedal board and plugged right in to the amp. It played OK for a few seconds then started crackling again and the sound decreased by about half. I turned it off and didn't touch it for a week. Today, it wont make any sound. One of the 12AX7 tubes is not glowing but I'm not sure if that's the only problem. Any ideas or suggestions? I'm really just trying to gauge how hard of a hit this is going to be. These amps sound great but maintaining them gets to be expensive. Here is a pic that shows which tube is out.