Let me forst say that this is not my amp so I don't have immediate access to it. It belongs to a friend whom I talked into buying it. Anyway... Today he called me to tell me that while he was playing it the sound just started fading to zero. The three 'little' tubes were glowing but the 4 EL84s were not. Sounds like a power transformer to me (I'm not an amp guy at all). This is assuming that the preamp stage runs on a different voltage than the secondary. I could be way off here. Please help out as the closest amp tech is about 100 miles away. If anyone knows of a direct replacent I'd appreciate it or if that's not the problem based on the facts I know please also let me know. All help appreciated guys. thanks.