Hi there, I have a problem with my 1994 JCM 800 2205 50w split channel head, which I am hoping someone may be able to offer advice on. I bought the amp brand new in ’94 and it performed outstandingly for the first few years. It developed a fault about 20 years ago, where it sounds as if the volume and tone is being rolled back to near zero gradually and then rolled back up again every few seconds or so. This becomes more apparent and frequent as the night rolls on. I initially thought it had to be valve related, but the amp has had more valves than the toilets at Grand Central Station. I thought maybe transformer, but it has been apparently tested by several service agents. I have spent mega bucks on the head, and where I live in West Australia repair shops are few. It has been to all of them, some many times, and I always get some horseshit story about dry solder joints and the likes. I love the amp and have a couple of other Marshalls which are also very nice, so I don’t want to throw it off a cliff just yet. If you have experienced this or have a theory I would appreciate any ideas.