Hey guys, so I'm new to this forum and just got back from lugging my heavy 5150 (on the bus) back from a local repair guy, who couldn't even fix my problem. Great use of $50.
Anyway the problem breaks down like this:
The master volume on both the clean and gain channels will not drop below 5. If I turn all the post volumes to 0, there is still a loud muddy guitar signal audible (not just noise, but the actual signal still goes through). This problem exists even when using the preamp out only (I've been testing it to see how close I can narrow the problem). If I use the effects I still get a loud muddy guitar signal coming out of the "send" jack (same signal that is present when the POST volumes are all the way down). So there must be some kind of signal crossover.
This leads me to believe (and the repair guy agreed, though I'm not sure how accurate his claims are) that the problem exists somewhere in the preamp stage. I've tried swapping the preamp tubes around but to no avail.
I was wondering if anyone has had similar problems with a 5150 or any tube amp really...any information would be greatly appreciated.