I have a Laney GH50L going into a Mesa Boogie 4x12. When I start to play its fine, but recently, after 10 minutes or so the volume begins to waver between normal and drastically lower. Before I get it checked out, any steps I can go through to find the problem? I got both used, the Laney in March, but its in perfect condition, and the tubes are apparently from only past November
It's most likely the power tubes. Any time an amp acts funny but doesn't fail to work completely, that's where you start.
gahh sounds expensive...I'm completely broke
check craigslist for tubes, you might find some real nice (NOS) ones for cheap.