Lately I have been having a problem with my amp/cab, I was hoping you guys could help. When I turn it on (MAG300) my cab (SWR 1x15) distorts like crazy, making a loud low freq noise with no tone. I have checked to make sure the cables are all in correctly and they always seem to be. Usually after I turn the amp on and off a few times, and pull out/in all the cables the problem goes away and everything works fine after that. This happens even if I turn the Output all the way down- Output seems to have nothing to do with the volume of the Noise sound. I have been extremely careful with both these pieces of equipment since I got them. Has anyone experienced anything like this before?