I bought a SWR LA-15 off of musicians friend at a great deal of 230 bucks, and dont get me wrong, I love it to death, but there is still the reason for getting it so cheap. Whenever I turn it on it makes this loud, high pitched squeal, though when I turn the volume all the way down it doesnt make this sound. I've had it for about 6 months and it really isnt a big deal really, but I figured I would ask incase there is an easy way to fix it. Any suggestions would be nice. Thanks TBers.