I just purchased a new Hartke LH500 amp with a VX410 cab. I'm a bit surprised at the amount of buzz this rig generates with the volume past 5. Even with no instrument cable plugged in, its more than annoying. I've found that if I turn the treble knob completely counterclockwise, the buzz diminishes, but certainly this isn't the solution. Any advice on where I need to begin to correct this?