I just got myslef a Peavey Rage 158 ampifier, the retailer said that the amp had onboard dist.. i tried it there wasn't any distortion.. that was after i bought it. THe manual said that there was a medium distortion but 2 me, it wasn't like it. The are knobs and button to adjust the settings... maybe that's the solution to getting heavy distortion.. plz help me out.