At high volumes my VB3 would make loud, popping and spluttering noises. Hitting the top of the amp would do the same thing. Taking the back off the amp and with the good old chopstick technique, it seems that when I touch the front panel of the amp from the inside I get this awful spluttering sound. My friend mentioned it sounded like a grounding issue but honestly I haven't a clue? I don't suppose there's any Talkbass guys that could give me any advice of what to look for or what to do before I take it in somewhere?