But he's never stopped customizing his gear - a trait he inherited from his dad. Van Halen tells Popular Mechanics: "If it was movable, or turnable, or anything that resembled something that could go up or down, I would mess with it to make the amp run hotter.

"I opened the amp up and saw this thing. I found out later it was a bias control, which controls the power to the output tubes. I'm poking around, and all of a sudden I touch this huge blue thing.

"My God - it was like being punched in the chest by Mike Tyson. My whole body flexed stiff, and it must have thrown me five feet. I'd touched a capacitor. I didn't know they held voltage."