"It's one louder," insists frontman Nigel Tufnel in This Is Spinal Tap, as he shows off a guitar amplifier whose knobs go up to 11. "It's not 10," he says. "Most blokes we be playing at 10." Amplifier manufacturer Soldano bought into that theory when creating its 100-watt Super Lead Overdrive amp and made it so it could go one louder. The company's Lucky 13 Head, however, beats that: Its dials don't stop until they reach 13.