“I’ve had years of listening to that Goldtop and now, I own it”: Sum 41's Deryck Whibley and Dave Baksh talk perfect guitars, going from amp stacks to profilers – and the difficult decision to say goodbye

How Sum 41’s valedictory album, Heaven :x: Hell, came together on the simple arithmetic of pop-punk and Slayer-inspired thrash, for an album that's light, dark and all shades between