“Second song in, the amps blew up. You can hear Jagger apologizing to the crowd, ‘We’re trying to get it together up here. Maybe we’ll do a couple of acoustic ones’”: How a revolutionary amp nearly derailed the Rolling Stones’ 1969 US tour

The Rolling Stones perform at the Boston Garden. Bill Wyman on bass. Mick Jagger of The Rolling Stones.

The Rolling Stones didn't just tour America in 1969 – they rewrote the rules for stadium rock, playing to unprecedented crowds with towering PA systems, a purpose-built stage production and a volume level that pushed contemporary equipment to its limits.

At the same time, their search for a stage-worthy guitar and bass rig had become a logistical headache. The British amps they'd relied on at home weren't always practical overseas, and the band's ever-growing live setup demanded more power than most manufacturers could comfortably supply.