Big John’s, located in the Old Town section of Chicago at 1638 North Wells St., was an interesting bar, not a natural venue for blues bands to play their music and attract a lively crowd. But the owner of the bar wanted to draw some new patrons by featuring a musical attraction for the 4th of July weekend in 1963. He was lucky enough to be able to hire two excellent blues musicians, the guitarist Big Joe Williams and the blues-harp player, Charlie Musselwhite. There was barely enough room on the tiny stage at the end of the bar to fit the two of them. But the duo both plugged in their microphones and amplifiers and began to make some serious noise. Soon other musicians joined them, including Michael Bloomfield, who took over guitar duties (and sometimes on piano) after Big Joe left for St. Louis, and soon Big John’s was becoming the place to go to hear good blues music. Other musicians, including a drummer and an electric bass player, rounded out the rhythm section for what was becoming a band, which became known simply as the Group. The engagement at Big John's became a four-nights-a-week deal, and people lined up around the block to hear the Group. These guys abjured any rehearsing, but they played terrific amplified blues impelled by Bloomfield’s guitar and Musselwhite’s gorgeous blues harp. [[[[Dann, 106-109]]]]
But Bloomfield was not a bandleader. He was not comfortable with the lead role in the band, even though he was clearly the most talented among the members. To make matters more complicated, some of the players in the Group were not happy with the compensation at Big John’s, four bucks a night, so they looked around for another place to play, and soon left Big John’s for a bar called Magoo’s – which turned out to be a disaster. But Big John’s, pleased with the success of the loud electric blues-band sound, needed a replacement for the Group, and they hired Paul Butterfield with his guys. The Butterfield band was even louder and tighter than Bloomfield’s Group, and, under Butterfield's strong leadership, they rehearsed early and often. People continued to pack the bar. And it was at Big John’s where Paul Rothchild, producer for Elektra Records, encountered the band once again.
Butterfield had been in a funk, even though the quartet of his band was beginning to come together. They had been playing at a local club called the Blue Flame before connecting with Big John's, but they weren’t getting anywhere. Butterfield had told his friend Nick Gravenites that he was considering taking a part-time job as a commercial artist, and, according to Nick, “maybe he'd give up music and start working for a solid future.” But then Big John’s called, and the career in commercial art was forgotten, as Paul Rothchild encountered Butterfield once again at the club.