The Velvet Underground played these shows as part of a 6-week tour of the west coast. The performances featured Doug Yule on bass who had just joined the band after the departure od John Cale. Lu Reed has said that the reason why he had to get rid of Cale in the band was Cale's ideas were just too out there. Cale had some wacky ideas like recording the next album with the amplifiers underwater, while Reed was trying to make the band more accessible."
Charley Musselwhite is an American blues harmonica player and bandleader who came to prominence, along with Mike Bloomfield, Paul Butterfield, and Elvin Bishop, as a pivotal figure in helping to revive the Chicago Blues movement of the 1960s. Musselwhite was reportedly the inspiration for Elwood Blues; the character played by Dan Aykroyd in the 1980 film, The Blues Brothers.
He released the album “Stand Back! Here Comes Charley Musselwhite's Southside Band” in 1966 on Vanguard Records to immediate success. He took advantage of the clout this album gave him to move to San Francisco, where, instead of being one of many competing blues acts, he held court as the king of the blues in the exploding countercultural music scene, an exotic and gritty figure to the flower children.
The Initial Shock were actually from Missoula, Montana and had formed in 1966 as The Chosen Few. Then they moved to San Francisco to join the scene in 1967 and changed their name to The Initial Shock, but sometimes "the" was dropped. They broke up in 1969 due to drugs and personal problems.