I don't know if this adds anything to the thread but I thought I would quote from a book I'm reading at the moment. It is from an interview with Chuck Rainey where he is being asked if he ever got to know James Jamerson: "I knew who he was as far back as 1959, because the Motown acts used to tour all around the Great Lakes area. We first met at a huge concert in Ohio in the early '60s; I was playing with Big Jay McNeely and he was with the Miracles. Someone in the previous band had borrowed my amp and blown the speakers - so I plugged in and just pretended to play. Afterwards, James came up and told me I should have plugged into his amp, which was right next to mine. I appreciated that, and since then I've done the same for other bassists."