the funny thing is I don't think Jimi Hendrix used a Plexi on some of those recordings. Many rumor it was a Fender Twin, and more I compare live to studio, I am inclined to agree. Esp with Are you Experienced?
I think Paul Kosoff and Free. Eric Johnson comes to mind, as does Jeff Beck who used Marshall 50 and 100w all over the early JBG albums and Blow by Blow and Wired.