There is a web site that exhaustively explores the gear Pete, John and Keith used over the years; a visual feast for the tech head and guitar maven in all of us. When I saw John Entwistle in 1996 he had the bass rig his crew jokingly referred to as "Little Manhattan". It was a wall of Trace Elliott gear if I recall correctly.....when he took his solo in the middle of "Shakin' All Over" I thought I was getting CPR!!
I am sure that it is far easier these days to get a great sound on stage that gives you the tone you want without caving in your head