I just looked up those amazing speakers on HI Engine. Whoa, those look FUN. There is a freshly restored pair for sale in TN for about the 1976 asking price.
Rick Derringer R.I.P
Unfortunately, another major 70’s guitar player checked in for "The Great Gig in the Sky."
Rick Derringer was one of those unique "did everything with everyone " musicians.
https://www.yahoo.com/entertainment/articles/rick-derringer-singer-hang-sloopy-175556224.html