[Arran]

I have a number of used ones kicking around that I extracted out of junk chassis, and out of various radios where someone decided to add a phono jack  to equipment that was never intended to have them, such as any radio built prior to 1938. RCA jacks are still in production, but I don't know whether the old style ones with a phenolic insulator are, there are some really inexpensive ones available but the mounting is different, they are the kind that are secured by drilling a 3/8'' hold in the chassis, and are fitted with a large nut and washer like a potentiometer.
Regards
Arran