I have a few of these RCA/BURLE tubes, 7213 and 8792’s. Planning to use them in an amplifier project. Trouble is that sockets are hard to come by, but my friend Raco Hirkic VA3YP sorted that problem out by making a custom tube socket.
(Edit: 26.07.2012 Added a few pictures)
I have several of these RCA tubes as well. Have you gone ahead and built an amplifier using these tubes? Thanks for any info!