Well-kept secret?

[David Roper]

I refer to the apparent early obsolescence of a common tube.

I've noted the use of some odd and/or anachronistic tubes in postwar TV sets, from 1-V to 117N7. But one tube I have never seen used in any postwar set is the seemingly very common 6F6. Every other post-fat-pin output tube imaginable can be found in 40s and 50s sets, including a pseudo-12 volt version of 6F6, namely the 12A6. I thought I'd found a rare exception when a 6F6 turned up in a 16" Motorola set, but it turned out to be nothing more than a doofus mindlessly filling an empty 6H6 socket with what was handy.

RCA tube manuals continued to highlight the 6F6 in their main sections for many years after it ceased being incorporated into new equipment. Is there a postwar set using 6F6 which has escaped my notice?