The 6A6 is a 6N7 on a UX7 base (actually the small seven pin or USS7) and dates to the early 1930s. The Tung-Sol data-sheet refers to the 6A6 as being on the medium seven pin base which is the UX7.
It was designed for use as a zero bias Class B push-pull audio output stage. The design was a development of the American Type 53 and the later and more popular versions were the 6N7, 6N7G and 6N7GT.
The triode sections seen end on. The getter holder is on the lower right of the image.
The triode sections side by side with the extended anodes facing the outside.
The classic envelope is 44 mm in diameter, and excluding the UX7 base pins is 95 mm tall.
References: Data-sheet & 1043. Type 6A6 was first introduced in 1933. See also1933 adverts.
