Googling the term, I see that the 52 tube seems to be an example where
both grids are brought out to individual terminals.
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The #46 is another. The 46 was popular in a number of A****er Kent
radios circa 1932-33. Class B Push-Pull output stages in high-end
radios had a brief run in the early 1930s, then faded into history. --
Ed