The loctal tube developed by Philco was a boon and a bane to radio and television. The good was the design reduced lead inductance and removed the lossy bakelite base hence before the 7 and 9 pin miniature tubes, performed in higher frequency circuits. The bad is that Philco introduced a full range of tubes more or less duplicating the established octal tube range of tubes. This led to an unnecessary proliferation of tube types for many years.
Perhaps the proliferation helped lead to the boon of the publication of tube substitution guides?
