In the 1930s, as the United States recovered from the Great Depression, most people couldn’t afford a new radio. Even so, the Radio Corporation of America earned a tidy profit on vacuum tubes like the 807, [pdf] introduced in 1937. The 807 proved especially popular with amateur radio operators, as evidenced by this ad from the March 1940 issue of QST, a ham-radio magazine. And in 1947, English engineer D.T.N. Williamson described the circuit for his eponymous high-fidelity audio amplifier [pdf], variations of which used the 807. Although RCA closed its electron tube operation in 1976, 807s are still made in Russia and China, and audiophiles continue to debate the technical and aesthetic qualities of 807s from different companies, eras, and countries.
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This article originally appeared in print as “A Vacuum Tube for the Ages.”
Part of a continuing series looking at the story of technology as told through advertisements.