Before the transistor, a portable radio was a heavy box of hot, fragile vacuum tubes that needed two separate batteries, one just to heat the filaments. That changed after December 1947, when William Shockley, Walter Brattain, and John Bardeen demonstrated the first working transistor at Bell Laboratories. The first commercial transistor radio, the Regency TR-1, arrived in November 1954 from an unlikely partnership between Texas Instruments and an Indianapolis maker of TV antenna boosters. It cost 49.95 dollars and sounded thin and tinny.

This episode follows the pocket radio from costly novelty to cultural force. American firms proved the idea but could not make it cheap. Masaru Ibuka and Akio Morita could, paying 25,000 dollars for a license to the Bell Labs patent, building their components in house, and renaming their company Sony. Their TR-63 of 1957 arrived just as the baby boom, teenage spending money, and rock and roll converged, and it took music out of the family living room for good.

• Texas Instruments had a manufacturing yield of only 20 percent at launch, so four of every five transistors were thrown away, and the TR-1 used just four of them.
• The TR-63 was slightly too big for a shirt pocket, so Sony allegedly gave its salesmen custom shirts with oversized pockets. It also popularized the 9-volt battery.
• Prices fell to about 15 dollars by 1962, and by 1964 no transistor radio was built entirely from U.S. components.
• At night, AM signals from stations in the American South bounced off the ionosphere to Jamaica, where musicians reworked New Orleans rhythm and blues into ska and later reggae.
• As circuits shrank, radios turned into novelties shaped like a Jimmy Carter peanut, Charlie the Tuna, and the egg ship from Mork and Mindy.