The Sony Walkman portable cassette player was introduced in Japan in 1979 as the TPS-L2, a stereo follow-up to the monaural Sony Pressman. The blue-and-silver device ran on a pair of AA batteries and unlike portable radios of the day, it dispensed with speakers entirely in favor of headphones. In fact, the original Walkman had two headphone jacks. By the summer of 1980, Walkmans were on the shelves of retailers in the United States, and by...Continue Reading