From Wikipedia the free encyclopedia

The TR-55, released in 1955, was Sony's first transistor radio, and the first to be made in Japan. The use of transistors allowed the device to be much smaller than earlier vacuum tube radios.


Akio Morita and Masaru Ibuka, then operating under the business name Tokyo Tsushin Kogyo, had been working on plans to introduce a transistor radio to the market since 1953. When the TR-55 was released in Japan in August 1955, it was the first transistor radio marketed in that country. The TR-55 featured the Sony name, but the company did not officially change its name to Sony until January 1958.[1]

In the fall of 1955, Morita met with a representative of the Bulova watch company in New York City. Bulova agreed to order 10,000 units on the condition they carry the Bulova name. Morita declined the deal.[2] Sony later signed a deal with New York importer Adolph Gross to distribute an improved and slightly more compact model, and in March 1957, the Sony TR-63 transistor radio would become Sony's first product sold in the US.[2] The TR-63 would not fit in existing shirt front pockets, so the company issued shirts with expanded pockets to salesmen so they could claim the product was "the world's first pocket sized transistor radio".[3]

Technical specifications[edit]

Powered by four AA batteries, the TR-55 used a superheterodyne circuit incorporating two AF stages and covered the medium wave broadcast band. The TR-55 used the following transistors:[4]

  • (1) 2T51 (oscillator-mixer)
  • (2) 2T52 (for IF)
  • (1) 2T53 (AF driver)
  • (1) 2T12

The TR-55's five transistors were designed in house by Sony, the technology having been licensed from Bell Labs. This made Sony the first company to produce commercial transistor radios from the ground up. American company Regency had launched their Regency TR-1 transistor radio earlier in 1954, but bought the transistors from Texas Instruments. Printed circuit boards were used, which was unusual for the time.[3][5]

Physical specifications[edit]

The speaker grille was made from punched aluminum, and its design was reportedly inspired by Lincoln Motor Company automobiles of the era. Although it was not as compact as originally intended, the relatively small size of the TR-55 was a novelty, and attracted the attention of Japanese consumers.[2][5]

  • Height: 5.5 inches
  • Width: 3.5 inches
  • Thickness: 1.5 inches
  • Weight: 560 grams


  1. ^ John Nathan (8 March 2001). Sony. Houghton Mifflin Harcourt. pp. 35–. ISBN 0-618-12694-5.
  2. ^ a b c Robert Grayson (1 September 2012). Sony: The Company and Its Founders. ABDO Publishing Company. pp. 40–. ISBN 978-1-61480-183-2.
  3. ^ a b Michael B. Schiffer (1991). The Portable Radio in American Life. University of Arizona Press. pp. 208–. ISBN 978-0-8165-1284-3.
  4. ^ "Model TR-55, Sony; Tokyo". RadioMuseum. Retrieved 9 April 2017.
  5. ^ a b "TR-55 Product Design". Sony. Retrieved 7 April 2017.

External links[edit]