Founded in Tokyo in 1947, Sansui initially manufactured transformers, but by the 1960s had developed a reputation for making serious audio components. They were sold in foreign markets through that and the next decade. Sansui’s amplifiers and tuners from the 1960s and 1970s remain in demand by audio enthusiasts.

In 1971, Sansui introduced the Quadphonic Synthesizer QS-1, which could make simulated four channel stereo from two channel sources. Sansui developed the QS Regular Matrix system, which made it possible to transmit four channel Quadraphonic sound from a standard LP. The channel separation was only 3 dB, but because of the human way of hearing it sounded relatively good. In 1973, Sansui introduced the more advanced QS Vario Matrix decoder with 20 dB separation.

During the late 1970s, the iconic matte-black-faced AU-series amplifiers were released. The first-generation ’07’ models included the dual-mono power supply AU-517 and AU-717, and the second generation featured the updated AU-719, 819 and 919. The separate pre-amp/power-amp CA-F1/BA-F1 topped the model range along with the AU-X1 integrated amplifier.

In the UK around 1982, the Sansui AU-D101 amplifier and its more powerful sibling the AU-D33, were highly acclaimed by audiophiles and were so well matched to a pair of KEF Coda III speakers that they could be bought as a set from some outlets. These amplifiers used a complex feed-forward servo system which resulted in very low 2nd order harmonic distortion.

1944/12 Founder Khosaku Kikuchi Started SANSUI Electric Production in Yoyogi Kamihara, Shibuya-Ku, Tokyo.
1947/6 Founded SANSUI ELECTRIC CO.,LTD.
1955/11 Founded ONKEN KOGYO CO., for Amplifier Department Expansion in Waizumi-Cho, Suginami-Ku, Tokyo.
1956/1 Renamed ONKEN KOGYO CO., to SANSUI ONKEN CO.
1957/1 Started Production of Pre-Main Amplifier for Exporting
1960/6 Merged SANSUI ONKEN CO. to SANSUI ELECTRIC CO.,LTD.
1961/12 Enlisted the Stock on Second Section of the Tokyo Stock Exchange.
1969/10 Increased the Capital to 1,200,000,000 Yen. Established U.S. Subsidiary.
1970/3 Enlisted Stocks on the First Section of Tokyo and Osaka Stock Exchanges.
1979/1 Developed and Introduced the Diamond Drive Circuit (Patented).
1980/10 Established England and West Germany Subsidiaries.
1984/1 Developed Twin Diamond Balance Drive Circuit (X Balanced Amplifiers)
1987/6 Changed the Company Logo.
2000/4 Moved the Head Quarters from Shi-Yokohama to Kodaira-Shi, Tokyo.