TDK SD - 1987 - US
"The rumour is that the SD is a late 70s SA formulation. When they introduced a new SA formulation in the mid 80s, they used the remaining stocks of the old SA tape for the SD range, which then became their "entry level" TDK Type II. Looking at the shell here, and noting its great performance, we'd hazard a guess that this is the earlier generation SA (...). Called SF in Europe but SD in the USA, these are much rarer than the contemporary SA, but in a blind test, you'd be hard pushed to tell the difference. A bit of negative bias and they sound great." Tony Villa
Note 1: 90 Minutes: Lightly scuffed wrapper, but no cuts and no tears. Only 1 available
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About TDK:
TDK was founded in Japan in 1935 as Tokyo Denki Kagaku Kogyo, with its early work centred on ferrite and magnetic materials. That materials expertise became an important foundation for its development into a major name in magnetic recording tape.
Throughout the cassette era, TDK offered a wide range of tapes for home recording, from everyday ferric models to premium high-bias and metal-particle formulations. The AD, SA and MA series became familiar examples of its Type I, Type II and Type IV ranges, earning a lasting following among recording enthusiasts.
TDK’s wider business evolved toward electronic components and advanced technologies, but its cassettes remain a defining part of its consumer-audio heritage. Their distinctive packaging, varied shell designs and broad model range continue to make TDK an important name in cassette collections and recording systems.