1983 WM-10
The WM-10 is a playback-only Walkman.
1983
WM-20
The WM-20 was an ultra-compact playback Walkman released in 1983 around a sliding, expandable mechanism that kept its closed size close to that of a cassette case. The battery compartment, head assembly, pinch roller, and headphone jack all moved together as part of the sliding structure, letting the body stay unusually small without giving up compatibility with full-size cassettes. A clear rounded window exposed the cassette inside, while diagonal transport keys and a manual tape selector supported normal, chrome, and metal tapes.
Sony was pushing miniaturization from simply small enough into something more deliberate and theatrical. The WM-20 was aimed at people who wanted a player that felt genuinely pocketable by home-audio standards, not merely portable. It is one of those models where the mechanism itself became part of the appeal, not just the sound coming out of it.
Miniaturization had already become a Walkman trademark, but the WM-10's telescoping form still felt like a first draft. Six months later the WM-20 delivered the fully realized version, adding Dolby B, metal-tape support, and a sturdier mechanism while keeping the same retracting architecture.
The internal layout used surface-mounted parts and a single cleared edge to make room for the sliding frame, letting the body collapse to the outline of the cassette inside it and extend into a slim, conventional player for use. Weight stayed around 190 grams, and the diagonal control arrangement made one-handed operation easy at a time when portability shaped daily listening.
A single AA cell powered roughly fifteen hours of playback. Frequency response reached 40 to 15,000 hertz, with Dolby B reducing background noise and a selector handling normal, chrome, and metal tape.
Compared with the WM-10, the mechanism felt more certain in motion, and the telescoping action locked into place with the precision expected from Sony's early-eighties engineering. Marketing leaned on the simplicity of the idea.
