WM-30

The WM-30 was an ultra-compact playback Walkman from 1984 that refined the expandable design of the earlier WM-10 with a brushed-metal body and upright layout that kept its footprint unusually close to that of a cassette itself. Powered by a single AA battery, it combined Dolby B noise reduction with a manual tape selector and a sliding body that expanded only when needed for cassette loading. The whole machine was built around making playback from a full stereo cassette seem improbably small.

Where the WM-10 introduced the expandable format almost as an engineering statement, the WM-30 feels like Sony turning that idea into something broadly usable. It was aimed at people who wanted a Walkman that could disappear into a pocket or bag without feeling flimsy or stripped down. More than a radical departure, it marks the moment when the super-compact branch began to feel like a real part of the range rather than a clever side experiment.