The BM-550 microcassette recorder is typical of the miniature dictating machines in the Sony range of the late 70’s. These models were very small, even at this stage in their development, and although not intended for music or entertainment purposes, the potential was clearly there. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Although the BM-550 was mono, it was fitted with a two-channel head, the second track being used to record “cue” signals which could be heard when the recording was replayed on a suitable desktop machine. While the Microcassette was never more than a business format in Europe, in Japan there were attempts made to launch it as a hi-fi medium. Unlike the similar sized Philips mini-cassette, the Japanese microcassette used capstan drive, so the speed could be made stable enough for music. Full-size mains operated stereo recorders for inclusion in a hi-fi system were offered by Sony and others and cassettes were made that used metal tape. Some stereo headphone portables were made, though they were never very popular in the UK. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
The BM-550 itself was beautifully made and finished, looking as much like a miniature spy-camera as a tape recorder. It included a built-in microphone and loudspeaker, two speeds and a tape counter. Two “AAA” sized cells were used to power it, again keeping the size to a minimum. An external microphone could be used, along with an earphone for personal listening. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
It would have been technically feasible to base the Walkman idea around the microcassette. The players would have been much smaller and in time, the quality could have been on par with that offered by the normal audio cassette. However, following this route would have confined the Walkman to the Japanese market, where it would have probably been quickly forgotten. By instead opting for a format which was universal across the world, success was assured. Text copyright © Walkman Central. Unauthorised reproduction prohibited.