Walkman DD series

The innovation that made this change possible was the introduction of miniature Dolby ICs that could run directly from the 3V battery supply without the need for a DC-DC converter (as had to be employed in the WM-7, for example).

The next step in the evolution of the Walkman was to add quartz crystal lock to the DD capstan, this appeared in the next model in the series, the WM-DD3.

However, building on the strengths of the previous model, a quartz-locked action was added to the drive motor, providing absolute speed stability under all operating conditions.

Unlike the WM-D6, the WM-DD3 did not offer a facility to defeat the quartz lock and trim the playback speed manually.

Quartz lock aside, the WM-DD3 was nearly identical to the WM-DD2, including the provision of Dolby B NR and switch for normal or metal/chrome tape types.