This updated model added to the strengths of the WM-D6 by offering an important extra feature: Dolby C noise reduction. This system, which operated in playback and record, improved the dynamic range considerably. Including Dolby C noise reduction in a compact portable was not easy, and the integrated circuits which performed most of the functions had to be made by Sony themselves. The fact that this extra function could be fitted to the WM-D6 without making it any larger was amazing, though it forced some changes, for example the second headphone socket was no longer fitted. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
Other useful modifications were made at the same time. Most useful of these was the addition of a line-in connector, which allowed direct connection to other audio equipment without having to use the microphone socket. This was a great improvement and helped to reduce the background noise level when recordings were made from line sources, such as a CD player, second tape recorder or a mixing desk. The level meter was also altered so that as well as showing the recording level or the battery condition, it could be switched off to save battery power. Text copyright © Walkman Central. Unauthorised reproduction prohibited.
The WM-D6C can easily be identified from the earlier WM-D6 version because the “professional” script on the top cover is green instead of yellow. The WM-D6C could not really be improved upon and so remained in production almost unaltered for many years. However, two significant changes did occur, both in the latter part of the production run. Firstly, the excellent and very effective amorphous head with its distinctive parabolic grind was replaced by a simpler, cheaper permalloy type of a cylindrical section. This later head is noticeably more wear prone and therefore could not be considered an improvement. Only latterly was the “amorphous head” script removed from the badge on the front of the machine so it cannot be used as a reliable guide to which type is fitted. Secondly, the printed circuit was re-drafted to use surface mounted components. These were much smaller than the types used originally, though as the size of the recorder stayed the same the only advantage was a reduction in the cost of assembly. The circuit remained substantially the same as before and offered near identical performance. Text copyright © Walkman Central. Unauthorised reproduction prohibited.