WM-701C
Technical details, specifications
Functions
Description
It was a combination of all features that made the 701C a milestone in the history of walkmans.
The WM-701C was a Walkman cassette player manufactured in Japan by the Sony Corporation in 1989. It had features such as automatic reverse, Dolby noise reduction B and C, and could accept normal, chrome, and metal tapes. It had an integrated remote control and headphone socket, and operated from a special NC-6WM rechargeable battery, or a standard AA sized battery using the EBP-7 battery adapter. The battery adapter also had a barrel socket to allow powering from other sources such as a mains adapter.
This exquisite cassette Walkman was capable of delivering 5-mW per channel into a 16-Ω headphone coil, and has wonderful sound quality, providing you use a good pair of headphones with it. Sony scientists must have been wondering how many angels they could get to dance on the head of a pin, and of course, the answer is, as many as want to.
It was measuring almost the same size as the cassettes it played. A Sony alkaline AM3 (N) battery together with a fully charged NC-6WM, could get you up to 6.5 hours of operation time.
The design of this unit was a huge step forward where Sony utilised a new tape transport mechanism MT-WM701C-17, which had advanced features such as a better motor, better solenoid, and better chipset. The electronic design was also drastically different, where the signals from the heads went directly into IC301 (MHC8570EQ01L), which was the playback equalising amplifier. It was specifically for magnetic recordings, and is still one of the best preamplifier ICs around. One interesting aspect of the electronic design is that they utilised individual ICs for the functionality whereas later designs incorporated all the processing into one IC. Consequently, it has IC101 and IC102 (NJM2065AM) Dolby noise reduction ICs (one for each channel), TA8145FN headphone driver IC, and LB1672M motor servo. The servo electronics was extremely intricate, having a three-phase motor driven by a DC-DC converter circuitry mounted on flexible board. Finally, there was also the system microcontroller IC µPD7508HG626, which amazingly operated with the rest of the circuitry on a single 1.5-V dry cell!
The WM-701C is often for sale on eBay and due to its popularity, the bidding can go over hundreds of pounds. It was an expensive high-end model back in 1989, so not everyone had one. Since it was a delicately light unit, many would have been broken by now, and therefore there are not very many survivor units out there. They are also difficult to repair due to their compact build because everything is extremely small. Simply removing the back cover can be complicated and therefore the cost of changing just the drive-belt can be expensive.
The WM-701C storage compartment for the NC-6WM rechargeable battery is within the cassette compartment. If you decide to store this Walkman away, be sure to remove the battery otherwise it can make a huge mess if it leaks into the mechanism.
As you can see from the tape transport mechanism, this Walkman has dual pinch rollers and a head that detects all the channels, because of the automatic reverse function.
Via Peter Vis (edited)
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