Sony WM-EX510

The WM-EX510 and WM-EX512 were stereo cassette player Walkmans manufactured in approximately 1995/1996 by the Sony Corporation. They were virtually identical except that the EX512 had remote control capability, whilst the EX510 did not. This multi-page article including the photographs is for the EX-510 model.

• Three settings of Mega Bass (Max, Mid, Norm)
• Dolby Noise Reduction
• Blank Skip
• Automatic Volume Limiter System (AVLS)
• 5 mW per channel into 16 Ω
• Dimensions: 108.5 mm × 78 mm × 28.5 mm
• Mass: 215 g

Review

It’s a lovely early model without a remote control; however it has tiny switches for selecting the required functions. Interestingly the blank skip and AVLS switches are hidden inside the battery compartment. The tape transport mechanism is very advanced and has a three-phase disc motor similar to the later designs. The transport mechanism design is very similar to that of the WM-EX1.

The electronic engineering is based around four principle integrated circuits, and in this early design there is a plethora of discrete transistor circuits as well. I was especially impressed with the three-transistor DC-DC converter circuitry they managed to miniaturize and pack into the unit.

The main audio IC that provides the pre and power amplification functionality is the BA3612KV by the ROHM Corporation. Back then, many engineers in the industry considered it to be one of the most sophisticated audio integrated circuits to have been produced.

The system logic control is provided by the MSM6576 microcontroller IC operating at 32.768 kHz, whilst the motor drive and servo functionality is provided by the MM1279XVBE IC. Interestingly, in this design they decide to use a separate Dolby B type IC NJM2185V by the New Japan Radio Corporation.

The sound quality is excellent of course but it all depends upon the type and quality of your headphones that you use with it. I simply used a pair of Sony vintage headphones capable of reproducing Mega Bass and it sounded wonderful.

Price/eBay

These units sometimes come up for sale on the auction site and the price can vary greatly depending upon condition. I managed to get the unit alone, and luckily it came with a user manual, which was very useful. My unit was in good condition, and apart from some dust, it had hardly been used and simply required a replacement drive belt. A unit in mint condition together with its original box and accessories would be highly sought after by collectors and audio enthusiasts. The nice thing about this design is that the drive belt is easily replaceable by an experienced engineer and one does not have to desolder the top PCB. The photographs in the following pages of this multi-page article show the inside engineering and may be of interest to a collector.

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