Sony WM-BF64

The WM-AF64/WM-BF64 was a radio cassette player Walkman manufactured in 1988 by the Sony Corporation of Japan. It was similar looking to the WM-AF67 recording walkman, which had an additional record button. There was also the WM-AF64, which was gray in colour and available for the US and Canadian markets, whilst the WM-BF64 was black and for the UK and European markets. This Walkman had the same transport mechanism (MF-WM69-80) as the WM-F59, and WM-F69 models.

Review

This wonderful cassette player with FM/AM radio sounds good with the original open-air type 1E stereo headphones. You get some great functions such as auto reverse, Dolby B noise reduction, and clear audio output of 20 mW per channel. It requires a pair of "AA" size batteries that will provide approximately 8-hours of tape operation, or 20-hours of FM radio. It is a nice little convenient size with dimensions 116.1 mm × 93.1 mm × 37.4 mm, and weight 245-g including batteries, and belt clip.

When I repaired this unit, I thought that the electronic design was superb, as one would expect from anything made in Japan during the 1980s. The radio design uses the TA7787F IC, which contains the FM/AM IF, detection, and oscillator circuitry. It works in conjunction with the TA7370F IC, which is the FM multiplex, and AM amplifier. The chipset was widely used during the late 80s and the Toshiba Corporation of Japan manufactured both ICs. Interestingly, the radio does not use a variable capacitor for tuning, because it would have been too bulky to fit under the cassette compartment lid. Instead, they use a variable resistor and varactor-type tuning circuitry. They also managed to provide three radio presets located within the cassette compartment under the cassette lid. You can see photographs of this and more in the following pages of this multi-page article.

It is worth remembering that the headphone cord also doubles as an FM aerial, and therefore if you are using other non-supplied headphones, it may affect the performance of the FM radio.

Other goodies include a HP901 playback head, which connects to the LA4580M preamplifier that the Sanyo Corporation manufactured. This IC contains the required circuitry for a 2-channel preamplifier as well as a stereo power amplifier for driving headphones. In addition, they also managed to cram in the NJM2063 IC, which provides the Dolby B functionality. This IC is a dual low-voltage noise reduction audio processor.

You will notice that this player has a three-position slide switch for the DBB (Dynamic Bass Boost) function. To achieve this functionality, they had to add yet another stand-alone dedicated IC CXA1249M. Once the Dolby and Bass Boost ICs have processed the audio signal, they send it back to the second half of the LA4580M for power amplification to drive the headphones.

Price/eBay

It is a wonderful player with an iconic look that many will remember owning. It is certainly the one worth having for the collection. I paid seven pounds for mine as it was in good condition and only requiring a new belt, and capacitor upgrade. Obviously, a unit in good working order, and mint condition, together with the original Sony headphones and packaging can sell for much more.

In this multi-page article you can see the inside view of the electronic engineering that went into its construction. Be sure to check out all the pages of this article before you rush off to eBay to buy one.

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