Sony WM-33

The WM-33 was a stereo cassette player Walkman manufactured by the Sony Corporation. It was one in a series consisting of WM-32 and WM-43. The WM-32 was a slightly slimmer and lighter model due to lacking the graphic equalizer PCB, however for the most part it had identical transport mechanism and audio IC as the other two in the series.

A red one is very desirable amongst collectors, because it was an iconic design that sold well due to its square proportions and smart impressive graphics on the cassette lid. The three band graphic equaliser gave it a high tech look that was very attractive to buyers at that time. The construction and finish of the plastic was good, and an unscratched new one looks very nice due to the brushed aluminium strip at the front. The Sony logo in a silver-mirrored finish also looks much more impressive compared to the modern designs found today. This is a basic budget-end model that has fast-forward, rewind, and play tape controls, and the push-button mechanism is of course plastic, hence you should use it very carefully.

The WM-33 uses the Sanyo LA4570 IC, which is a successor to the Sanyo LA4520 audio IC. It is a very good chip found on many cassette players, including the Sanyo MGR59. The sound quality of the WM-33 is good providing you ditch the headphones that came with it and use something better.

Graphic Equaliser Design

Since the LA4570 IC has separate preamplifier and power amplifier blocks, they decided to connect a graphic equaliser between them.

Motor Design

A feature of this Walkman that most people did not know about is that it uses an advanced motor design similar to that used on the Sony WM-BF22. It is an unusually large and flat motor that you will not see often and gives a good idea of the direction Sony were taking towards slimmer disc motors that were later developed. Due to this advanced motor design, when you listen to this player, you will notice straight away how smooth the tape speed is. Sony has always been the leader in innovation and it is a big improvement from the cheap d.c. motors that were commonly used by other manufacturers of that time.

From an electronics point of view, this Walkman was a major technological leap forward for Sony and the components they used here marked a new era in design engineering for some of the later models. Once Sony started to improve the motor design, they also began looking into power management functions for the motor. This refinement enabled the later generation of Walkmans to operate for longer periods on just a single battery.

This Article Continues...