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How to improve belt quality

Belt is critical component of every cassette player. That’s why choosing correct belt for your cassette device is very important.

Belts can be used on various places of your cassette decks, for example main belt, inter-capstan belt, mode belt, counter belt… Some are square, some are flat. The most discussed belts are those that affect audio quality. Old good belt producers are gone forever and current belt producers cannot make belts of quality required by sensitive cassette deck mechanics.

These are three parameters that have to be taken into consideration, when choosing right belt:

  • belt quality
  • belt dimensions – circumference, width and thickness
  • belt material

Using incorrect belt will have negative effect to tape stability, wow/flutter, mechanics noise and parts wear. Each cassette transport is designed to use belt of specific parameters. It is always good to find balance between belt length, belt thickness and belt material. Some mechanics require elastic , some require harder belts. Some are more sensitive to correct belt, some less. It is given by design.

There is wide choice of generic belts of various lengths and types on today’s market. There are suppliers of generic belts, like ASWO here in Europe, or turntableneedles in US. They are very cheap, optically they look very good. The only problem is that their surface quality is not sufficient enough to meet specs given by manufacturers of cassette decks. Some transports, like Aiwa dual capstan transport, are very sensitive to belt quality.

Fortunately, quality of flat belts can be significantly improved using method of sanding, presented in the following video. It is possible to use this DIY method using very cheap tools, at home environment. The only tools that you need is 600 grit sanding bands rotary tool. As a result, surface of such  belt will be smooth, uniform and flat.

By using this method, I could reduce wow/flutter from 0.07% (10 sec peaks) WRMS to 0.03%, by just adjusting belt A of Aiwa XK-009 cassette deck. This method was tested in various cassette decks with similar results.

Belt improvement procedure