Cassette Duplicating Care

Regular Cleaning

Several parts of the cassette recorder and duplicator must be checked and cleaned on a regular basis. Failure to do this will initially result in poor high frequency response. In other words, the sound quality will sound muffled and indistinct. After a while, the level or volume of the recording will decrease. Eventually, you may not get any recording. Another problem caused by a dirty machine is wow and flutter. This is especially noticeable on music. The sustained notes have a vibrato or fast pitch changes which shouldn't be there. It makes the music very irritating to listen to.

So were does this dirt come from? The main culprit is from the cassette tape itself. Tiny particles of tape oxide come off the cassette and stick to different parts of the tape transport. Cheaper tape often sheds more than a premium tape, so it is important to use a good quality tape. The environment also adds its share of dust and lint. A simple cover can help keep that pollution out of your duplicator.

Figure 1

You need to check and clean several areas of the tape recorder and duplicator. The first and primary area is the recording or playback heads (Fig. 1). Any dirt on the heads prevents the tape from making good contact with the actual head. As more and more dirt (oxide) is built up, the tape is moved further away from the metal surface of the head. High frequencies are the first to disappear. Eventually the head can become so clogged that nothing will record or playback.

To clean the heads, gently scrub them with a cotton swab moistened with 99% isopropyl alcohol or a tape head cleaner. DO NOT use rubbing alcohol. It is wise to consult your particular machine's manual for the recommendations. It is also good to check the heads for dirt buildup before any major use. One poor cassette can foul up the heads after just one use, so check them even if you recently cleaned it.

Clean the Pinch Roller and Capstan

Another major area to clean is the pinch roller and the capstan (Fig. 1). These parts maintain the proper speed of the tape. Dirt and oxide buildup will usually be uneven, so the tape will be pulled through the pinch roller and capstan at slightly varying speeds. This is what causes the pitch to flutter. Again, these parts can be cleaned with isopropyl alcohol or head cleaner. However, make sure the head cleaner is safe for rubber parts like the pinch rollers. The other parts which the tape touches, like tape guides, should also be checked and cleaned.

Demagnetize the Heads

The other important aspect of maintenance is demagnetizing the machine. Since tape recording is a magnetic process, the heads and other metal parts can, and will, start to have a small magnetic force themselves. This magnetic force can then change the magnetic pattern on the tape when the tape passes over a magnetized head or metal tape guide. It actually erases the tape a little. That means a master tape will gradually be degraded if the duplicator is not regularly demagnetized. Again, consult your manual for recommended intervals and procedures. There are cassette style demagnetizers which are easy to use. Hand-held units are usually more powerful and can do a better job than the cassette style units.

by Ron Huisinga © 1996 Internet Sound Institute (www.soundinstitute.com). This article is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com

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