However, play that same tape on another, properly‑aligned cassette deck, and the result will be a noticeable lack of brightness and clarity. Because most cassette decks use the same head both to play and record, they'll play back their own tapes pretty well, even if the head is quite severely out of alignment. Like open‑reel machines, cassette decks have to be aligned, a job which is done at the factory, and, in most cases, never gets done again, unless the machine goes in for a head change. Clean the machine thoroughly before every important recording project, and, in any event, at least once a week. The cleaning process is the same as for the heads, the aim being to end up in a position where no more brown oxide is coming off on the cotton bud. In other words, a drop of washing‑up liquid in a cup of tepid water works just as well, and is infinitely cheaper. Proprietary rubber cleaning fluids are available, but most of these are simply detergent in a weak aqueous solution.
Alcohol isn't really suitable for cleaning these rubber parts, as excessive application can cause the surface of the rubber to perish. This also picks up oxide from the tape, and eventually the surface loses its traction, resulting in tape slip and speed instability. So far, I haven't mentioned the rubber pinch roller, also shown in Figure 1. Figure 1 shows a typical cassette deck head and tape guide layout. When no more brown oxide comes off, wipe away any excess alcohol with a dry cotton bud, and wait a couple of minutes for any remaining alcohol to evaporate before putting a tape into the machine. Using a cotton bud soaked in the alcohol, clean the record head, the playback head, the capstan and all the guides, then repeat using a new cotton bud. However, a lesser‑known problem is that of oxide adhering to the tape guides, which can interfere with the smooth passage of the tape, resulting in wow, flutter, and a phasey kind of sound as the tape snakes across the heads in an uneven way. It is generally known that dislodged particles of tape oxide build up on the heads, causing a loss of top end or even dropouts. If your cassette deck has a removable door, this will provide better access for cleaning purposes, but even without one, you should be able to reach the tape heads, capstan shaft and tape guides. Cotton buds with wooden stalks are recommended, but the plastic type seem to work fine too. A litre of the latter will cost you about the same as a tiny bottle of the former, and though you may have to wait a day or two while the pharmacist orders it for you, a litre will last for years. For this, you'll need a pack of ordinary cotton buds (the things that people poke - wrongly - into babies' ears), and either an exorbitantly expensive bottle of head‑cleaning fluid (which is really isopropyl alcohol with a small amount of dye added) or a bottle of isopropyl alcohol from the chemists. My advice is to forget all about head‑cleaning tapes, and use the traditional cotton buds and alcohol method. Furthermore, there's still a hard core of reactionaries out there who refuse to clean anything at all! Clean MachineĪt the risk of sounding like someone's mother‑in‑law, I'll start off on the subject of cleaning the cassette deck, because, even though most of you get around to doing it, some ways of cleaning are more effective than others.
There are several factors that can cause a cassette machine to perform below par, most of which, fortunately, we can do something about. Nevertheless, when on top form, analogue cassettes can sound very good indeed. Perhaps we're expecting a lot of the humble cassette in an era when we take CD and DAT for granted. A significant number of SOS readers' telephone enquiries or Crosstalk letters relate to difficulties in either producing a cassette recording of acceptable quality, or the age‑old problem of a recording sounding OK on the machine on which it's made, but quite different when played back on someone else's machine. The compact cassette format is now over two decades old, and though there have been improvements in hardware design, noise reduction technology, and tape formulations, the cassette is still considered by many to be the carbuncle on the backside of modern‑day audio. Love it or loathe it, the analogue cassette looks set to be the primary medium for the distribution of recorded music for the foreseeable future, and we have to make the best of it.
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