| The cartridge Cartridge types Apart from a few oddities that have appeared over the years (there have been ribbon and photoelectric models, for example), all cartridges with hi-fi pretensions operate in a way Faraday would recognise, by causing lines of magnetic flux to cut coils of wire, inducing a voltage. The only major point of divergence is which element is caused to move in sympathy with the stylus: the magnet or the coils (diagram 6). |
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| Moving magnet (MM) cartridges, which are often and rather unhelpfully called simply 'magnetics', come in a variety of forms, most of which do not, in fact, move a magnet at all. Instead the magnet is fixed in the body close to the stylus assembly; what moves on the end of the cantilever is a high permeability material (e.g. permalloy) in which the magnetic field concentrates. When this moves it displaces the field with it, inducing a voltage in the coils as if it were the magnet itself that was moving. | ||
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