Moving-Coil Head Amplifiers
Moving-coil cartridges are generally accepted to have a better tracking performance than moving-magnet cartridges because the moving element is a set of lightweight coils rather than a magnet, which is inevitably made of a relatively dense alloy. Because the coils must be light, they consist of relatively few turns and the output voltage is very low, typically in the range 100–550 μVrms at a velocity of 5 cm/s, compared with 5 mVrms from the average moving-magnet cartridge. Fortunately this low output comes from a very low impedance, which, by various technical means, allows an acceptable signal-to-noise performance to be obtained.
Moving-Coil Cartridge Characteristics
There is much greater variation in impedance ...