The crystal and ceramic pickups of yesteryear's record players have been replaced by the magnetic cartridge — now the standard for modern turntables. Although they lack the amplification of the old crystal or ceramic pickups, magnetic turntable cartridges track much lighter across the record, thus causing less wear in the groove. There are two basic types of magnetic turntable cartridges: moving magnet (also known as MM) and moving coil (MC).
A moving magnet turntable cartridge contains a tiny magnet in the stylus, encased between two sets of coils for stereo output. As the stylus tracks the record's groove, the magnet vibrates and generates a small electrical current in the coils. Moving magnet–type turntable cartridges are gentler on records because they require less tracking force, or downward pressure from the needle. Most have a stylus that is easy for a user to replace.
Magnetic coil turntable cartridges also generate electromagnetism, except that the magnet and coils are reversed from that of the MM cartridge. In MC cartridges, the coils are attached to the stylus. Because the coils are very light and made of very fine wire, the MC cartridge type provides superior tracking, better frequency response, and overall sound quality. On the downside, MC cartridges are considerably more expensive than MM cartridges. They also generate less signal and usually require a step-up transformer to eliminate unwanted noise and hum.
Audiophiles debate which type of cartridge is the better choice. Most experts agree that moving coil cartridges deliver better overall performance. Moving coil cartridges cost more and generate less voltage than MM cartridges, however, so they are not as desirable to some consumers. Also, because the stylus in a moving coil turntable cartridge is not easily replaceable, the cartridge typically must be shipped back to the factory or thrown away when the needle wears out or breaks.
Proper installation of turntable cartridges is essential. If the cartridge is not aligned correctly, it will damage both the stylus and the record itself. Other factors that affect cartridge life and performance are the quality of the turntable parts and amplification. For example, if the tonearm on a turntable is not mounted or counterbalanced as it should be, the cartridge's performance will consequently suffer.
There are two types of cartridge mounts: the standard half-inch mount and the P-mount. Standard half-inch cartridge mounts have four prongs in the rear for connecting to the headshell and two screws at the top. The headshell wires connect directly to the cartridge. The P-mount type also has four prongs in the back and is held in place by a single screw on the side.