Moving Magnet CartridgeA moving magnet cartridge (abbreviated MM) is the most common type of phono cartridge. It has two magnets on the end of the stylus (one for each channel), located inside of the cartridge. As the stylus moves, the magnets change their relationship with the coils in the body of the cartridge, generating a small voltage.
The advantages of a moving magnet cartridge are high output, which means it is compatible with any phono input on a stereo component. Many moving magnet cartridges also feature a removable and replaceable stylus. This is important in the event of breakage.
Its disadvantages are that the magnets have higher weight or mass compared to a moving coil cartridge, which means they can't move as quickly in the record groove. This inhibits its ability to track subtle changes within the groove. This is where a moving coil cartridge has performance advantages.
Moving Coil CartridgeA moving coil cartridge is sort of the opposite of a moving magnet cartridge. Instead of magnets, two small coils are connected to the end of stylus located in the body of the cartridge. The coils are smaller than magnets and weigh much less, giving the stylus more agility when navigating the constantly changing record grooves. In general, a moving coil cartridge traces the grooves better because of its lower mass and provides more detailed and accurate sound quality.
One disadvantage of the moving coil cartridge is that it generates a smaller voltage and requires a secondary preamplifier, sometimes known as a head amp. The head amp increases the voltage enough for a phono input on a stereo component. Some moving coil cartridges have higher output and are compatible with a standard phono input, but its output will be somewhat lower than a moving magnet cartridge.
The stylus is also not user replaceable in a moving coil cartridge and must be replaced at the factory or the entire cartridge discarded if the stylus is broken.
Both types of phono cartridges will provide good performance, but if you want the best, select a moving coil cartridge.