A turntable cartridge is the component that converts the physical movement of a stylus in a vinyl record groove into an electrical audio signal. It is mounted at the end of the tonearm and is one of the most important parts of the record playback process.

The stylus, sometimes referred to as the needle, sits in the record groove as the vinyl rotates. Tiny variations in the groove cause the stylus to move from side to side and vertically. These movements represent the audio information stored on the record.

The stylus is connected to a small cantilever that transfers its movement into the cartridge. Inside the cartridge, this mechanical movement is converted into an electrical signal using magnets and coils.

Moving magnet, or MM, cartridges are one of the most common designs. In a moving magnet cartridge, magnets connected to the cantilever move in relation to fixed coils, generating the electrical signal.

Moving coil, or MC, cartridges operate differently. Small coils move within a magnetic field as the stylus tracks the record. Moving coil cartridges generally produce a lower output signal than moving magnet designs and may require a phono stage specifically designed for their output level and electrical characteristics.

The electrical signal produced by a cartridge is very small compared with the line-level output of components such as CD players and DACs. A phono stage is therefore used to amplify the signal and apply the necessary RIAA equalisation before it is passed to an amplifier.

Cartridges can also use different stylus profiles. Common types include conical, elliptical and more advanced line-contact designs. The shape of the stylus affects how it makes contact with the record groove and can influence tracking ability and the retrieval of recorded information.

Correct cartridge installation and adjustment are important. Tracking force, alignment, azimuth and other settings can influence how accurately the stylus follows the groove and can also affect record and stylus wear.

The cartridge is therefore the part of a turntable that begins the conversion of the physical information stored in a record groove into an electrical audio signal. Together with the stylus and tonearm, it plays a fundamental role in determining how accurately a turntable retrieves music from a vinyl record.