A turntable stylus is the small needle attached to a cartridge and tone arm on audio equipment designed to play vinyl discs, or albums. The stylus is lowered on the arm to rest in the album's spiral groove, and vibrates in the uniform spin of the disc. These vibrations occur from the audio frequencies encoded into the spiral groove of a record. Audible vibration is converted to an electronic signal for amplified playback. Styli differ in shapes and compositions that provide different audio qualities and wear.
In shape, turntable stylus designs include a number of variations for fitting into grooves. The most common are the rounded spherical and conical varieties. Elliptical types offer better quality at higher cost.
The small tips of these styli are designed to respond to slight vibrational cues. These tips can be fashioned from numerous materials, but the most common modern types are made of steel, diamond, or sapphire. Steel types may be cheaper while the latter two are usually the more expensive and better quality.
Conical and spherical styli are the toughest, the lowest fidelity, and hardest pressing; these cheaper types suit playing worn records, as they minimize pops and hiss. Elliptical types present a knife edge to the groove, resulting in good quality for reasonable cost. Numerous elaborations on the elliptical design aim toward extended footprint contact and lifespan, with less wear.
Some varieties use a diamond-shaped stylus for high-quality performance. These come in many brands. A turntable stylus can be fashioned into any number of custom shapes with computer-controlled lasers.
Production processes use a triangular turntable stylus to cut grooves in wax to manufacture recordings. Qualities affecting performance of needles include shape, angle of contact, and the pressure they exert. Special brushes exist for cleaning and regular maintenance of these sensitive devices.
Regular maintenance and replacement of the turntable stylus helps ensure less wear on a record. Material buildup occurs over time, and can damage the groove and adversely affect audio quality. A stylus may be replaced after about 250 hours of use.
Maintenance includes regular replacement of stylus and cartridge. With proper cleaning and care, vinyl records have been shown to experience over 1,200 plays without noticeable degradation in audio quality. Other technologies use lasers for reading frequencies encoded in records.