The needle is the most important part of the cartridge, which directly reads the vibrations of the sound frequency from the plate. All modern cartridges and even the best phono cartridge use technical diamond needles mounted on a thin console. The cost and quality of the needle depend primarily on the processing of diamonds.
Needles are divided into two types: with point contact and linear contact. In the first case, the contact spot between the diamond and the groove on the plate is a point, in the second – a line.
The needle has two key parameters: the first is the transverse diameter, the second is the contact area. The smaller the transverse diameter, the better the needle reads the high-frequency components of the soundtrack, the cleaner sound. Moreover, the larger the contact area, the less pressure on the groove, the less wear on the plate and the needle.
- Spherical needles have the largest transverse radius and the smallest contact area. They usually produce a flat but dull sound that lacks detail in the mid and high frequencies.
- Elliptical needles provide much higher reading accuracy due to the small transverse radius.
- Hyperelliptical needles are an improved version of elliptical needles with a larger contact area and a smaller transverse radius.
- Higher-class needles usually have a shape that follows the shape of the cutters used to make master discs. They provide even higher reading accuracy and even lower wear on the plates.
Materials of manufacture
Modern needles can be corundum or diamond, and sometimes combining both materials. The diamond part has excellent hardness but is not suitable for acetate plates. A diamond needle with a corundum tip, which combines ductility and hardness, is considered universal.