Direct-drive turntable
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A direct-drive turntable is one of two main phonograph designs being manufactured today. The other style is the belt-drive turntable. Each name is based upon the type of drive motor used. Both are primarily for playing 12" and 7" vinyl disc records.
In a direct drive turntable the motor is located directly under the center of the platter and is connected to the plater directly. The first commercially available direct-drive turntable, the model SP-10, was introduced by the Technics division of Matsushita in 1969.
The sole disadvantage to direct drive turntables over belt-drive turntables is vibration from the motor. However, in recent years, shock-absorbing (less dense) material, placed between the motor and platter, has been used to cut back on vibrations. Since the motor is directly connected to the platter, the torque is usually much higher than in the belt drive models. Higher torque means the platter speed is less susceptible to outside forces (stylus, hand). Higher torque also means the platter will accelerate to its proper speed faster so less distortion is heard when the record begins to play.
In all turntables a motor spins a metal disk at a constant speed. On top of the rotating disk (platter) is a slipmat and on top of the slip mat records are placed to be played. The slip mat can serve two functions. In the past slipmats were rubber and used to hold the record in place so that it would not rotate independently of the platter. Nowadays the slipmat is used to reduce the friction between the spinning platter and record, and is often made of a felt like material. This way a DJ can scratch the record while the platter continues to spin underneath. In direct drive turntables the slip mat also helps isolate the record from motor vibrations that would be picked up by the stylus. The stylus is a small needle that glides along the grooves of a record and picks up the variations in groove depth and/or lateral movements, these are then converted into audible sound.
Many turntables also include a pitch control, which allows a DJ to mix using a technique know as beatmatching. From the late 1990s onwards manufacturers such as Vestax started to include other electronic controls such as reverse, and "nudge".