Drive System
The drive system is the part of the turntable that rotates the platter in order to spin a record.
There are two types of drive systems in common use today:
Belt Drive Systems
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Belt drive systems consist of a motor and a belt that is connected to the platter
on which the record sits. The motor
spins the platter at a specific RPM. The most common rotation rates for modern turntables are
33 1/3 RPM and 45 RPM. Motors for belt drive systems are usually isolated
or separated from the body of the turntable in order to reduce vibrational
noise. However, the drawback to belt drive systems is that the torque is relatively low,
so the amount of time it takes the platter to get to its proper velocity is much greater than a direct drive system.
Direct Drive Systems
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image/DD.gif
Direct drive systems consist of a motor that is directly connected to the
platter (sometimes the platter is even considered to be part of the motor).
There is an almost instantaneous change in rotational velocity
of the platter because of this direct connection (absence of a belt), with starting and stopping times of around 0.5 seconds.
Another result of this direct connection is that the
torque is much higher than in the belt drive models. Higher torque
means the platter speed is less susceptible to outside forces, which is another
reason why the platter will accelerate to its proper speed faster. This feature is one of the main reasons why
direct drive turntables are so popular with DJs today.