Technics turntables use a direct drive mechanism to drive the wheel of the platter in order to make it spin.
Technics has been able to perfect this method over many years and as a result the Technics SL 1200 MK3 is the most widely used among DJs around the world.
The direct drive mechanism is attached directly beneath the platter by way of a motor that spins the platter above. In order for the platter to pick up speed quickly, almost instantly, it needs torque.
The direct drive mechanism is a system of gears and magnetism designed specifically to provide enough torque to the platter in order to play a record instantly and at a constant speed without drag.
As a result, instant torque is provided to the platter, long playback life and greater control for the DJ.
In contrast, a belt drive turntable use a different system.
The belt drive system uses a 2 part mechanism. It uses a motor and a pulley. The motor is off to the side and pulley is connected to the platter.
A rubber belt is attached to the motor and the pulley. When the motor is activated the rubber belt turns the pulley and the platter spins above it.
This belt drive system uses less torque because the motor is not directly connected to the platter and poor playback performance can occur over time due to the loosening of the rubber belt.
As a result the platter needs to build up enough torque to provide a constant speed for the record to play properly and it offers less control to the DJ.
Turntables also use what is called pitch control. The basic pitch control uses a slider that manipulates the speed of the platter at a “+/-” 8%-16% or even higher depending on the turntable.
When the slider is moved to the “+” side the motor gives slightly more power to the gears or pulley and thus the platter spins a little faster. When the slider is moved to the “-” side the motor gives slightly more power to the gears or pulley and thus the platter spins a little slower.
This is used to give the DJ greater control over the speed of a record when mixing one song into the other without loosing the beat.
Traditionally the motor on the direct drive turntable transferred motor noise to the platter and then to the stylus but shock absorbing materials have provided a cushion and have eliminated just about any noise coming from the motor.
Because the motor on the belt drive system is off to the side noise from the motor is drastically reduced.