Belt traction.
The movement between the
motor shaft and the plate is carried out by means of a rubber strap that hugs
on one side a pulley located on the motor shaft and on the other a drum placed
under the plate and concentric with it. The displacement is achieved by means
of a movable pin. This system is widely used as it provides good filtering of
motor vibrations. The rubber band is usually synthetic rubber and its active
face is rectified to obtain a high uniformity of movement.
Direct drive.
In these record players, the motor shaft coincides with that of the platter, which is why the motor must rotate at the same speed of rotation required by the disc and must have two speeds (33.3 and 45 rpm).
It
is in principle the simplest system, although it requires quite complex
and highly elaborate motors, since there is no filter element or damper
of the vibrations of the motor that if they were would be transmitted
directly to the platter and then to the cartridge and to the loudspeakers.
This
system appeared in the market in the year of 1970 obtaining great
popularity that in turn caused that the cost of its production lowered.
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