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Old 5th Nov 2012, 5:43 am   #28
GP49000
Hexode
 
Join Date: Mar 2012
Location: Sonoma County, California, USA.
Posts: 405
Default Re: Garrard record player deck identification.

SL55, SL65: Autoslim meets the Synchro-Lab motor.

The next step in the evolution of the Autoslim chassis was the introduction of the Synchro-Lab motor. Prior Garrards had used induction motors which could vary in speed under different conditions, while good engineering could minimize these effects. Such factors as line voltage and varying amounts of bearing friction caused by "running cold" or "running hot" could alter the running speed. Typically Garrard assumed a variance of 2% under "normal" operating conditions as being normal.

In 1968 the induction/synchronous motor, named "Synchro-Lab" by Garrard, was introduced. Its speed was determined by the frequency of the alternating current supply. Conventional hysteresis-synchronous were higher in vibration, particularly if made large enough to rapidly accelerate a record player platter from rest to playing speed. The induction/synchronous design got the platter up to speed quickly, like the induction motors heretofore used. A second section of the motor's armature took over as the motor approached top speed, and locked to the frequency of the line current. This new type of motor was just as low in vibration as the induction motor. These characteristics made it ideal for use in record playing equipment and it was a patented Garrard innovation, exclusive for two years before being licensed to other manufacturers who wished to use it.

Garrard did not limit the new motor only to its highest priced machines but also installed it in two low/midpriced Autoslim chassis models, the SL55 and SL65. Respectively these were the 50 Mk II and 60 Mk II, unchanged except for the new motor and nameplates. The SL65 was the ultimate Autoslim-chassis model, with a fully counterweight-adjusted, dynamically balanced tonearm; weighted, nonmagnetic, machined platter; cueing device; the capability to intermix different size records automatically; and the Synchro-Lab motor.

SL55
SL65
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Last edited by GP49000; 5th Nov 2012 at 5:53 am.
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