The Synchronous Drive System (SDS) combines a turntable motor speed
controller and a line isolator into one convenient 19" x 3" x 12" (W x H x D)
package. The SDS breaks new ground in clean accurate power delivery using
advanced digital technology and quartz crystal accuracy.
The SDS allows for the adjustment of both the voltage and frequency
fed to the turntable motor. Adjustments are easily made from the front panel
using intuitive, soft-touch controls. The selected output voltage and frequency
are shown using large, easy to read LED displays. The SDS slowly ramps the
voltage and frequency up or down to the selected value in order to prevent
premature motor wear due to abrupt changes. During motor startup, the SDS
increases its output voltage in order to bring the platter up to speed quickly.
Once the desired platter speed has been reached, the SDS ramps the output
voltage down in order to reduce motor vibration and, therefore, the system's
The circuit used in the SDS provides an incredibly accurate line
frequency of great stability. Additionally, the electronic circuitry
effectively isolates the output voltage from the input voltage, doing away with
voltage spikes, low level fluctuations, RFI, and frequency
Instead of merely filtering the power line, the SDS first changes it
into pure DC voltage and then digitally regenerates its own clean signal. This
approach is superior to that used in many of the other power line conditioners
on the market.
The SDS works best with synchronous motor driven tumtables, such as
those from VPI. The speed of a synchronous motor is determined by the frequency
it is fed. It is only logical, then, that a device whose speed is based on the
line frequency will always function better when a stable frequency is
delivered. A constant motor speed translates into a quieter, more faithful
COLLECTORS ALERT: Many historical recordings were not
transferred onto modern records at the proper speed. Using the SDS, you can now
correct the musical pitch of these recordings by varying the speed of your
turntable. In addition, collectors who have VPI tumtables that run at 78 RPM
will be able to accurately adjust them to compensate for the wide variation in
recording speed used in the 78 RPM era.
The SDS is the perfect match for all VPI