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VPI SDS speed question

I have a VPI TNT mk.III set-up w/ flywheel. I am using 2 belts, bypassing the hubs as suggested by others. Regardless of how far away I place the flywheel from the motor, I need to reduce the voltage on the SDS to about 55.7 hz. Should I be concerned that the motor is way off? I assume the motor should run pretty close to the 60hz when aligned via strobe disc. Anyone else had this experience?

Thanks,

Jeff
jmslaw
4 responses Add your response
yagbol2
66 posts
 
By the way, put the strobe disk on platter using a strong FLOURESCENT lamp. It is imperative that flourescent not bulb or those new energy savers. Better if you have a K.A.B. with a dedicated light source or Clearaudio makes one, too.
jmslaw OP
95 posts
 
Thanks for your responses. I did configure the 2 belts correctly, and I still can't get above 55.85 hz. With the tri-pulley arrangement, my SDS was set about 58.7 or so.
yagbol2
66 posts
 
The reading on the SDS should be in the 60hz vicinity. Make sure you remove the tri-pulley so the big belt must go directly to the flywheel. If you don't take the tri-pulley out you will overstretch and strain the belt and your reading will be in the 55hz area.
franks
151 posts
 
This is perfectly fine. I noticed the same thing when I changed to the mk5 bearing and platter and stopped using the tripod system/pully. Definatly set the SDS voltage via the strobe disk and enjoy.
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