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VPI motor - upgrade to 300 rpm?

I hsve a HW-19 mk 4 plus or something, with the Black knight platter and inverted bearing, along with the SDS, The SAMA is the Hurst 600 rpm. This has run, now, for five years. Recently I have had problems with pitch variation, not easy to locate. The problems have been somewhat solved by glueing the pulley to the shaft and by oiling the motor, helping a lot, but perhaps not fully. Should I order a 300 rpm motor and new pulley? Advice is appreaciated, especially, experiences going from the 600 to the 300 rpm motor.
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Showing 3 responses by ptmconsulting

ptmconsulting
1,000 posts
 
Here's a thread discussion thread (sorry, I couldn't resist) but there are others and some that have on-line sources quoted.

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1264987921&openfrom&1&4#1
ptmconsulting
1,000 posts
 
You can easily pick up a new Hurst motor on the web. You don't even have to go through VPI to get it.

On another note, I believe there was some discusison about which motor was actually better. Something to do with the cogging effect, since the number of poles differ on each motor. Maybe someone else who has more knowledge of this will chime in.
ptmconsulting
1,000 posts
 
If you have an SDS then there is one other thing I can highly recommend that you try. Get rid of that vibration prone VPI rubber belt and find some silk thread. Tie a basic knot in the ends and use that instead. You will definitely have to adjust the speed to compensate for the thread's smaller diameter sitting down in the pully groove. You will also definitely need to give the platter a push-start by hand.

The PRAT will increase dramatically, with more detain and better space and air. Not a small improvement and easily one of the best things I did for my VPI.
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