turntable speed control

Let me clarify if I may.  The potential slightly fast speed of a "warmed up" turntable is caused by BOTH the belt and bearing.  As the table is used the belt becomes slightly more pliable.  In some bearing designs this allows the bearing to more precisely align itself and work as it was designed.  The "cold" stiffer belt pulls on the platter harder which can create a chaotic situation in the bearing and reduce its performance.  My turntables avoid this, however I have measured this increase in speed myself, in some designs.  My tables btw, often use the Phoenix controllers and they are excellent and great value.  Drift on my tables, with Phoenix controllers is essentially non existent.

Bruce
Anvil Turntables

anvil_turntables  "...  As the table is used the belt becomes slightly more pliable."

That's interesting! Have you noticed any difference among various belts that you attribute to either the material used to make the belt, or the cross section of the belt?

The Phoenix controller does seem to be unique and a good value.
 

Hi again. My favorite? Surgical silk thread with a light application of instrument string rosin ( applied while table is spinning ). Sounds best and you also feel very cool when your finished. I also like light test fishing line although its a little noisy on the platter and the knot makes a little ticking sound ( which I have not heard through playback). Belt circumference  affects speed so you need a variable controller.
Why not rubber? Rubber belts get micro tears in them ( meaning pliancy is all over the place) and along with wear can really mess up your W&F. The more friction you have in your bearing the more pronounced this is.

Rubber belts have a bigger "fatter" sound, and less pliable belts tend to sound "crisper" and cleaner, generally throughout the frequency range.
Hope this helps.

Bruce

Mr. Creeds, 

not it trying to offend but I own the Phoenix control and tach unit for my VPI Prime. I know for a fact that if you even lightly touch the platter the tach rpm drops instantly. Also - before I powdered my belt - on start up the tension side of the belt was taught but after the belt passed the pulley you could visibly see the band vibrating due to the slack. This was only obvious for a second until the platter speed stabilized, but I would still think this is happening albeit to a much smaller degree once the platter is up to speed.  Wouldn't this be some indication that belt creep is happening to one degree or another?

All i I know is that the system works flawlessly and tach reads 33.33x where x fluctuates up or down .001+/- rpm.  And I definately hear very stable sustained piano notes. So belt creep aside, it does a magnificent job at keeping the platter stable and at a significantly lower price than the SDS. 

Cudos to PE!

last_lemmin"not it trying to offend but I own the Phoenix control and tach unit for my VPI Prime. I know for a fact that if you even lightly touch the platter the tach rpm drops instantly."


No offense taken! I guess what's at issue here regarding speed deviation is what defines a "light touch" and, of course, variations between different turntable platters. I can certainly slow down my VPI platter by touching it - I can make it stop, for that matter.

I've heard nothing but good things about the Phoenix motor control and tach, so I'm not questioning those products at all.