A $300-$400 turntable tweak

05-18-11: Manitunc
Rockitman,

I dont know if I agree with your statement that the additional weight will not affect a magnetic bearing. Depending on the strength of the magnet, it may not be able to maintain the separation between the bearing surfaces.

That's a given Manitunc. I can easily see the clearance between the magnetic bearing and platter on my table...I agree, too much weight so that the platter makes contact with the bearing would be bad.

Manitunc, Rockitman, magnetic bearings are another thing that I've done experimentation on. In my experience, using the magnets to unload most of the platter weight from the bearing, but leaving some mechanical contact intact sounded the best (a kilo or less, probably even a half-kilo would suffice).

IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing. OTOH, if the finish and lubrication of the bearing points is such that significant noise and vibration are generated as a result of the mechanical contact, you may arrive at different conclusions.

Some of the La Platine Verdier turntables allowed the user to adjust the amount of magnetic levitation, and use the configuration that sounded best to him.

cheers, jonathan

"IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing. OTOH, if the finish and lubrication of the bearing points is such that significant noise and vibration are generated as a result of the mechanical contact, you may arrive at different conclusions."

That is an interesting explanation. May be that is why I tend to prefer mechanical bearing vs Magnetic bearing in my Clearaudio Master Ref analog set up. The Magnetic bearing may not have efficient vib drain path (just a spindle of some ceramic material) to the Everest Stand my CMR rests on

"IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing."

Would not the sleeve/platter interface provide a pathway to drain vibrations, or does the lubricant interface effectively prevent vibration tranfer?

I believe the magnetic bearing in the Project RM10 only unloads the platter from the bearing and doesnt isolate it completely under the same theory that a drain path is desirable. So essentially you have a regular bearing with minimal load and therefore minimal friction and noise with the advantage of a heavy platter for rotational momentum