Magnetic levitating turntable shelf-opinions?


I have seen two different types of magnetic levitation shelves/platforms for turntables, etc. These would not be hard to make and incorporate into a custom component rack system I'm currently working on.

Does anyone have personal experience with this type of product? Specifically, if you are using it for vibration isolation of a turntable are you satisfied that using such powerful magnets near a cartridge is not interferring with the cartridge performance?

For you scientists out there the magnets used are neodymium and yes, I realize how dangerous they can be to work with.

Thanks for the input,
Patrick
lugnut
I am surely no "magnetic field" expert, but i would think that you would neet to shield the areas directly above ( where the tt is ), below ( where the rest of the gear may be ) and behind ( all of the low level cabling and power cords ). I would think that this could work wonders, especially if you could find a way to mass load the levitating TT. Not only would it be completely isolated from floor-borne vibrations, the mass loading would also minimize air-borne vibrations.

Just do it and let us know how it turns out : ) Sean
>
I built one for my TT after moving it to a location where floor vibrations could not be completely dampened. My major problem was keeping the magnets apart. They can easily be coaxed into flying together unexpectedly and any unfortunate appendages falling between them will suffer the consequences.

I have heard no difference between the table with and the table without the strong magnets nearby (except for the suppression of floor vibration which works admirably). The field is essentially static and strongest at the corners of the platform where the cartridge isn't, so I wouldn't expect there to be much of an effect on the signal. I am using a Grado moving iron cartridge rather than low output moving coil, so your mileage may vary.
Sony made opposed magnet feet in the 70's. "Espirit Line" methinks it was called. Heavy and expensive too. Eliminates all the home made contraption issues. Actually worked. Made that Bulgarian Scrubwomen Choir (the 'reference' show-off LP at the time) really open up and separated the voices. IMHO, fully disclaimered, and showing my age.
=;^)
I'm no scientist, but wouldn't something "floating" on a magnetic suspension be more prone to move with airborne vibration? I thought the theory of vibration isolation was generally to solidly couple the platform to something that wouldn't move (i.e., the foundation). I guess you could make it really, really heavy, but you still have damping problems--if something is magnetically suspended and you displace it, won't it oscillate until friction with the air slows it down?

I guess, if you use electromagnets, you might be able to do something to change the repellent magnetic force dynamically and damp it... There's the idea--some form of active electromagnetic compensator. Then the only problem is finding a reference that is isolated and doesn't change.

; )

Seriously, I'm no engineer, but the theory seems flawed...