[chadh]

I can't believe I'm about to post something in The Lab!

It's snowing heavily right now, so nobody can move around town. I'm at home playing with the kids, including a session with some of their little magnetic construction toys.  Those magnets are strong suckers: little 2 inch long rods that will cling to either side of your finger.  So I start thinking that it must be pretty easy to build an effective magnetic suspension platform using relatively inexpensive magnets.

Has anybody tried this?

I'm imagining a wood platform sitting inside a wood box with magnets sunk into the both the platform and the box, along the bottom and the sides of the platform (maybe they'd need to be epoxied in place).  Some of the magnets would be set to repel each other (giving the suspension), but some set to attract each other, so that the platform doesn't just pop out of place.

Would this make sense?

If you did the outer box in clear acrylic, you could even impress your friends with the floating platform.

Chad

[cab]

There are commercial products that do this. I have made one as well from rare earth magnets. You must have some sort of guide or rail system to keep the two halves in line with each other; otherwise, the platforms will twist relative to each other and quickly stop levitating. I used two small posts on the bottom platform that went into two bearings on the top. Magnets around the perimeters. Works well....

[chadh]

Hmmm, it seems that we run up against a little problem called Earnshaw's Law, which establishes two things:

1.  The inherent and unavoidable instability of the equilibrium achieved with static magnetic fields; and
2.  That I probably should never post in The Lab.

Chad

[chadh]

There are commercial products that do this. I have made one as well from rare earth magnets. You must have some sort of guide or rail system to keep the two halves in line with each other; otherwise, the platforms will twist relative to each other and quickly stop levitating. I used two small posts on the bottom platform that went into two bearings on the top. Magnets around the perimeters. Works well....

Thanks Cab!

I was just looking at a commercial product that uses the guides.  Don't horizontal movements generate contact between the platform and the guides?

I was imagining that having some magnets placed to attract each other would help to avoid the instability issue.  But the more I think about it, the sillier that seems.

Chad

[BobM]

Magnets are also not a good thing to have around interconnects and powercords, so placement and spacing is important.

Enjoy,
Bob

[JoshK]

Magnets are also not a good thing to have around interconnects and powercords, so placement and spacing is important.

Enjoy,
Bob

And a host of other things too like tubes, other magnetics, cartridges and arms, etc.  Plus the isolation is only one way.  It is no gaurantee that self-generated electro-mechanical vibrations in the isolated component has a low resistance place to go.  Then what about acoustical vibration?

[Mariusz]

Though about implementing that idea ones before but droped it for above mentioned reasons.
To many tubes and TT in my crib but it might work on transports and CDP.....if designed smartly.

Mariusz

[cab]

Earnshaw's Law, yes, that is what I was referring to...

In my system, the rods/bearings are extremely low friction and the platform indeed floats rather nicely. On top of the platform I have some dished stainless pucks with bearings  that I also made. This gives plenty of isolation.

The interesting thing about the magnetic isolation is that it is not a linear damping system, like springs or other "normal" damping systems. The compliance increases with the square of the distance, unlike a regular spring, which increases at a constant rate...

I have been very happy with the results. I have not had any issues with the transport it supports. I am planning on switching to a hard disk solution in the near future and suppose this rather interesting piece of hardware will end up in the closet...

[jeffdavison]

http://www.6moons.com/audioreviews/yamamoto3/footers.html
http://www2.117.ne.jp/~y-s/MGB-2-new-E.html
http://www.venushifi.com/products/yamamoto_audiobases.shtml

[JoshK]

P.S.  you shouldn't be intimidated to post in the lab.  I don't intend for the lab to be exclusive to those who already know a great deal of technical stuff.  They probably don't need the lab to answer questions.  The point is to learn and to share ideas. 

I feel like I should break out into koombyya.   

[chadh]

P.S.  you shouldn't be intimidated to post in the lab.  I don't intend for the lab to be exclusive to those who already know a great deal of technical stuff.  They probably don't need the lab to answer questions.  The point is to learn and to share ideas. 

I feel like I should break out into koombyya.   

Thanks Josh.

But if there's one way to keep people OUT of the lab, it's probably singing Kumbaya!

Chad

[Bill A]

I plan to build one at some point, but I wonder at the concequenses of having multiple components in a mechanical system, all with different resonant frequencies.  I'm thinking isolation platforms in TT setups here.

The interesting thing about the magnetic isolation is that it is not a linear damping system, like springs or other "normal" damping systems. The compliance increases with the square of the distance, unlike a regular spring, which increases at a constant rate...

Well, after thinking about this, I guess a system with non-linear damping has no resonant frequency, so that may not be a problem.


Bill

[BPT]

Check out the Clearaudio Magix http://www.clearaudio.de/. I believe they are the only magnetic isolation device that does not use guides. It is a true floating isoaltor. They get around the guides by using concentric ring magnetics. Each device only holds about 10 lbs. so they are best used for lighter weight gear. They do work. I have tried many types of isolation and the Magix allow extreme low level detail to be heard that other isolators obscure.
Chris H.