Mudcat

Mudcat

Senior Audioholic
While playing with a broken hard-drive this morning, I noticed that I could not force the two magnets together, very strong stuff obviously. So I thought about making a platform for my turntable - sort of levitate it. Before I go breaking a couple of more hard-drives, has anyone ever tried anything like this. Any thought on how the strong magnetic field will affect the cartridge, motor, signal processing?

Currently I use a massive butchers block sitting on four 8 inch OD inner tubes with four more tubes on the four sides keeping the block from hitting the cabinet walls. The tubes are all interconnected to a single valve for keeping the pressure the same in all 8 tubes. Now I want to levitate my Music Hall MM5 above that with these magnets (all just for kicks).

Or any other component for that matter too!
 
3

3beanlimit

Junior Audioholic
As far as I know, a true levitating platform has never been done with plain ole magnets and nothing else..

You need something to keep it from sliding off axis.

I've tried a few experiments on my own and can't find the solution. I've even read that it's not possible without using a computer and electromagnets to keep the platform stable but I had to try anyway. After all......neodynimum magnets aren't very expensive for the size you need.

Here's some examples of what you could do though as a diy....

http://www.gr-research.com/levitator.htm

http://www.tnt-audio.com/accessories/relaxa1_e.html

This should give you some ideas......

You could use plexy glass or even some MDF....
 
Mudcat

Mudcat

Senior Audioholic
Great articles, thanks. My plan was to use 8 magnets in much the same way I'm using the 8 inner tubes. Four mags for lifting, and four arranged on the four sides to prevent longitudinal and lateral movement. If the platform wants to spin maybe I'll just figure out how to make it spin a 33 & 1/3 and just use a tone arm attached to the cabinet. :p
 
WorkerBee

WorkerBee

Junior Audioholic
That is such a cool idea. :D I cut my wifes wrist rest into 1" squares and the jelly substance inside is a challenge to work with but is also just right for my DVD player. Found using heavy kitchen shears will cut the jelly substance pretty easily though. Using the magnets is a VERY interesting idea as long as the final project does not look like Grannys old rickity moonshine still. Didn't notice if the other guy recommended it but Parts X-Press has a bunch of those magnets.
 
Last edited:
WmAx

WmAx

Audioholic Samurai
Mudcat said:
While playing with a broken hard-drive this morning, I noticed that I could not force the two magnets together, very strong stuff obviously. So I thought about making a platform for my turntable - sort of levitate it. Before I go breaking a couple of more hard-drives, has anyone ever tried anything like this. Any thought on how the strong magnetic field will affect the cartridge, motor, signal processing?

Currently I use a massive butchers block sitting on four 8 inch OD inner tubes with four more tubes on the four sides keeping the block from hitting the cabinet walls. The tubes are all interconnected to a single valve for keeping the pressure the same in all 8 tubes. Now I want to levitate my Music Hall MM5 above that with these magnets (all just for kicks).

Or any other component for that matter too!
Like anything else, the assembly will have a resonant frequency and act as a low pass filter at a specific frequency, passing mechanical energy below that frequency and filtering it above. You will have lto find the optimum combination with the magnets to achieve a sufficient spring. The innertubes, since they are varied with air pressure, are easy to tune the frequency at or near the limits of the audioband -- so the intertube is actually an excellent means of mechanical decoupling considering it's *easy* adjustment.

-Chris
 
3

3beanlimit

Junior Audioholic
WorkerBee said:
That is such a cool idea. :D I cut my wifes wrist rest into 1" squares and the jelly substance inside is a challenge to work with and is just right for my DVD player. Using the magnets is a VERY interesting idea as long as the final project does not look like Grannys old rickity moonshine still. Didn't notice if the other guy recommended it but Parts X-Press has a bunch of those magnets.
They do....

Look here..

http://www.gaussboys.com/default.php


Again, I've tried two designs I've come up with and can't get it to level exactly or some way to keep it in line without some kind of "coupler" like the rods in the examples I've listed above.

Level...if..your DVD player, turntable, ect ect has it's weight spread evenly, then it's not a problem. Or......if it's close and it "sinks" pretty low, then it works ok as the magnets will repel pretty equally if their gap is pretty close.
 
B

bpape

Audioholic Chief
Tradeoff

Not to be a wet blanket here...

You do realize that while you're on the road to creating a device to perfectly isolate the platform from anything structural, you're actually making the airborne vibrations MORE of a problem since there is nothing to physically damp them.
 

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