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Post by jandl100 on Aug 23, 2014 6:31:32 GMT
Magnetic levitation  A recent eBay purchase - 4 footers with opposed magnets which allow kit to literally float on air.  See details and review here www.stereotimes.com/acc083109.shtmlI got heavy duty ones, designed to support 5-8Kg per footer. Under my vintage Technics cdp they didn't do much, really. And I had to weight the CDP down or the player wasn't heavy enough to push the top magnet down!  There's not enough shelf headroom for them placed under my Mingy Dah valve amp, so that was a no-goer, too.  But a couple of days ago the Minging One was set aside as I felt a sandy urge and my NAD S300 amp was re-installed. It floats perfectly on 3 of the footers.   Look closely at the footer on the left in the next pic and you can see a small gap between top and bottom parts - that's the air the amp is floating on - amazing!   Lightly touch the amp and it rocks. Just floating on air, man, floating on air. OK - the internals of the footer have to be exerting lateral pressure and touching the outer 'skeleton', you have to stop it sliding off somehow, but it must be very well isolated from shelf borne vibration. Soundwise, unlike the Techie cdp I hear a big improvement with the amp. Imaging is way more 3D and err, hanging in space  - like the amp!  Everything sounds a lot more real and present and solidly grounded. There's a more subtle and detailed portrayal of small scale dynamic changes. Dare I say that it makes the NAD sound a lot more like a good valve amp? Although why it seems to have an effect on kit without moving parts (the amp) but little or none on a wildly vibrating CD spinner is a matter worthy of some thought!  All in all I am most pleased with this little purchase. |
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Post by ChrisB on Aug 23, 2014 6:55:51 GMT
Interesting, Jerry. I would guess that you might need to ensure that they are placed so that they each share a fairly equal proportion of the weight, or there could be problems with too much side pressure? Is there any facility for levelling?
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Post by MikeMusic on Aug 23, 2014 9:36:33 GMT
The idea of floating in space has to be good
Any details on what the magnetic fields might do, short or long term ?
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Post by Paul Barker on Aug 23, 2014 13:35:20 GMT
How about the cd player has self generated noise which would swamp anything coupled through the supports so the real problem of the cd player can't be fixed by this, except to mount the electronics of it seperately.
The ultimate for the rest would be to have triangulated side thrust magnets with opposing partners on the equipment to position the equipment laterally, then place free standing magnets beneath (opposing magnets stuck to equipment).
No touch in any dimension.
Magnets powerful enough to do the supporting element are very costly, beyond reason for a boatanchor valve amp.
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Post by jandl100 on Aug 23, 2014 17:45:58 GMT
Interesting, Jerry. I would guess that you might need to ensure that they are placed so that they each share a fairly equal proportion of the weight, or there could be problems with too much side pressure? Is there any facility for levelling? No, no facility for levelling - you just have to place the footers carefully. It worked well with the NAD amp as the main contributors to the weight are two massive transformers bolted to the front plate, and the chassis, so it's quite symmetrically balanced.
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Post by ChrisB on Aug 23, 2014 17:49:00 GMT
I see, thanks.
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Post by jandl100 on Aug 23, 2014 17:49:41 GMT
How about the cd player has self generated noise which would swamp anything coupled through the supports so the real problem of the cd player can't be fixed by this, except to mount the electronics of it seperately. The ultimate for the rest would be to have triangulated side thrust magnets with opposing partners on the equipment to position the equipment laterally, then place free standing magnets beneath (opposing magnets stuck to equipment). No touch in any dimension. Magnets powerful enough to do the supporting element are very costly, beyond reason for a boatanchor valve amp.
Ah, interesting - maybe that's why I heard no improvement with the CD player.
The footers I have are specced to support up to 32KG if using all 4, so most amps would be OK I would have thought. If the amp is heavier, you just need more footers!
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Post by Paul Barker on Aug 24, 2014 6:42:48 GMT
32kg is impressive, but avery light boatanchor.
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Post by Paul Barker on Aug 24, 2014 11:38:19 GMT
Friends and I used to make boatanchors which would weight 50kg upwards. In reality there isn't a lot of point doing that, but we had fun.
Personally I go for lower powered valve amps these days.
The levitation support concept has always interested me. A friend back in early 2000's who called himself Jack of all on forums played me his bottlehead 45 amp on a compressed air type support. I think it was called seismic sink or something. I couldn't fault it at all.
ALways wanted to try and emulate it in diy ways, never got it off the ground. So many ideas so little time.
Would probably achieve magnetic levitation more easily.
As stated above though, I rather fancey no points of contact whatsoever.
But if it did have the side contact as in these commercial ones I suppose it wouldn't be too bad if made of teflon, or lubricated with grease or oil, or maybe ball bearing guided.
I would favour three point lateral opposing flux magnetics.
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Post by Paul Barker on Aug 24, 2014 11:46:16 GMT
field coil magnetics isn't out of the question with regulated direct voltage supply to each unit adjustable to level the equipment. Maybe the equipment have three nib magnets, the stands basically a solenoid. the lateral forces corrected with laterally mounted solenoids, again working against nib magnets, again adjustable to balance in space.
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Post by Paul Barker on Aug 24, 2014 11:54:04 GMT
People will be saying why bother with making solenoids. Wellthis is why. The cost of sufficiently powerful permanent magnets is a sufficient obstacle to make it worth looking into. I know from field coil speaker motors that active magnetics is no second cousine, rather a superior method. there is no limit to the power and it doesn't degrade over time. The only cost is the time to wind a circular coil and a lump of iron, say turned from motor armatures for example.
Though the solenoid from a starter motor would be probably tailor made for the job. Only problem is obtaining them at reasonable cost. For light equipment the solenoid from washing machine fill valves would be adequate and very cheap.
I would probably make my own as I am equiped.
One more diy project on the long list.
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Post by gazjam on Aug 26, 2014 13:09:19 GMT
Wonder what potential effect magnetic fields may have on the electronics it supports?
What you gain in one area you lose in another?
RF/EMI is usually a big no-no!
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Post by Paul Barker on Aug 26, 2014 16:05:58 GMT
RFI and emi are ac signals. The flux of the magnet not moving is constant. It is not affected by signal and doesn't affect signals.
The flux from ac magnetic components inside the amp do cause interference because they change.
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Post by Paul Barker on Aug 26, 2014 18:01:41 GMT
Ok I'll make it a project. Just as an experiment to see how much strength they contain I have ordered 6 of These nib magnets to make a powerful tripod and 2 of these ones out of which I could make a lower powered tripod after dismantling them (and have two spare magnets). So I shall report back what weight the two different types oppose. To keep it simple will not use the tripple lateral method on top of the triple weight bearers. So i shall have to turn some tubing to house the magnets in and some pistons. It occurs that to make the lateral friction less I could fill the tube with hydraulic oil. This would of course modify the method to a damped version. Or I could use just a polished finish, or I could use teflon. Time will tell. |
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Post by Eduardo Wobblechops on Aug 26, 2014 19:51:48 GMT
Interesting Paul, be good to know how it turns out.
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Post by ChrisB on Aug 27, 2014 20:34:02 GMT
As long as you understand that I'm not necessarily condoning this behaviour.............!
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Post by jandl100 on Aug 28, 2014 6:00:22 GMT
Haha! Amazing. I want one!
I see it's set up as a pseudo-Omni ..? So I guess the forces/reaction from the sound waves balance out, and it doesn't try to escape the mag field. Would be most interesting to hear one.
Is the levitation just a lifestyle thing, or does it affect the sound?  |
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Post by ChrisB on Aug 28, 2014 6:14:13 GMT
You can configure two for stereo, I see. I was wondering how it might cope with a bad draught or breeze!
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Post by Paul Barker on Aug 28, 2014 20:25:14 GMT
I suppose the base is a ring of magnets the sphere won't be able to escape the circle. Wind wouldn't have the power, the sphere would offer little to catch the wind and the mangetic forces would have plenty of influence.
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Post by ChrisB on Aug 29, 2014 7:32:46 GMT
Another trinket.....
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- like the amp! 
