zero cost magnetic isolation

could be problematic if you have a tt or a pacemaker

 

good point....?....

 

Hmm, maybe maybe not ... I installed one of the new Clearaudio decks with the opposing magnet bearings last week ... It sounded superb ... Those magnets are nowhere near as strong as you would need to float a heavy piece of kit as they are only holding up the platter and don't actually float it anyway, just take a large part of the pressure off ... on the other hand they come within centimetres of the cartridge at the end of side to no apparent ill effect.

 

http://stores.ebay.co.uk/Scuddlebutt3_Ferrofluid_W0QQcolZ4QQdirZ1QQfsubZ1927014QQftidZ2QQtZkm

I don't know what the base fluid for that is, but if you email and ask they may be able to tell you. Silicone is a popular base material and would also be suitable for this application.

 

opinion revised !

 

well like I say, maybe maybe not ... they are weaker but come pretty close to he cartridge. DIY HiFi supply used to do a magnetic platform which was supposed to work fine with turntables

 

Experience beats paranoia

Glad to hear that magnets appear not to cause any ill effects. My question was simply a question, not a suggestion that there would be a problem, and it's good to hear some results that help answer it.

I look forward to hearing how more energetic people than I get on with developing this idea.

Best wishes

 

Hmm well I'm not sure that it wouldn't possibly cause a problem. To levitate the platform and a turntable for example would require far stronger magnets than to take some of the weight off a platter.

 

That's all when all good if the base is not loaded or under full load. Move the base a couple of millimetres either way and the magnets do all sort of strange things

How about using the magnets with a hole through the centre and using a low friction PTFE rod vertically through all the magnets for keeping it on track?

 

This is what i suggested except using nylon rods as it is more rigid than ptfe.

 

I didn't actually know which was more rigid Dom, the PTFE or the nylon, I was just looking at the friction properties of the PTFE. How about PTFE tube/sleeving over a brass/steel rod?

 

how about 4 ferrofluid dampers, one on each corner, and a magnet on each corner to act as a spring ?

or I guess you could have a base a bit bigger than the platform with four posts, then attach fishing line to each corner not enough to support the thing just to stabilise it. ?

can you not just hang the unit rather than float it? IE magnets on top ? might make it a bit more stable?

this would work but would need to be massive http://home.earthlink.net/~lenyr/levmag.htm ?

how about using air instead ?
just use the ball bearing / cone method, with a hole or holes in the cone where the ball meets it,use a fish tank air pump to blow air through it (using a large air reservoir and a sound proofed box to keep the pump quiet) and epoxy the ball in another cone upside down, fixed permanently to the platform?

 

Thats the way I'm going ....three 1mm brass rods with ptfe sleeve, a second sleeve will be used for the top floating plate.

as set up now....

the magnet is threaded onto the rod and a second magnet placed so that it opposes the first ....the top plate has a hole that the rod fits through and allows vertical movement. The top plate sit on the top [floating magnet]. The unit just works ..in that I have about 2mm of repulsion with my cdp sat on the top plate ...this give reasonable isolation across the freq range [using the stethescope] ..

how does it it sound ....it was immediately apparent that the bass had increased and some extra resolution ...this was using the quad 99 as dac only to my squeezebox3 ...

I'm going to add more magnets [currently using 3 pairs of 10 mm dia ] and see if I can get a bigger lift.

 

"can you not just hang the unit rather than float it? IE magnets on top ? might make it a bit more stable?"

If you mean to use magnetic attraction rather than replusion, I would have thought that the inverse suare law would mean you would never get the thing stable, the magnets would either stick together if they got to close or the suspended unit would fall to the floor if it got a little too far away.

Repulsion shoudl be the more stable solution since the repulsive force increases as the magnets get closer.

Aolologies if I misunderstood the suggestion.

 

probably right.

hey why not just buy this

http://www.bornrich.org/entry/magnetic-floating-bed-a-design-masterpiece/

you could put your speakers on there too

a commercial design http://www.cayinusa.com/Product_Name.asp?Category=28:60:49&types=1

 

Blimey, better empty your pockets before getting on that eh?

 

Has anyone found any calculations for the weight that can be supported by the magnets?

I would like to order some, but don't want to end up 'bottoming out' just with the weight of a shelf, or having to use 20 magnets to levitate. I think the nylon line securing corners is a good idea; each shelf would have to be tuned for tension and binding, dependent on weight.
Think of the fun; dress your LP12 arm cable, then dress its' support cables. Endless.

So, back on track, what strength magnets do we need for which piece of equipment. Ebay beckons.

Ian

 

Pete is this any use:

http://www2.117.ne.jp/~y-s/MGB-1-news-eng.html





10,000 yen each (what's that about 40 quid) - seems quite reasonable actually, though it'd be a fair bit more landed I'd guess.

 

That seems like a simple and effective idea Uncle Ants

This ebay seller has a good variety of neodynium magnets
http://stores.ebay.co.uk/PowerMagnetStore_Ring-Magnets_W0QQcolZ4QQdirZ1QQfsubZ12044083QQftidZ2QQtZkm

 

stretch a cut o ring between the top and bottom bit under tension due to repulsion and lock it in place with grub screws.