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Old 19th November 2012, 09:36 AM   #241
dady is offline dady  Argentina
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Default This are more details with the plans.

You can see the coup attached to the bearing, the axle inside with the upper magnet, and finally the turntable working. The original platter weight 3Kg, I make a form in plaster and with this I make a mold or external copy in the same material I melt 30kg of lead and I glue to the platter bell. After that I machined in a turn machine and balanced it. The weight rise until 26Kg, to much. Recently I remachined that until a weight of 16kg and balanced again.
I polish the axle and not any rumble at all. I conserve yet the vacuum original properties from the original platter (the axle is perforated) and I add the property aircushion with magnetic suspension.
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Old 19th November 2012, 11:39 PM   #242
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Default Ring magnet source

There is a source of ring magnets that seem to have been overlooked here.

Microwave ovens.

The "magnetron", (What we call the vacuum tube that produces the microwaves here in the US), is easily removed from a broken Microwave oven, and each Magnetron uses two ring magnets. They are quite powerful, and easily removed from the Magnetron. Usually, however, one ring magnet is larger than the other.

If you don't mind finding a source if junked microwaves, you should have a virtually inexhaustable source of nice ring magnets.
Oh, and the north and south poles are situated on the faces, giving you quite a repelling force.




Quote:
Originally Posted by AuroraB View Post
Your easiest source of ring magnets, are blown ( or new ) bass or PA loudspeakers. The description of the "Platine Verdier"


published in l'Audiophile in the late 80's, called for large loudspeaker mag's encased in turned polepieces to increase the field strength.
I started this project many years ago, but it came to a halt when I could not find suitable magnets without buying new and expensive speaker units - as I live in rather rural areas, my sources of "interesting scrap and junk" are quite limited.
If your platter is of reasonable weight, this could be fairly easy. .the Verdier platter I started was over 10 kg's....

EDIT: the bearing for the Verdier, was essentially a combination of the magnet cushion and an inverted bearing, as the platter was also resting on a steel ball on the top of the steel shaft, to take a minor part of the load. Personnally, I think the idea of no true radial bearing is totally futile, given our demands for platter stability.
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Old 23rd November 2012, 06:28 AM   #243
dady is offline dady  Argentina
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I think for avoid the strong field that interact with the tonearms and magnetic cartridges the best is put a long axle on the botton, the problem here is a long axle with a heavy weight platter could play no good with bushes if not well balanced.
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Old 29th November 2012, 11:46 AM   #244
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Is there anyone that tried the magnetic link below, it looks similar to Clearaudio CMB Bearing.

Click the image to open in full size.

Custom Maglev bearing for turntable | eBay



This one is a recently developed magnetic platter system by Clearaudio.

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Clearaudio Magnetic Platter
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Old 17th December 2012, 11:42 PM   #245
YNWOAN is offline YNWOAN  United Kingdom
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Hmm.....

recently developed......


Ahum!
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Old 19th December 2012, 07:35 PM   #246
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Maybe , it's just taken them a long time to build what diy-ers have been doing fro ages.
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Old 21st December 2012, 02:30 AM   #247
sregor is offline sregor  United States
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Quote:
Originally Posted by AuroraB View Post
<snip>
The use of a spindle bearing handling the side load only, and magneitc repulsion in the vertical, I beleive was first seen in the "Platine Verdier" late 80s....
TEAC TN-400 in the mid 70's. Before that I believe there was a Stanton or Pickering TT.
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Old 24th December 2012, 01:13 PM   #248
pdm4606 is offline pdm4606  United States
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Default platter support

The real trick of course would to completely suspend the platter in all planes.
I remember years ago that some ingenious fellow suspended his platter in a pool of mercury. I can't imagine the benefit. The mercury would transmit and side motions and
possibly motor vibrations, wouldn't it?
This was reported around the late 50's. I never heard of it again.

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Old 17th March 2013, 10:37 AM   #249
Bibio is offline Bibio  Scotland
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here is an idea for you all to think about.

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Old 17th March 2013, 06:12 PM   #250
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I'll save you some trouble, no one has even been able to manufacture a stable radial magnet bearing. Lot's have tried. Just suspend it vertically.
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