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DIY => DIY Audio => Topic started by: vinyljan on April 13, 2014, 04:53:12 PM

Title: "Rollerblocks" DIY
Post by: vinyljan on April 13, 2014, 04:53:12 PM
I wanted to try Rollerblocks of some sort as feet for a DIY turntable, but I'll have to outsource or buy. But then I got an idea while browsing in a toy store (another story altogether).
(http://i62.tinypic.com/16c9h1t.jpg)

Pic is of the base of the tt, therefor upside down. Drilled 4 holes and cemented the magnets in place. Metal ball attaches and repositions itself in the middle. When the turntable is touched it moves quite freely, only to return to the original position after a few bounces. Might actually be a bit irritating when not used to, but as it is positioned on top of an old cabinet I going to give it a try
Title: Re: "Rollerblocks" DIY
Post by: DeonC on April 13, 2014, 05:30:45 PM
OK. color me impressed! That was very smart thinking. :2thumbs: I might just have to steal that idea... :point:
Title: "Rollerblocks" DIY
Post by: Hi-Phibian on April 13, 2014, 06:49:40 PM
Interesting. Trying to evaluate the magnetism thing vs cup and freedom of movement (very important) in my head.



If a serious bump were to break the magnetic bond is there anything stopping the TT hitting terra firma?
Title: Re: "Rollerblocks" DIY
Post by: vinyljan on April 13, 2014, 07:26:14 PM
I think the power cord and arm wires will have quite an effect on freedom of movement once connected. Metal spheres are 12mm diameter and the magnetic bond is amazingly strong to disconnect, but allows the ball to roll quite freely, but the further away it moves from the magnet's centre, the more the magnetic effect to centre it again.   
Title: Re: "Rollerblocks" DIY
Post by: Hi-Phibian on April 13, 2014, 07:32:16 PM
Which is exactly like a cup. The ratio of curve and ball radius is of great importance according to the roller block developer.  Thus the magnetic strength would be too.
Of course roller blocks do not isolate, they only provide an energy drain for what gets in the device and is made by the device.
Title: Re: "Rollerblocks" DIY
Post by: Hi-Phibian on April 13, 2014, 07:35:22 PM
I quite like it. What toy is it based on?

Some simple rimmed metal cups like bottle tops or similar would enhance safety. Only minimal movement is needed as long as it is free.
Title: Re: "Rollerblocks" DIY
Post by: Kemosabe on April 13, 2014, 10:21:10 PM
When it comes to buying or fabricating a roller block type solution what options are there?
Title: Re: "Rollerblocks" DIY
Post by: Hi-Phibian on April 13, 2014, 11:41:29 PM
Roller blocks by symposium and cold ray by, cold ray...
Title: Re: "Rollerblocks" DIY
Post by: Kemosabe on April 14, 2014, 03:05:04 PM
Roller blocks by symposium and cold ray by, cold ray...
And what would those of us without $350 to spend on a few steel balls do?
The steel balls are obviously quite easy to get.
What about the little hollow that holds them - a bit less easy.
Title: Re: "Rollerblocks" DIY
Post by: GearSlave on April 14, 2014, 04:16:36 PM
If a serious bump were to break the magnetic bond is there anything stopping the TT hitting terra firma?

I think the power cord and arm wires will ...   

 :ROFLMAO: :ROFLMAO: :ROFLMAO:
Title: Re: "Rollerblocks" DIY
Post by: DeonC on April 14, 2014, 05:07:03 PM
These guys, Magnets 4 u (http://magnets4u.co.za/) have some really nice rare earth magnets in their catalog (http://magnets4u.co.za/downloads/Magnets4u_cat2013.pdf). They have some shallow pot rare earth magnets (19mm, 28.5mm and 38mm dia.), deep pot rare earth magnets as well as rare earth magnet discs. They just don't have prices on the site, but these seem like they would be just what the doctor ordered. :thumbs: Those rare earth magnet pots have their N-pole in the middle and the S-pole on the edges. I think that should be ideal, but then again, I was never any great shakes at physics. What you you guys think?

Deon
Title: Re: "Rollerblocks" DIY
Post by: DeonC on April 14, 2014, 05:38:19 PM
Here are some very nice magnets from Magnetech (http://www.magnetech.co.za/):
Neo Disc 22x20mm N38 Ni
Code: M-ND-D-N38NI07
Quantity in Stock: 55
R 86 each
(http://www.magnetech.co.za/Images/Neo%20Disc%2020x20%20W.jpg)
Title: Re: "Rollerblocks" DIY
Post by: vinyljan on April 14, 2014, 07:42:23 PM
:ROFLMAO: :ROFLMAO: :ROFLMAO:
:facepalm: " I was misquoted"  :BWAHAHAH:.,when I first tried it, it was with the turntable base without any wires, and it moved quite a lot. It will be less with the arms etc included, same with rollerblocks.
The magnets are neodymium, 10mm diameter and cost R12 each, metal balls diameter 12 mm diameter,  R4 each. Not part of any toy, it's one of those science projects shops. To pull these apart is not easy, 2 magnets stuck together can only be separated by sliding apart. Honestly don't think it will come apart by/due to an accident.
Milling or finding something to use as a hollow cup that is perfectly smooth and hard enough for a heavy plinth  :thinking:, difficult
Title: Re: "Rollerblocks" DIY
Post by: Hi-Phibian on April 14, 2014, 07:49:09 PM
Going through the trouble of a proper cup would defeat the simplicity of the magnets and make them redundant.


Perhaps just an o ring larger than the ball, placed on the support surface surrounding the ball will stop a free roll.
Title: Re: "Rollerblocks" DIY
Post by: Kemosabe on April 14, 2014, 08:48:26 PM
Strong magnets anywhere near your cartridge may not be good. I know someone who can detect 4 fridge magnets brought to withhin 1m of the tt.
Title: Re: "Rollerblocks" DIY
Post by: vinyljan on April 14, 2014, 09:00:17 PM
Strong magnets anywhere near your cartridge may not be good. I know someone who can detect 4 fridge magnets brought to withhin 1m of the tt.
DOn't know enough but this might be a valid point. :thinking:,any opinions?
Title: Re: "Rollerblocks" DIY
Post by: skollie on April 14, 2014, 09:48:53 PM
Fridge magnets are made from ferrite and are low flux. Some can barely hold a small sheet of scrap paper against a fridge door.

mafioso
Title: Re: "Rollerblocks" DIY
Post by: SeanS on April 14, 2014, 09:56:34 PM
Fridge magnets are made from ferrite and are low flux. Some can barely hold a small sheet of scrap paper against a fridge door.

mafioso

But those neodymium magnets are another story.. I have some on the fridge that the kids can't remove. Not sure they belong near a TT.
Title: Re: "Rollerblocks" DIY
Post by: Hi-Phibian on April 14, 2014, 10:10:23 PM
We were having such fun with rolling voodoo I did not want to distract.
I for eg do not use strain relief springs on RCAs as that is magnetic steel. Imo audible for worse,
Then again there are arms with magnetic anti skate and even magnetic arm bearings
Title: Re: "Rollerblocks" DIY
Post by: DeonC on April 14, 2014, 10:15:29 PM
Some of those magnets from Magnets 4 u come in their own pods. Also remember that neo is basically self-shielding in a sense. I guess that is because they are so focused, but neo-magnet speakers do not interfere with CRT monitors and TVs.

I am starting to think those Magnets 4 u magnet pods would be the ideal solution- both poles are at the bottom, so there should be very little stray magnet fields above them. Someone willing to contact them and get some prices?
Title: Re: "Rollerblocks" DIY
Post by: chris on April 14, 2014, 10:27:45 PM
Just send Rob a e mail he will get back to you in no time. I buy a lot of magnets from them and always had good service.
Title: Re: "Rollerblocks" DIY
Post by: Kemosabe on April 14, 2014, 10:49:19 PM
For the record I didnt believe the magnet story I was just relaying it. I am not sure they were fridge magnets by the way they were being used to hold up some fairly weighty cardboard so could have been more powerful.
Title: Re: "Rollerblocks" DIY
Post by: chipwelder on April 17, 2014, 02:29:47 PM
Creatively using 3 ball and magnets might get you enough distance?... but I do think the weight of the TT, will be more than a match for the magnets... momentum and all
Title: Re: "Rollerblocks" DIY
Post by: Kemosabe on April 17, 2014, 02:39:05 PM
Sorry for being dumb but I dont get this magnet solution. It's nothing like rollerblocks where the weight of the tt or other component actually pulls the component back down after a shock. Magnets hold on and when they lose their firm hold that's it your turntable is going over onto the floor. And given they hold on so tight while they are in control how is this going to sink the energy in the system?
Title: Re: "Rollerblocks" DIY
Post by: vinyljan on April 18, 2014, 12:00:18 PM
View My Video (http://tinypic.com/r/2u7yjjr/8)
Title: Re: "Rollerblocks" DIY
Post by: vinyljan on April 18, 2014, 12:15:56 PM
Sorry for being dumb but I dont get this magnet solution. It's nothing like rollerblocks where the weight of the tt or other component actually pulls the component back down after a shock. Magnets hold on and when they lose their firm hold that's it your turntable is going over onto the floor. And given they hold on so tight while they are in control how is this going to sink the energy in the system?
Wasn't sure the video was going to load. Weight of the base of the tt is about 5kg, 4 balls on 4 magnets.
(http://i61.tinypic.com/17ej69.jpg)