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magnetic sheidling for sl1200's


DavidBanner

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I need to make some sort of cover for an SL1200, so that I can plonk my laptop on there and not worry about the TT getting turned on and scrambling my HD. I'm currently using a bit of foam, which works great but I'm in constant fear of the TT power being switched on.

The foam works great as it's flexible, works as more protection for the laptop in the bag and keeps everything nice and stable, so I would like to keep this aspect and maybe glue a flexible layer on the top of the foam..

- any ideas?

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I could be wrong about this but I think SL's are already shielded... I'm sure I remember seeing a foil lining inside there and I don't think it's just cause the designers like shiny things ;) Of course, that's nice, but the platter itself is subject to magnetism so I don't see any way around that.

You might find it easier to shield the disk drive than the deck....

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just for clairty as I've just got back from a tour so my head is still foggy and I might not have made things clear:

the idea is to put "something" on the platter  of a 1200 as a sheild and then the laptop goes on top of that "something"

the SL1200 has a metal platter and a rather beefy looking electomagnet around the spindle.

My laptop will be sitting pretty much dead center over the electro magnet.

Also the HD in my laptop is my primary concern, so sheilding that is not really going to be very easy. I know the ideal solution is probably a Faraday cage; but I can't get my head round a practical application.

of course in an ideal world every club would have 2 of the stands Mike B suggested (one for the lappy one for the controller) - but that's never gonna happen; even with a technical rider (I've turned up to gigs in some countries with a bag of records to find they don't even have turntables, just CDs!).

The other issue is speed - I need to be setup asap. When the gigs are tightly timed I often only have a few mins after arriving at the club from the last gig before I need to take over...

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Heya DB!

Think sandwich: thin sheet metal plate, foam on top + foam on bottom, metal plate a few inches smaller than the foam (soft edges), held together with some spray mount adhesive. (wont degrade most foam)

Magnetism on this order usually needs a little more than thin metal foil/copper tape like used for rfi.

Sometimes I almost miss repairing open-frame arcade game monitors.... ;)

Best

Smash

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using a compass perhaps??

This would be the cheapest way.

Another way would be to use a selfbuild "detector". Just a ring out of metal (10-20 cm diameter) with a shielded cable connected to your multimeter.

The ring acts like a detector for magnetic fields. I could swear I saw something like this before ... must find the plans again.

greets

Doc

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... don't mix up rfi with magnetism.

To shield magnetism, you can't just use any metal plate, it has to be a ferric plate.

Just test it:

Take an alluminum plate, hold two magnets on both sides about 1/2 Inch away from the plate and you'll see (... or better: feel), that the magnetic field goes almost unhindered through the alluminum.

Do the same with an iron sheet metal plate... you'll see.

Greets, Roger

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Whoops yeah I should have been specific.....too many years here in the US where the term sheet metal implies some sort of Steel formula.... ;)

The ring detector thing works well, but beware that it has a relatively limited bandwidth, similar to a tuned antenna, where a real gaus meter built/tuned for mag (and related harmonics) will show reality.

I made the mistake once of mentioning using DSP to tweak harmonic attenuation in real time to a tube amp pro buddy of mine.

He whipped out some notes from his past days doing scalar EM lab research.....one look at the math involved on just the harmonics side of EM caused both of my remaining brain cells to hurt, and made me happy to be "just an audio engineer" with only standing waves, resonant frequencies, and air temperature to cope with..... ;)

Whoop sorry to ramble!

Best

Smash

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hello

      i dont know if this will help but you can get this stuff called mylar silver one side gold the other flexible like plastic it was designed to shield satellites in space i know it shields from radio frequencies and radiation not shure about magantism but maybe as its just another em wave its available very cheaply from hydroponic grow shops as growers use it to line grow rooms reflects light into room shields from infra red detection if you get it the right way round  also good way to protect computers from em pulse so if you wrapped your laptop in it it would still work after anuclear blast as long as it not a direct hit anyway hope this helps 

                                                        kris

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steel which seems to be the only alternative....

... watch out with steel! Steel only works, if it's got enough iron. High grade inox steel has lots of Cr and Ni in it, which makes it non-magnetic and as a result, it's also not really shielding magnetism anymore. Best is: Cheap iron sheet metal. - Paint it to prevent corrosion.

Greets, Roger

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oh well its still good to protect your computer from a nuclear blast] oh well its still good to protect your computer from a nuclear blast

but only if you've got the mylar grounded. but to be honest I think i'd be more worried about my skin falling off and the crowds of cannibal looters than firing my laptop up....

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Hah it's a bit like that on any planet inhabited by homo erectus. If I'm unfortunate enough to be around post armageddon I'll be stretching goatskins over wood. I learn from my mistakes ;)

I was thinking though... If the turntable has enough room to reach the back and mount a record, the laptop would have a fair bit of separation - is the magnetic field still effective at that height? Might be worth trying smash's trick ...

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I live in East London, so every day/night can be a scene from 28 Days Later.

and then

My studio has 4 clubs within 20 seconds walk from the door, one of them has a party that starts 7am Sunday Morning... So you can imagine the state of the people I see when I come to the studio on a Sunday at kicking out time!!

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