[sci.electronics] Inquire: Need electromagnetic shielding.

ornitz@kodak.UUCP (barry ornitz) (02/03/88)

In article <896@houligan.UUCP> equacken@houligan.UUCP (Eric Quackenbush) writes:
>Can anyone tell me how I might shield electromagnetic fields from one audio 
>component to another?  If I place my amp too close to my pre-amp, I pick 
>up a hum.  This is a problem since my equipment is rack mountable and I 
>need to run it in this configuration.  I'm fairly sure this can be done 
>since I have seen shielded speakers.  I have posted in rec.audio but have 
>yet received any responses.  Any replies will be greatly appreciated.

For magnetic shielding, you might consider one of the high permeability
mu-metal alloys.  Looking in my "Interference Technology Engineer's Master"
and in my "Electronic Buyers Guide", you might try the following companies:
   Ad-Vance Magnetics, Inc.                     219/223-2368
   Perfection Mica Co., Mag. Shield Div.        312/766-7800
   Eagle Magnetic Co., Inc.                     317/297-1030
   MuShield Co.                                 617/321-4410

The material you are looking for is not cheap and these manufacturers may not
sell in small quantities.  If you can afford to waste your money on Monster
Cable, etc., you can spend it here too.   ;-)

BTW, the main reason I (and I assume others, too) stopped posting replies to
rec.audio was the fact that most rec.audio readers are incapable of under-
standing any science, and instead take their hobby quasi-religiously (OFHC
Litz wire, Monster cable, RCA plugs, and mercury-filled speaker wire come to
mind).  I guess I owe it to sci.electronics to go back (and take jj@alice
and Larry with me) before this group becomes overrun with questions worse than
how do I clean my coffee maker [sci.electronics answer: plasma etch]. ;-)

Eric, don't take the above comments personally.  You have a valid question and
I hope one of the above companies can help you.  If the rest of the wreck.audio
questions were like yours, I would have never unsubscribed.  Good luck.
                                                                Barry
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