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I have searched the net for a small quanity of TI-Shield without success. It appears to be manufactured for large commercial projects. I'm gathering parts to build the old High Resolution Speaker Cable Filter (HRSCF) attributed to Al Sekela & Christopher da Costa. If I have the names wrong please correct and forgive me.
Anyone know of a source for small quantities of (12" x 12" or so) TI-Shield? Or a substitute?
Thanks to you,
Pixelphoto (Marvin)
Follow Ups:
Check AMAZON.COM they sell a lot of different shielding materials.
I bought from Michael Percy. Email me, in the mean time I'll try to find it and measure it.
E
T
et"at sign" econotweaks"dot" com
TI Shield works. I have bought it a few times from M Percy. However, Mike no longer carries it, and apparently for good reason: it seems to be defunct. So far as I can tell, TI (Texas Instruments, not "titanium") no longer makes it. That leaves you with a choice of mu metal or ERS cloth or both if you want to shield against both EMI and RFI. Did you have other information to the effect that it is still manufactured? I could not find such.
http://gavenindustries.com/RFEnclosures.html manufactures it for large commercial jobs.
Once M Percy told me he no longer carries it, I did embark on an internet search and I did find also where huge sheets of TI Shield are still made and used sometimes to line the floors, ceiling and all four walls of a room or a large container in which delicate equipment that needs shielding from RF is housed and used. The problem is TI will no longer market it in 12-inch wide sheets for DIY use, I guess. If I were obsessed with getting some, I would try to find an end-user of the large sheets and see whether one could get some small pieces from that beta source. You might try a military installation, for example.
and the little consumer.
Loved the 3M tube dampener, ( clear, poly rings, although I would use them elsewhere in a system). When they sold out they refused to make any more. Apparently the sheet stock was left over from some Aerospace project which got cancelled and unless I could spring a million bucks, that was it.
You would think such large manufacturers would have back doors....
nt
Yes sir. He is out of stock. No more.
what is a TI shield ( titanium?)?.
FWIW, I have bought magnetic shielding material from LessEMF.com. This included mu metal, silver impregnated cloth, copper foil, and that new Metglass in one inch wide strips..
Again, FWIW, magnetic shielding needs a copper lining to provide complete coverage.
unclestu, this is all fairly new to me. The recipe for the HRSCF calls for TI-Shield.
TI SHIELD: Unique composite shielding material from Texas Instruments for blocking EMI & RFI interference. Conventional shielding materials excel either in electrical conductivity or magnetic permeability, but not both. Steel is not conductive enough to be effective at blocking high frequencies, while copper and aluminum are not effective at absorbing low frequency EMI. No single material met both of these requirements until TI developed this copper/alloy 49/copper composite material. TI Shield is effective from below 10Hz up to 10GHz and is currently available only in .014" thickness (28-29ga). Counterpoint utilized sim- ilar technology in construction of their chassis' and found significant audible benefits were to be derived from surrounding audio circuitry with materials that shield against both EMI & RFI. Unlike Mu-Metal, this material may be cut and bent into conven- ient shapes without requiring annealing to restore its shielding properties.
12" x 12"/$32.50, 12" x 24"/$64.50, 12" x 48"/$127.00 --- NOT CURRENTLY IN PRODUCTION. From Percy Audio catalog.
Has anyone here built these speaker filters. Can you recommend a replacement material?
Check out sites manufacturing Mumetal and then review your high school physics texts. Many mu metal sites have superb application notes (Co nectic and others, do a google search).You are attempting to address EMF fields. That is Electro Magnetic Fields. ALL AC current generates both a magnetic and an electrical field property per Faraday's laws from waaaayyyyy back. The two fields are inseparable and this has been known for quite some time, although often ignored.
Counterpoint simply copper plated their steel chassis to address the E factor. but if you look back I can find samples of Harman Kardon's Festival receivers, and many other vintage tube gear which utilized copper plated steel chassis to address similar issues. You see lot of this in older analog radio tuner sections, too.
I have been using mu metal foil (10 to 15 mil) covered with copper tape (3M available at Digikey, Mouser, etc.) for similar effect and while not having compared it directly to the TI product have been satisfied with results. In fact, using the Mu metal/copper composite, allows me to make a layered construction for even more EMF reduction. Of course this requires experimentation and careful listening, but an understanding of the principles involved will more than amply reward you further down the road.
Though perhaps not quite as effective as mu metal or metglas as a base, covering most steel or nickel, or even brass helps sonics a bit. (transformer covers, ferrite beads, even strips under power transformers on top of chassis).
Edits: 02/27/15
Mu metal plate does not like to be bent. Much of its magnetic properties become lost in the crystallization along the point of the bend. I believe you want to keep the radius of the bend about twice the thickness. This is easily achieved with foil, though, and the copper tape easily conforms. Helps to ground the copper of course. Mumetal is affected by heat, although I have soldered pieces together to fabricate boxes (Algo Hamilton wanted $500 each for transformer potting cases If I bought 500 pieces !)Mu metal and any magnetic shielding, for that matter, does NOT like sharp 90 degree corners. Even a 45 degree angle snipe of flat sheet at corners helps, removing a slight upper frequency hardness.
The LessEMF.com website has a lot of weird stuff ( even for me, which is saying a lot). But read it very carefully, some of their application notes took me years to learn by trial and error. Don't look at their clothing line and laugh.
Edits: 02/27/15
unclestu,
From what I've gleaned so far is that I could use Mumetal Joint-Shield foil tape (4" x .010") which has an adhesive backing. And 3M copper tape 1181 1/2" (RFI/EMI shielding) and sandwich the two. The recipe calls for the shield to be 1.5" x 2.75" (project enclosure is 4"x2"x1") per filter and I plan on building six. So I'll build one and test, etc.
You can build a cylindrical main body and slip the internals in. Use the joint foil to deal the ends. IIRC the circuit calls for caps and resisters, place them in line with the main body as the EMF field generated is parallel to the body.
Enacom, a Japanese manufacturer, uses plumbing copper tubing and the matching ends to build a container . You could do the same and simply line the internals with magnetic foil. Just solder the ends to the copper shell, after sanding the shell clean and shiny and liberal application of rosin.
Thanks unclestu, your advise is appreciated. Time for me to lean something new.
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