[Gordy]

Hi All, I've been using self adhesive lead tape as a general all around chassis damper to great effect and am wondering if it makes an effective rfi/emi blocker as well?  Also, do faraday cages need to be grounded?  ERS seems to work, in its applications, as a stand alone.  Thanks!

[randytsuch]

Hi Gordy,
Since the lead tape is metal, it will block EMI.  What I don't know is if certain metals do a better job of blocking EMI than others.  For the levels of EMI we are dealing with, it should not really be an issue though, I would think any metal would work.

I have worked on EMI problems at work, and I have seem people use aluminum foil to block EMI, and it's quite effective.  Of course, it won't dampen like lead tape will.  But, it you just want EMI shielding, aluminum foil is more cost effective.

As for grounding, I thought an EMI shield needed to be grounded to work.  I am not sure how the ERS stuff works without getting grounded.  Oh, and for higher frequencies, the ground path needs to be low impedance.  This means a long piece of wire is a worthless ground at high freqencies (in the MHZ).

Randy

[Gordy]

Thank you very much Randy!  The cost isn't an issue really as I already have #'s of the lead left over from damping some bedroom sources.  I'm going to use it to damp out a coupla iso transformers and hoped it would do some shielding as well, as you've confirmed!  

My second concern, with a more or less true faraday cage, is that I'm seriously thinking of replacing most of a drop dead ugly amp chassis/cabinet with my own. It'll be oak so I'll be lining it with 100 mesh  copper (free). I'm now presuming that each "wall" will need to be soldered/mated and my ground wire is only going to need to be about 15" to reach the pre's ext. ground nut.   Sound about right?   I can use larger mesh or 1/16th plate if need be....  Thanks again, Gordy