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Shielding components from EMI/RFI... Help please

A recent experiment with a product designed to reduce EMI/RFI left me curious about other ways to reduce EMI/RFI in my system. In the past ten days, I've stepped onto a slippery slope, at the bottom of which is surely some kind of insanity...

I've been experimenting with copper plates in an effort to absorb, deflect, diffract, and block EMI/RFI. I've tried copper plates under components, on top of components, and inside components.

This is the point where you tell me I don't know what I'm doing and I'm likely to short circuit something and/or electrocute myself. Consider me duly warned. This is also the point where you tell me to get some balanced interconnects, or at least to get some shielded interconnects for Chrissake. Consider me duly informed. Moving on...

I'm hoping you can help me make the most of this experiment, and help me avoid killing a component or myself. My strategy so far has been to:

1. Place copper plates at locations that generate a lot of EMI/RFI, e.g., components with switching mode power supplies or high frequency clocks. The system has a total of 3 SMPS and 3 clocks.

2. Place copper plates at locations that are vulnerable to EMI/RFI, e.g., under the amp, near the transformer.

3. Place copper plates inside noisy components -- in particular, my Meridian G68 preamp/processor. I've begun to build 2 partial Faraday cages, one for the SMPS, and one for the analog output stage.

4. Ground the copper plates either to the component chassis (when plates are used inside a component) or to an independent ground point (when plates are used above/below a component).

Has anyone tried this sort of thing?

Bryon
bryoncunningham
bryoncunningham OP
903 posts
 
Thanks, Al, for your explanation of the signal ground binding post on the amp.

Your hypothesis about the ERS is interesting. I plan on removing it from the G68 temporarily to see if things get better or worse, now that I've made so many other changes to the G68 and the rest of the system. I will report back the result. I might post my findings in the Magic thread, since (I now recall) that's where most of the discussion of ERS occurred.

RFI pigtails can IMO be placed somewhere close to the border separating the remotely plausible from the totally preposterous.

That made me laugh. And I'm not surprised to hear you say it. I suspected as much. It's strange the things you will do when in the grip of addiction. :-)

I looked at the thread you linked. An interesting discussion of another Magical device, if you can call a piece of wire a 'device.' All your skeptical comments make perfect sense. Still, after reading that thread, I want to try it.

One day at a time. One day at a time.

Bryon
sabai
2,027 posts
 
Bryon,
You might want to read my new thread on Synergistic Research Mini Power Couplers. It is related to EMF protection.
almarg's avatar
almarg
9,670 posts
 
Bryon, an additional point occurs to me regarding the ERS cloth. Since its core is somewhat conductive, if it is placed close to circuitry (significantly closer than the metallic structural surfaces of the component), its presence could affect the amount of stray capacitance between arbitrary circuit points. It could therefore conceivably have effects via mechanisms that are unrelated to RFI.

How close is "close" is unpredictable, and would be dependent on the particular circuits and circuit points that are involved. The effects that would result, if any, would also be unpredictable. In general, I would guess that the circuit points that would be most sensitive to those effects would be certain kinds of analog circuit points, such as what are known as summing junctions, and other points that are within feedback loops.

Best,
-- Al
lewinskih01
912 posts
 
Bryon,

Been following and learning from this thread. Thanks for keeping it going!

I'm getting the itch to try some of these. The ferrites seem like the easiest place to start. I understand ferrites need to be carefully chosen by frequency. Which ferrites did you choose and why, and which were the most effective places for them?

Cheers!
sabai
2,027 posts
 
Bryon,
I am an inveterate tweaker. Neodymium magnets are among my favorite tweaks. I place them on or under components near transformers to draw off EMFs. The effect can be to increase the focus of instruments and voices and to provide a clearer sound than without the magnets in place.

Yesterday I got a big surprise. I went around my system with a bundle of 4 neodymium magnets to see if I could feel any strong magnetic fields coming off of components or cables. I arrived at a Synergistic Research MPC. Lo and behold I felt a very strong magnetic field when the magnets came close to the MPC. I guess this should have been no surprise but I had just never got around to doing this kind of system test before. There was a spot on the back of the MPC where the magnets wanted to be. So I went through my system and let the magnets find their place on the back of 5 MPCs in my system -- mostly Galileo.

I flipped my system breaker and when the first sounds came through my speakers I knew the magnets were making a real difference in the sound. Instruments and voices became more focussed as well as smoother. The soundstage became a tad more recessed but also somewhat deeper. The sound is now softer, more pleasing and more musical to my ears -- without any loss of resolution. I am using all of my reference CDs to test this today and the results are uniformly good.
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