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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
890 posts
 
Rodman - At your suggestion, I've been reading about the TI shield. It looks like a very interesting product. I think I will order some. Thanks.

Bryon
rodman99999
6,159 posts
 
A simple(but efficacious)solution. Happy listening!
kijanki's avatar
kijanki
4,428 posts
 
Bryoncunningham, Jitter creates sidebands to root frequency (like any modulation) at very low levels. In spite of low levels it is very audible because it is not harmonically related to root frequency. With music (many frequencies) it is basically a hash with amplitude proportional to sound level. When music stops noise stops as well. It can be detected only as a lack of clarity.
bryoncunningham OP
890 posts
 
My TI Shield arrived yesterday. I was thinking about placing it around the switching mode power supply in the G68. I think Kijanki warned me not to get magnetic materials too close to the power supply.

Anyone know how close is too close? And what would happen?

Thanks,
Bryon
bryoncunningham OP
890 posts
 
Update… Things are winding down. Here’s what I’ve added to the system:

--A total of 11 shields to the Meridian G68. Each shield is a sandwich comprised of 16 gauge copper, 22 gauge steel, and TI Shield. I placed shields around the power supply, the analog output stage, the clock, and the lid. All shields are grounded to the chassis. You can see a picture of some of the shields here.

--Aluminum enclosures around the Empirical Audio reclocker and the Sonos. I reinforced both enclosures with 16 gauge copper and 22 gauge steel.

--A sheet of ERS Cloth inside the G68, and 2 sheets inside the door of the breaker panel.

--A 22 gauge steel plate under the Pass amp.

--A 22 gauge steel plate on top of the Hydra power conditioner.

--2 shielded Cat6 cables to replace the unshielded Cat5 cables.

--A shielded Netgear ethernet switch to replace the Apple Airport.

--VH Audio’s 10 gauge cryo’d romex for my dedicated line to replace standard 12 gauge romex. I rerouted the line to minimize the distance to the breaker and to avoid crossing any other lines.

The only other thing I have yet to do is install a new outlet. I've ordered a Maestro outlet to replace my Synergistic Research Teslaplex, which I've just discovered has a magnetic backstrap.

The results of all these changes are excellent. Greater resolution, better harmonic accuracy, better bass definition, and more precise imaging. Overall, things sound more natural and less “hifi.” I am pleased.

Thanks to everyone for your help.

Bryon
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