I have a crappy stereo system driving my monitors (it's a bit hacky I know, but I didn't have to spend money buying it). It has a nasty habit of picking up cell phone interference: that annoying sound that's cross between morse code and a dialup connection. My cell phone is on my desk, and I've situated it in a way that minimizes the amplitude of interference. (The frequency only occurs when connected to the Edge network, interestingly, 3G signal goes by unnoticed.)

What's the most efficient way to shield my stereo amp from my cell phone? None of my other components pick this up--would I have to mess with electronics inside the amplifier, or is it possible to construct some sort of faraday cage, either around the amp or around the phone? Knowing that a full cage around the phone would block reception, is it possible to simply put some sort of material in the line of sight between the phone and amp to solve the problem without losing reception?

The problem component is an RCA RS2042 Stereo. (Compact, consumer grade, 5-CD changer, 90 or so watts.) Its aux input is connected (with unbalanced RCA) to a Mackie 402-VLZ3. I've done enough troubleshooting so far to know that it's not even this 6-feet of unbalanced cable that's picking up the interference. It doesn't show up anywhere else in the system, and it is even picked up by the stereo when nothing else is plugged into it. The tiny gauge speaker wire isn't even the problem--there's a headphone jack on the amp/receiver. To be clear: the amp/receiver alone with no input and no speakers picks up interference that can be heard through headphones. These headphones pick up no interferences when being driven by the mixer.

  • Please describe your full system in a little more detail. Jul 3, 2011 at 21:40
  • @leftaroundabout Done. Let me know if you need any other specifics.
    – NReilingh
    Jul 3, 2011 at 23:56

1 Answer 1


It's a lot easier and cheaper to remove the problem (your cell phone) from the situation, than it is to shield all your components.

Depending on how your desk, wiring, and amplifier are arranged, you may be able to get away with one of the imperfect ideas and solutions mentioned at http://blogs.middlebury.edu/petar/2011/04/08/shielding-audio-equipment-from-cell-phone-interference/ and putting your cell phone on an anti-static bag on your desk.

  • Problem is it's an iPhone and syncs to my workstation. But the anti-static bag was EXACTLY what I was looking for! Thanks!
    – NReilingh
    Jul 6, 2011 at 1:47
  • Put your iPhone in airplane mode. Feb 14, 2014 at 7:47

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