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Comment by Gracana | Hacker News Reader

If you're a bit handy, you can assemble a line filter using a part like this https://enerdoor.com/products/fin27/ for a heck of a lot cheaper than you can buy a filtered power strip.

You may also be able to solve the problem with a simple common mode choke, either the clip-on type, or a toroid that you wrap the cable through a couple-few times. https://palomar-engineers.com/rfi-kits/acdc-power-line-choke...

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A filter like that will have very little attenuation in the audio spectrum.

I agree however that indiscriminately throwing ferrites at problems can be a good solution!

Maybe you’re right. My experience is with radios, where it’s possible that high frequency noise is conducted into the RF section rather than into the audio amplifier. I know that in one case, both my transmitted signal and received audio output were absolute garbage (edit: because it was picking up noise from the vehicle ignition) until I added a choke to the power input wiring.

This reminds me of my favorite "Downfall" meme video.

[Youtube] "Hitler fails radiated emissions" - Orin Laney: https://www.youtube.com/watch?v=eeo8ZZTfwZQ

Even if there's very little audio-frequency attenuation, it's possible for higher frequencies to produce audio-frequency intermodulation distortion, and filtering could reduce this. This is one reason "high definition" (ultrasound sampling rate) audio is a bad idea as a listening format.

Ferrites - almost never doing any harm, sometimes doing good. :-)

In 2013 I bought out 2 Radio Shacks worth of ferrite beads when I was hunting down signal noise in my senior design project (CNC mill rebuild and update.) All else fails, add more beads.

Also, I learned that you can make your own shielded flat cables with aluminum duct tape.

Who knew that they had a really good reason for using 48V signaling in the original machine controls from 1986?

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