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This questions is more related to computer + external electromagnetic interference with my PC.

I'm using a PC where one USB 3.2 Gen2 port is occupied with a USB 3.0 USB hub. I'm facing problem with specifically the USB sound-card connected to the USB hub.

At first everything is working and running good, but when I turn on the fan (a ceiling fan), or turn off - on the UPS or any other gadgets, it unplugs the whole Creative Sound Blaster Play! 3 sound card from USB. This is a problem in between meetings and such it becomes a problem because UPS has mechanical relay that turns off and on itself a lot of the times a day.

In other words, turning off and on some loads disconnects the speaker from the whole system. As far as I know, we don't have any ground issues. The speakers on the other hand, has no ground connection at all - nor the PC (Intel NUC) has.

I had this situation with a keyboard + mouse connected to a tablet in the same room, where the table wasn't connected to charger. Turning on any load used to disconnect everything immediately.

I don't see much solution online, but I have an idea to use a ferrite bead which can clip to the wire. But I don't know if the noise coming from the switches or relays is high frequency or low frequency.

Before buying and trying ferrite beads clip (choke), is it possible to deal with such electromagnetic interference with ferrite beads on both the ends of the wire close to the ports?

EDIT

Failing to reproduce

I initially started with a capacitor, charging and discharging it to generate sparks. It wasn't enough to reproduce the problem.

I took a 200 watt light bulb and connected and disconnected from wall which caused sparks, but it wasn't enough.

Another way to reproduce

Because I thought the cable in the sound system working as an antenna, I tried with an extension cord.

I have an extension cord with 5 meters wire: Extension cord with Indian plug

It has one neon bulb indicator connected to 100K resistor in series that shouldn't consume more than 3 watts of power when connected to 220VAC/50Hz. When I turn the extension plug on and off, the same thing happens.

Now this problem probably happens with the fan because it's far away from the switchboard and there's wire through the wall which is acting as an antenna?

15 Volts
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    Unlikely but if you have clamp on ferrites to try, go for it. The problem you describe sounds cable coupled (not sure that’s the correct English term) and therefore lower in frequency than where most clamp on ferrites are effective. If the cable is flexible enough, consider wrapping it around a toroid core to make a CM filter. It may also be as simple as a grounding issue. Can you draw a block diagram of your setup? – winny Sep 20 '22 at 21:53
  • What is this fan? Please edit your question and show us a link or a photo if possible, thanks. – rdtsc Sep 20 '22 at 22:03
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    If I read this correctly, you are changing the power draw (turning the fan on) and it causes a blip in the sound system, like it is turning off and on again? If so, then the problem is not EMI per se, but a power system that isn't responding well to transients, and maybe a big capacitor right next to the fan switch would be better. – Smith Sep 20 '22 at 22:14
  • It's not causing by fans, pretty much any load causing this problem - like switching the UPS which has minimal load connected, nothing to do with the ceiling fan. Also, if the speaker turns off, the PC will not unmount the speaker. The effect here is just physically unplugging the sound-card. This shouldn't happen unless there's a glitch in the power-supply of the Intel NUC itself, but that should also freeze the system or at least make the system misbehave if happens really quickly. – 15 Volts Sep 20 '22 at 22:31
  • In other words, simply unplugging the speaker doesn't disconnect itself from the sound card. I tried that bunch of times. Disconnecting the sound-card will unplug it from the PC (hence shows dummy output on Linux). So I highly doubt it's causing by sparks when you turn on the ceiling fan or relay. – 15 Volts Sep 20 '22 at 22:34

1 Answers1

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The solution to this was ferrite beads because it was caused by the current induced from the ceiling fan or long wire in the extension cable or other external sources.

To suppress this Electromagnetic Interference, I purchased one ferrite bead clip and put that on the USB wire of the sound-card, I don't see the problem anymore after many tries to reproduce this.

  1. The way I used the choke is like following: Ferrite bead on sound-card

  2. The other way to loop this around (if it's lose) is this: Ferrite bead with looped wire

Here the wire goes like a loop.

I also think properly shielded and grounded cables will work, but I'm not sure if the sound-card is using that. Also, I noticed no problems so far with this approach, even my keyboard and headphone has a bead!

15 Volts
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