Interference on sound and monitor when I plug my laptop in to charge.

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Discussion Overview

The discussion revolves around the issue of electromagnetic interference (EMI) experienced when a laptop is plugged in to charge, affecting both the monitor and audio output. Participants explore potential causes and remedies related to the setup of cables and power supplies.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests that the interference is likely due to the higher voltage power wire causing EMI, recommending that the power supply wire be kept separate from audio and monitor cables.
  • Another participant proposes using a ferrite toroid to reduce interference in the audio cable, emphasizing the importance of cable separation.
  • A participant questions whether modifications can be made to the power supply to mitigate EMI, specifically noting the interference with the monitor.
  • One participant shares an anecdote about similar interference issues encountered in car audio systems, suggesting that routing power and audio wires too closely can lead to audible hums.
  • Another participant mentions the possibility of using EMI shielding tape on the monitor cable as a potential solution.
  • A participant indicates that their laptop model is a Gateway M-6750 and expresses uncertainty about the effectiveness of moving the power adapter away from the monitor.
  • There is a mention of the laptop using a Switch Mode Power Supply, with speculation that it might be allowing some AC interference to pass through.

Areas of Agreement / Disagreement

Participants present multiple competing views on the causes of the interference and potential solutions, with no consensus reached on the most effective remedy or the exact nature of the problem.

Contextual Notes

Participants express uncertainty regarding the effectiveness of various proposed solutions and the specific characteristics of the power supply and its impact on EMI. There are unresolved questions about the nature of the interference and its relationship to the laptop's design.

Qaiphyx
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I use my laptop as desktop, run a monitor on it and speakers etc... anyways when I plug it in it causes interference in the monitor and sound. Anyone know what causes this?? And how to remedy the problem.
 
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The interference is probably coming from the higher voltage power wire... EMI. Make sure that the wire for the power supply doesn't run parallel with either the audio or monitor cable and try to separate them as much as possible. For the audio cable you can purchase a ferrite toroid to get rid of some of the interference in case you have trouble keeping them separated.

http://www.mag-inc.com/ferrites/ferrite_toroids.asp

You'll loop the speaker wire around the toroid like so... more loops for greater interference...

http://www.arrl.org/news/features/2001/09/14/2/toroids-2-lrg.jpg

The best place to get them is from old junk PC power supplies... can't beat them for free! That's where I've gotten mine at least.
 
Last edited by a moderator:
B. Elliott said:
The interference is probably coming from the higher voltage power wire... EMI. Make sure that the wire for the power supply doesn't run parallel with either the audio or monitor cable and try to separate them as much as possible. For the audio cable you can purchase a ferrite toroid to get rid of some of the interference in case you have trouble keeping them separated.

http://www.mag-inc.com/ferrites/ferrite_toroids.asp

You'll loop the speaker wire around the toroid like so... more loops for greater interference...

http://www.arrl.org/news/features/2001/09/14/2/toroids-2-lrg.jpg

The best place to get them is from old junk PC power supplies... can't beat them for free! That's where I've gotten mine at least.


Hmm, are there any modifications that I can make to the power supply EMI? Its mostly the interference it causes in my monitor that bothers me.

Wasnt the interference problem a factor when they decided to use this type of power system?
 
Last edited by a moderator:
Qaiphyx said:
Hmm, are there any modifications that I can make to the power supply EMI? Its mostly the interference it causes in my monitor that bothers me.

Wasnt the interference problem a factor when they decided to use this type of power system?

EMI stands for electromagnetic interference. The most typical problem I've run into like that is when people install an amp in a car and they make the mistake of running the power wire along the same side as the audio signal wire. When they're routed that close together like that, they end up making the rear speaker emit an audible hum that increases in frequency with the engine RPMs... pretty annoying.

An option for the monitor cable would be to get a roll of EMI shielding tape and wrap the monitor cable with it. It sounds like the monitor output is very close to the power plug which is unusual... for the reasons your experiencing.

What model is your laptop?
 
B. Elliott said:
EMI stands for electromagnetic interference. The most typical problem I've run into like that is when people install an amp in a car and they make the mistake of running the power wire along the same side as the audio signal wire. When they're routed that close together like that, they end up making the rear speaker emit an audible hum that increases in frequency with the engine RPMs... pretty annoying.

An option for the monitor cable would be to get a roll of EMI shielding tape and wrap the monitor cable with it. It sounds like the monitor output is very close to the power plug which is unusual... for the reasons your experiencing.

What model is your laptop?

Its a gateway M-6750. The wire was a little but its not now and still giving the same problem. I was reading that I have a Switch Mode Power Supply, and that it might be letting some ac slip by or something? Yah I read about the EMI too i was thinking about maybe getting and EMI filter. But honestly haha I have no idea what it is. I moved my power adapter as far away from the monitor as i could but that didnt fix the problem.
 

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