Laptop power cable causing weird noise through speakers

I am going to guess that you have a cell phone somewhere near the system. Incoming calls/text messages will often crerate interference that poorly shielded devices, like speaker wires will pick up. The easiest solution is to move the phone farther away from your computer.

It is also possible to pick up other devices causing interference as well (referred to as RFI - radion frequency interference). Moving them away from the immediate proximity of your computer should clear up the noise (like a home wireless phone, pager, Blackberry, etc.).

Good luck!

well since the audio chip in a laptop is crammed in there with all the other stuff, it could be electrical interference with something else in the laptop (maybe the power circuitry). or the cable your using to hook it up to the stereo is cheap unshielded junk...

Thanks for your reply, I know that things like that can cause interference but as I said this only happens when the laptop is connected to a power supply. The laptop can be on and connected to the stereo or tv while not connected to the power supply and no interference type noise is heard. However, it is only while it's connected to the power supply that this problem occurs. Hopefully a solution will be found anyway!!! It's slightly annoying when you're trying to listen to tunes and in the quieter bits you can hear it. I still do though... :0)

Yeah, that's possible. I suppose something could just have gone wrong... As I say it's a new problem. It's insured anyway! If I don't come up with something I'll have to get it looked at. Thanks for your reply.

One of the first things I did was try a different cable as I have several, not cheap either, but the problem persists, and once again I'll mention that it is ONLY when the laptop is not running off the battery, therefore the cable should make no difference...

It could also be poor grounding in your electrical system since it only occurs when attached to your power supply. Try this, use an extension cord to connect your power supply to a different outlet, preferrably in another room (different circuit) to see if that helps. Not practical, but may isolate the problem.

Thanks, you could well be right. I'm not sure we have more than one socket circuit as this is a fairly small flat but I'll look into that right now. I know that we have other dodgy electrical problems though (like lights flashing while off!), so it sounds like that could be possible although I don't know much at all about electrical systems. I'm sure our electrics are sub-standard though, and are probably well in need of an inspection. Thanks for that, sounds promising...  

I'm extremely confused now, but in a good way... I've just turned my stereo on to listen to music (obviously!) and the noise has gone! I've no idea why because I haven't been able to try any other sockets but hey! touch wood it'll stay this way!      

i know the post is old so i'm going to post just in case somebody else like me has the same problem. well it is poor grounding so i just plugged my laptop adapter to a orange construction extension i'm guessing it has better grounding then the regular one (not sure but its the only one i had) and plug it into a different outlet and you should be fine i only use it to listen to music or watch a movie thou hope it helps.

It's all down to bad grounding - a ground loop. Most computers get this and the easiest thing to do is to buy a Ground Loop Isolator and plug the laptop/PC in through that to a HiFi and that will get rid of all the nasty interference noise.  

I have much the same problem with a twist. The noise is about four notes, it repeats at a regular interval and is discernible EVEN IF THE SPEAKERS ARE DISCONNECTED FROM POWER AND DATA. Something in the air is causing a regular signal. It is like an alarm that can't get shut off.

Windows reports no applications running and I've rebooted with no effect.

I have another set of the same speakers and they don't chirp. I swapped power cords, the chirp stays with the speakers.

Scrapping the speakers seem the only solution, but I'd like to know what is causing it in case it happens again.

If its the speakers making the noise then you've got a faulty component in the speaker amp somewhere.

hey people this is Waheed 4rm Afghanistan and i have same problem from today morning ( 2.26.2012 ) I am confused that what should I do now?

Just when i am plugging power it makes some high noise through loudspeaker.

Hi all. Just to clarify, while many people DO have ground loop problems, it is also possible that this is a different issue. I've had the same problem with using laptops in studio setups - when the power adaptor is connected, you can hear a strange HF buzzing, performing actions such as moving mouse or trackpad causes a change in the sound too. My electrical engineer friend put this down to the way that cheap laptop power supplies work (by cheap, all laptop power supplies are mass produced as cheap as possible). Apparently, they regulate voltage by switching on and off very quickly. I eventually only solved this on my own setup by using an isolated sound card (Rane TTM57 - very expensive!) but my friend who has had the same problem this morning I have pointed him in the direction of this:

http://electronics-shop.dk/usb-isolator

I have NO idea if it will isolate in the same way, I'll re-post when I find out.

I had the same problem when connecting my laptop (via headphone jack) to my Denon home theater 11.2 system. The laptop cord was plugged in to one power strip and the Denon a different one, so its not this loop thing they are talking about. I was trying to use my laptop and XMradio, online access to play music thru my Denon system. I had the same whining noise coming through my "Definitive" speakers (good speakers!) - so it's not the speakers. I went searching online for an answer that would not cost me a thing. I discovered, on my own, that if i turn up the volume on the laptop (and even on the XM radio website's) AND turn down the Denon - guess what ? ? THE WHINING NOISE WAS DRASTICLLY REDUCED! I think the Denon was trying to overcompensate for the low volume on the laptop, when it was turned up....almost like turning up the speakers too loud that the speakers can't take the power, therefore they distort. Ok, back to listening to Jimmy Buffet in concert tonight....

Girl Power  

guyz please help i 'have ;a problem if i switch on my acer laptop it no 'coming it just give me a big noise that you can`t listen and ,it 'end up not coming anything in mthe screen please help guyz my email is dumisanimduduzi@gmail.com

Hi, I am having the same issue of when I plug in my Acer Aspire laptop to the power supply of different ac outlets, different houses, different audio jack cables and different stereo system, I always get this nasty interference and it is only when the ac power supply is plugged in. I have noticed that when I use headphones it does not create this problem, meaning that it can be plugged in to the ac adapter and I don't get interference with the headphones plugged in. LoonyLinee since you seem to have the exact same issue as I do and we have similar laptops, if you got a solution by now please let me know !

Hi, I am having the same issue of when I plug in my Acer Aspire laptop to the power supply of different ac outlets, different houses, different audio jack cables and different stereo system, I always get this nasty interference and it is only when the ac power supply is plugged in. I have noticed that when I use headphones it does not create this problem, meaning that it can be plugged in to the ac adapter and I don't get interference with the headphones plugged in. LoonyLinee since you seem to have the exact same issue as I do and we have similar laptops, if you got a solution by now please let me know !

this might help answer this question. I'll give information about my understanding on the subject so you can determine if this is what is happening. AC adapters create a wave signal that can create "noise" on analog devices. particularly speakers, which are always analog. Sorry, but there's no way around it. You may find that it doesn't manifest if your system is using an optical audio out cable.

Smaller speakers (unamplified devices) generally are able to hide this or have it less than noticeable. laptop speakers, headsets, earbuds, micro speakers, etc. If you add a power amplified unit in the mix, it may be noticeably more prominent in static. Loop or ground loop isolation with a transformer often can clear up this problem, as it filters out the cycling of AC on a line.

Ground loop isolators are pretty cheap and easy to find. just get a decent stereo one and test it out. Now it may be something completely different in some cases, but for a potential cheap $10-$20 fix, it is definitely worth checking out.

Thanks a lot ! I will try that ! By the way there are two types of ground loop isolators, the one that will be used between the laptop power supply cable and the ac outlet and the one between the 3.5mm stereo jack of the laptop and the mixer/amplified speaker. Which one should I get ? Thanks

This one:
http://www.amazon.com/Ebtech-Hum-Voltage-Filter/dp/B000...

Or this kind:
http://www.amazon.com/PAC-Ground-Isolator-3-5-Applicati...

it could be on the power supply itself. Bad capacitors inside could result in bad filtering of rf signals and most of the power supply design is SMPS meaning it generates high freq in the audio range and if not filtere well will somehow creeps and outs in audio circuitry in laptop. try change power supply. try to plug the speaker if it has amplifier inside to other source of audio (ex. ipod etc.) and see if it is normal.

Even if the AC adapter has a filter problem with the voltage, a ground loop isolator is still going to have significant help. While both will help, Generally you want an inline isolator directly on your audio line. The one that plugs into the wall just cuts the loop at a different area. You'd generally want that style if you get a hum on your amplified speakers and you haven't plugged anything into the receiver or amplifier. In the image, you can see the one I suggested is the audio line between your computer and amp/receiver.

Always try the inexpensive solution first (inline). If you still have an issue, you can then get the more expensive power line filter.