Laptop power cable causing weird noise through speakers

[furrywolfinnc]

Hi, I have a strange problem. it's similar to some I've read about only I have a strange static/feed back/white noise type of noise which comes through my speakers when my laptop is connected to my stereo (from the headphone socket in the laptop to the phono sockets in the stereo) or tv (from headphone socket to jack input on tv), only when the laptop is plugged into the power.

I've had this set-up for sometime now though, and I can't figure out why it's suddenly causing this problem. I'm wondering if there's a problem with the actual power cable/charger thing for my Acer Aspire 5735. I've tried plugging it into different sockets and that makes no difference either. There are also no other cables near it... 🙁

Use the line out instead of the headphones and the tape in instead of the phono. Much of your issue has more to do with level and impedance matching. Turn up the output volume from the laptop to feed as much "clean" signal to the stereo as possible before turning up the stereo. There is a small level of noise from the laptop and the greater signal to noise ratio you can give the stereo the better. If you turn the level down on the laptop and then turn up the stereo the noise will be worse because the signal to noise ratio is worse.

Other issues might include cable quality and electrical grounding issues.

 

[jeffpgc]

It is a ground loop problem. The cheapest easiest way to correct the problem is to plug your laptop in using one of the adapters you use if your plugs in the house don't have a ground prong. This isolates the ground from your laptop. Worked GREAT for me!!!

 

[goldpanner]

I had a similar problem to LoonyLinee (noisy laptop when power cord plugged in). I am using USB "line" output from laptop to pro audio equipment ... After reading the posted solutions I thought some of you might be interested in a solution that worked for me.

Using a standard Toshiba computer and power supply (this should be irrelevant) -- I plugged the power supply into a simple three prong input and two prong output "cheater" AC adapter -- and then plugged the "two" prong side into my wall socket (therefore removing ground connection).

This simple adapter can be purchased from eBay for a couple of bucks (if you don't have one handy already). -- Or you might find one at your local hardware store 🙂

 

[toldyouso]

I have found it very amusing reading about ground loop noise on the web - people blaming capacitors, power supplies, mobile phones, mismatched impedance, people suggesting low pass filters, adapters and ground loop isolators, yadda yadda, sometimes I do wonder how people can be so daft. This is not ASIC design we're talking about here, this is a ground loop. This is really not difficult. It's a ground loop. Think about the problem for a second. Stop panicking, stop trying to fight fire with fire, stop what you're doing and just think about the problem for a moment. The solution is staring you in the face. If you can't work out what it is then shame on you, you are an idiot.

 

[imanidiot]

I'm an idiot. I get the same problem with white noise and humming, but only when the AC adapter is connected. I get it out the 3.5 mm audio plug as well as through the USB and an external sound card. toldyouso, what ground loop solution do you recommend.

 

[sectio]

I have found it very amusing reading about ground loop noise on the web - people blaming capacitors, power supplies, mobile phones, mismatched impedance, people suggesting low pass filters, adapters and ground loop isolators, yadda yadda, sometimes I do wonder how people can be so daft. This is not ASIC design we're talking about here, this is a ground loop. This is really not difficult. It's a ground loop. Think about the problem for a second. Stop panicking, stop trying to fight fire with fire, stop what you're doing and just think about the problem for a moment. The solution is staring you in the face. If you can't work out what it is then shame on you, you are an idiot.

Your comment was absolutely worthless actually.. idk what you wanted to prove.. not even you didn't help but you also used other people's time in reading your arrogant and worthless post.. sad..

Back to the topic.. I have the same issue (bzz noises when AC is connected to laptop). One other thing i noticed is that the sound goes away when i touch other connections with my finger (e.g. HDMI socket, USB 3,0 etc..) so i guess it is indeed a grounding issue.. But this only happen with the headphone i brought yesterday, it didn't happen with my previous headphones. So only way to fix this is buying the isolator? I think i'd better buy different headphones then and use there with my phone instead...
So? Any other solution?

 

[scottjamo]

Hi all. Looks like this issue has been covered quite a lot so sorry to revive.... Ive ordered a couple of ground loop isolators to try but I think the issue I have is slightly different. I find if I move the laptop power supply cables block, the noise goes away for a while, but sure enough it returns a few tunes later. Thanks in advance for help

 

[tonymul]

im also having this issue and the only way i solve it is by disconnecting the ground wire