How to solve speaker 'hum' due to powerline network

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Re: How to solve speaker 'hum' due to powerline network

Postposted on Mon Jun 11, 2012 2:00 am

Sorry, I didn't see your question. It's a bit late now for the clarification, but I plugged it into a different socket 5 feet away. I believe it's on a different circuit. Thanks again for all the info. The powersupply has worked a couple times, keeping my machine on uninterupted when the power has gone out due storm activity.

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Re: How to solve speaker 'hum' due to powerline network

Postposted on Fri May 31, 2013 2:11 am

Discovery of this discussion saved me a lot of time in resolving the same issue with noise in my computer speakers due to a powerline device. I have a Windows 7 machine and the same Cambridge speakers as Disco. I installed a Netgear Powerline 500 WiFi Access Point, model XWNB5201 and got sporadic soft crackling sounds coming from the computer speakers. When I unplugged the powerline device at the computer (VS what I'll call the remote powerline device) the sound stopped. When I shut the computer down the sound stopped. The computer is in my home office and the remote powerline device is in a family room in the opposite side of the house. In the office I have a DSL connection to the internet. The crackling sounds became more constant and frequent as my internet browsing activity increased. When streaming a Netflix movie the soft crackling was constant. It was irritating enough to make me search for a solution and I found this discussion. I moved the powerline device at the computer to every outlet in the office, the sound persisted. All outlets in the office are on the same circuit breaker. Finally I moved the powerline device to an outlet on another circuit and the sound was gone. I was lucky to have an outlet on a different circuit close to my office. Wanted to add my experience in hopes it may help others the way this discussion helped me.

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Re: How to solve speaker 'hum' due to powerline network

Postposted on Wed Dec 03, 2014 5:41 pm

Also having this issue, but I'm renting an apartment and don't have the option to move the powerline device to another circuit. I was actually planning on getting the same UPS as Disco, but it seems that it did not fully resolve the issue. My problem sounds much more like msmunger's where it's not a steady hum but instead audible noise that fluctuates based on network activity. I wonder if Disco and msmunger's issues are similar but distinct. I've considered getting a UPS with "Active PFC" as that seems more likely to ensure "clean" power is getting delivered to my speakers and computer.

Perhaps it's not that the speaker power is dirty, but instead the signal delivered along the ethernet cable from the powerline adapter to the computer then into the motherboard and into 3.5mm adapter to the amp and then from amp to the speakers. I'll try unplugging the powerline adapter's ethernet cable on the comp side when I get home and see if that helps . I don't really hear the noise on the headphones plugged into the computer, but only the speakers attached to the amp attached to the comp. The amp has a separate power cable attached to the same power strip as the comp.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Wed Dec 03, 2014 6:07 pm

I've always had some degree of noise with internal PC audio. Sometimes it's the power. Sometimes it's the receiver I have the system hooked up to. Sometimes the video card is so awesome it radiates its warm glowing warming glow right into the audio lines, and you can actually hear the noise changing when you move the mouse. The only real solution I've found is to use a digital audio connection to get the signal out of the computer box. If I plug the analog line out from my PC into my stereo I'll get noise. If I run HDMI audio to my TV (which I use as my primary display) and then run an analog line from the TV into the stereo I don't get noise.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Thu Dec 04, 2014 8:43 am

@Errant911 - If you can't hear the noise on headphones, the amp may be picking up EMI through the cabling between the PC and the amp. Looping the audio cable several times through a ferrite ring and/or using a better cable may help.

Or it could be that your PC's line out is just noisy. You could diagnose this by temporarily switching the amp connection to the headphone jack.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Thu Dec 04, 2014 2:42 pm

Both the speaker amp and the headphones are connected to the comp by standard 3.5mm aux jacks into the computer motherboard.The MOBO is a GIGABYTE GA-P55A-UD3 LGA Image
On the front, there is a bank of 6 different colored ports to plug the jack in all right next to each other.

The headphones and the amp are each connected to one of the jacks. I am going to turn the headphones up and see if the noise is there, just not as noticeable. If it is, then it's not likely to be the A/C power that's dirty, but instead some interference making its way into the mobo from the powerline. Btw, my amp is something like "Pyle Home PCA4 Mini 2x120 Watt Stereo Power Amplifier" (i'm not at home so I don't know the exact power rating, but it's that base model).
Image
Nothing fancy, and I've never had any issues with it until now. The noise is present whether or not any music/sound is being pushed through the speakers and is independent of the volume setting on the amp.

**Apologies for the large images. I tried to link to the product pages, but got a notification saying I can't post URLs.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Thu Dec 04, 2014 7:28 pm

Pyle, ugh. If anything had a corner cut in that setup, it'd be that.

If the sound comes though regardless of the volume level set on the amp then it's coming in through either your input cables or your power line on the amp itself.

EDIT: Another check - if you turn down the volume on your computer, does the sound become more quiet?


For a cheap replacement (that probably puts out just as much, if not more, power) you might consider: http://www.amazon.com/Lepai-LP-2020A-Tr ... p-2020a%2B
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Thu Dec 04, 2014 8:55 pm

Also, the amp is likely more sensitive to low-level interference than the headphones. If the problem is induced EMI in the cabling, the low(er) impedance of the headphones (compared to the amp's line in) could be skewing things.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Tue Dec 09, 2014 5:59 pm

@Waco Yes, the amp was purchased as a cheapo option to connect everything, and I simply never got around to replacing it.

Things I've checked that have NOT had any affect on the existence or volume of the noise
  • Unplugging ethernet cable between powerline device and computer
  • Adjusting volume on the computer from min to max
  • Adjusting physical volume knob on the crappy amp
  • Allowing everything to "warm up"

I really expected adjusting the volume knob on the amp to change the volume of the noise, but I've not heard any change. Also, regardless of the volume setting on the computer, I could not hear the noise on my headphones (Audio Technica ATH-A700X).

**Update 2014-12-12. Disabling the ethernet adapter on the only computer using the powerline device eliminates the interference. I can still browse via Wi-Fi with no interference even with the powerline system still connected. Only when I re-enable the comp's ethernet adapter and browse the net through the hardwired connection does the noise return.**
Last edited by Errant911 on Fri Dec 12, 2014 7:50 pm, edited 1 time in total.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Tue Dec 09, 2014 7:48 pm

Sounds like the crappy amp is... well... crap. Time for a new amp.
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Fri Dec 12, 2014 7:33 pm

I think I might get this filter http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=C2
Image.
Manual says it has between 40-50 dB of attenuation for EMI/RFI noise from 150kHz - 30 MHz which is the bulk of where powerline networks transmit (source http://www.itworld.com/article/2832302/how-and-why-to-extend-your-network-with-power-line-networking.html

Here is the model of powerline device I use. It claims a frequency band of 2MHz-68MHz. I should send them an email that their "built-in RFI/EMI filters" are crap... http://www.zyxel.com/us/en/products_services/pla5215.shtml?t=p
Image

Even with the filter, I may hunt for a new amp/receiver. Time to do some shopping, but I'd like to stay in $50-75 range.

I'll update the post if something I try resolves the issue. The other night I tried disabling the ethernet adapter on the computer (so no data would be requested through the powerline system), and the interference disappeared. So... even if the powerline is connected and operating, it only causes interference when I request data through the hardwired connection (but no noise when using purely Wi-Fi).
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Re: How to solve speaker 'hum' due to powerline network

Postposted on Fri Dec 12, 2014 9:40 pm

Errant911 wrote:The other night I tried disabling the ethernet adapter on the computer (so no data would be requested through the powerline system), and the interference disappeared. So... even if the powerline is connected and operating, it only causes interference when I request data through the hardwired connection (but no noise when using purely Wi-Fi).

That being the case, I'm thinking it is possible your amp is picking up radiated EMI from the Ethernet cable or NIC, not from the powerline network. Filtering the power line isn't going to make any difference if that's what is going on.

You're also going to have a tough time getting a quality amp for $50-$75, so if that's your budget I think it is going to be hit-or-miss whether it's an improvement over what you have now.

Edit: Wait... a few posts back you said disconnecting the Ethernet cable had no effect. But disabling the NIC made the noise go away? Please confirm. The PC would not have been receiving data over the powerline network in either case.
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