Static in headphones when plugged in to computer

[Wallybot]

So i have a bit of a problem here. I have a dell xps desktop that i use to listen to music and play games. I connect it to a fiio e07k to it as a dac/amp. I have ATH-M50s as headphones. The problem is whenever i plug everything in, there is buzzing and static. I have tried plugging the amp in before powering on the pc and what i have found was that if i plug it in while the pc is completely off, it still has static. However, when i pull the power plug, it goes away. Another interesting thing I have found was that if i have plugged everything in, turned on the computer, there would be static; but once i touch the metal back part of the pc, the buzzing and static gets significantly less. So, what is causing this noise and is there anyway for me to remove the static noise other than having my hand on the tower at all times?

 

[threephi]

Sounds like a grounding problem.  Are all your extension cords and power strips in good shape?

 

[Wallybot]

That was definitely the problem. Switched out the surge protector and static is completely gone. Thanks very much 

 
Now, I can finally listen to music on this computer without that annoying background noise.

 

[threephi]

Glad to hear you got it fixed!

 

[Wallybot]

Unfortunately the static came back 

 So, I tried unplugging all of the usb's to see if that's the problem. Turns out, the static gets even worse when only my amp is plugged in. I'm suspecting cause of the static is my computer. Any Ideas?

 

[threephi]

Hrm, there's definitely a grounding problem somewhere.  It's hard to say exactly where the issue is originating, but after reading over your posts again, the next thing I would look at are the cables you use to connect to the fiio.  There might be a split in one of the wires.  If you have doubles, try swapping those cables out.

I'm a little unclear on exactly what's going on though--did the problem stop when you switched out the surge protector, and then it came back?  Can you give some detail about how your electrical cables are set up?  Eg. is this in your home, what kind of building and how old, is everything plugged into a three-prong or two-prong socket and do all the electrical cables have three wires or two, is everything connected to your computer plugged into the same power strip?

The two ways to approach a ground problem in terms of audio buzz is either make sure everything is properly grounded into the same electrical source (in other words, not having different components coming out of different sockets), or go the complete opposite and make sure that everything is ungrounded.  Although I wouldn't recommend that for your computer since not having your computer grounded is unsafe.  Having everything properly grounded also means knowing that your electrical wiring inside the walls is hooked up correctly, and if we're talking about a old house, that's a common problem and is sometimes not so easy to fix.

 

[cdsa35000]

Is the PC power grounded? seems not otherwise it wont have effect when touching the metal case, in this case the static noise/leaking current is using your body as ground..
So try a grounded outlet.

Otherwise cut the shielding of the USB cable to amp, this act as 2nd groundline and probably can cause the groundloop/static noise.
see info:
http://www.head-fi.org/t/745220/help-humming-noise

 

[Wallybot]

Sorry for being unclear about my setup. This is all at my house and it was built around 10 years ago so its fairly new. This is the surge protector I had switched out and currently using:

 

http://www.radioshack.com/enercell-7-outlet-2100-joule-surge-protector/6100062.html#.VKYlJCvF98E

 

Initially, when i switched, the static seems to stop. The next day, it came back so the surge protectors don't seem to be the problem. Also, I have switched/checked cables so that is not the problem.

 

So I have checked everything to make sure everything is plugged into the same power strip. My outlet has two three-pronged sockets. One is occupied by a Powerline Adapter that i use to get wired internet to a laptop downstairs. The powerline has only 2 prongs. The other socket is being used by the surge protector that powers my monitors, pc tower, router, and modem. All the components connected to the surge protector have 3 prongs except for the modem/router.

 

This is what the connections look like:
 
http://goo.gl/Lwqn2L
 

 

At first glance, everything seems to be plugged into the same powerstrip But I disconnected the powerline to test the static and surprisingly all the static left.

 

After disconnecting the powerline for an hour or so, the static seems to still be nonexistent. So was this the cause of all the static? I didn't expect that the static would travel through that big of a distance.

 

 

 

 

 

[threephi]

  Sorry for being unclear about my setup. This is all at my house and it was built around 10 years ago so its fairly new. This is the surge protector I had switched out and currently using:

 

http://www.radioshack.com/enercell-7-outlet-2100-joule-surge-protector/6100062.html#.VKYlJCvF98E

 

Initially, when i switched, the static seems to stop. The next day, it came back so the surge protectors don't seem to be the problem. Also, I have switched/checked cables so that is not the problem.

 

So I have checked everything to make sure everything is plugged into the same power strip. My outlet has two three-pronged sockets. One is occupied by a Powerline Adapter that i use to get wired internet to a laptop downstairs. The powerline has only 2 prongs. The other socket is being used by the surge protector that powers my monitors, pc tower, router, and modem. All the components connected to the surge protector have 3 prongs except for the modem/router.

 

This is what the connections look like:
 
http://goo.gl/Lwqn2L
 

 

At first glance, everything seems to be plugged into the same powerstrip But I disconnected the powerline to test the static and surprisingly all the static left.

 

After disconnecting the powerline for an hour or so, the static seems to still be nonexistent. So was this the cause of all the static? I didn't expect that the static would travel through that big of a distance.

 

 

 

 

Wow, when I asked for details I didn't expect that incredible schematic!  I've never seen mindmup before either so thanks for turning me on to that, and thanks for that crystal-clear description of your setup.

Based on the above, it seems apparent now that the powerline ethernet data signal is to blame.  That perfectly explains the intermittent nature of the interference you were seeing, which I found a bit baffling.  Powerline ethernet works by piggybacking a data signal onto the standard 60Hz 120V sine wave that comprises household AC electricity (in the US; for sake of argument since that's where I am).  The added noise of the ethernet signal won't make a difference to toasters and desk lamps, but as one might expect, it does affect audio components.
 
The solution (assuming you stick with powerline ethernet) is to put a line filter or power conditioner on the socket supplying your power strip, so your components get a nice smooth sine wave for AC power.  Perhaps the manufacturer of your powerline ethernet devices offers something to serve that purpose.  Otherwise there are a lot of companies that make power strips or bricks with line filtering built in, which can range anywhere from $50 bucks or so to several hundred for a nice UPS (uninterruptible power supply).  Unfortunately I've never had cause to purchase one for myself so I can't make a recommendation, but a little googling should turn up a lot to choose from.  Like pretty much everything having to do with electronics, you get what you pay for so I would avoid the rock-bottom cheapo products.

 

[cdsa35000]

Try tto find out if the interference is coming from the ethernet cables (ground) from the modem to pc or when powerline adapter/ethernetcable is connected or not if its coming through the poweroutlets.
Try put powerline adapter and modem to the same side or switch etc. to to same outlet of the pc side etc.

http://www.google.com/search?q=powerline+adapter+static+noise

 

[Wallybot]

Thanks guys! Now that I know where the problem is, I'm probably going to get a not too expensive power strip with filtering or a UPS in place of my current surge protector in the future. Until then, I'll just unplug the powerline whenever I'm using my headphones and replug when I'm done. Kinda a hassle but will work. Thanks again for helping me find the problem and I learned a few things from this too.