Headphones and static discharge

[Will Rickards]

So I got a new PC at work. SSD, new dock, new ac adaptor.
I have a radioshack headphone extension cable that runs across the desk. Then I plug my headphones (cheap philips pair of in-ear SHE2642). The head phone extension plugs into the dock. Computer is Dell Lattitude E6420.

Works fine, except when I move my chair. I get feedback in the headphones. This didn't happen before. I can't always make it happen either. I'm guessing it is some static discharge or something.

Also of note is the AC adaptor makes audible noise. But I checked somebody else's one and it makes the same noise. Sounds like faint hard drive noises.

How can I avoid this feedback? Maybe I'll try plugging into the laptop and not the dock for a while and see if I get the feedback. However when plugging into the laptop the volume level is much higher.

 

[ddrueding]

Any way to check the ground on your computer?

 

[Handruin]

Maybe adding a ferrite core might help? If you have any floating around at home, try putting one on each end of the cable to see if it absorbs any of the EMI. It may not help, but just offering an idea.

 

[Howell]

Is it possible the cord or input jack is damaged? It could be that the way it cord was positioned before did not allow the chair movement to flex the cable. Do you get the same results if you are just standing and moving as opposed to rolling?

 

[Will Rickards]

Chair doesn't have to move for it to happen. Body movement can trigger it. But I can't make it happen on demand.

The headphone extension cord is pretty heavy duty so I don't think it was damaged.
The philips headphone cords are wimpy and I guess they could be damaged. But I have the extension so I'm not pulling on them and also because the jack is too far away.
Maybe I should try other headphones.

I have no idea how to check the ground. I don't think I have a voltmeter.

 

[MaxBurn]

Several podcasts I listen to have had mentions of static in their earphones shocking them in the ear during the show. It's made for some interesting listening with sudden cursing tourettes style.

Wear an anti static wrist strap?
Go with a wireless headphone setup?
Ground your chair and thus yourself somehow?

 

[ddrueding]

If the electricity is going into your head, I don't think that encouraging it to pass through your body by grounding you/your chair is the right direction to go.

 

[MaxBurn]

Interesting point but electricity should not be going into his head. If so it isn't a static problem. Is there even exposed metal on the headphones?

 

[ddrueding]

I was just going back to the podcast/shocking reference above. There should be no electricity to the head, and there is likely not any uninsulated metal in the headphones.

 

[Stereodude]

Get an ESD ground strap.

 

[MaxBurn]

BTW, ESD straps done correctly have a huge resistor inline so that you can't ground and kill yourself by hitting voltage somewhere.

 

[Will Rickards]

I bought these headphones. They don't seem to exhibit the issue so far. It has only been a few days though.

They are definitely different as they go more into the ear. More bass too.