Ground loop issue on my sound card
So I have this theory about Ground Loops.  It goes like this:  If someone blames a ground loop then it most certainly is NOT a ground loop.  So far my theory has been correct, and this case is no different.

What you are experiencing is a simple electro-static discharge, or ESD.  Just basic static electricity.  You move around in your chair, or rub your feet on the floor and build up a static charge on your body.  Eventually that charge gets big enough to jump across the air gap between your headphones and your ear.  

There are several ways to fix it.  Here are some ideas:


Change your shoes and/or clothes.  Different materials are more or less capable to generate ESD.  I can't tell you which materials are better or worse, since it depends on what your chair is made from and other random things.  Just try different things and see what happens.
Remove your shoes.  Rubber soles are generally worse than socks or bare feet.
When you do laundry, use a fabric softener that reduces static.  I use Bounce brand dryer sheets, but there are many others.  
Use different headphones that provide better insulation.  Maybe wireless bluetooth headphones.
Use an anti-static spray on your floor and chair.  There are commercial versions that tend to be expensive, or you can use a mixture of UNSCENTED liquid fabric softener and water and sprayed out of a simple spray bottle.  Do not make the mistake of using scented fabric softener!  Mix so that there is 25 to 50% softener to water.
Get a humidifier.  


I should also mention that ESD is bad.  Even though most headphone jacks are protected from ESD, if it happens enough then it could still damage your computer.  It is worth it to take the time to figure out how to reduce or eliminate it.

The only thing that I am not sure about is when you said in your question, "produces constant static".  Most people consider "constant static" as white noise that is always there.  But I think you mean "pops and clicks" that you hear frequently.  If you do mean pops and clicks then that is most likely still ESD.  If you mean white noise then you likely have a second problem.