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Headphone interference when charging.

TunaSurface

Active Member
This problem only occurs with Koss The Plug's. When I plug them in I'm okay, but when I plug the charger in I hear this low bass sound. It goes away when I even faintly touch the surface anywhere.
What is this? How can it be fixed?
 
That sounds like a possible bad ground in the outlet the charger is plugged into. Just a WAG.
 
But it's the wall socket I'm referring to. Grounding feedback is a common issue and may affect more than one wall outlet.

Some surge suppressors have a ground fault light on them that would tell you. There are also small yellow circuit testers with 3 lights on them that will diagnose a problem with a ground/fault.

If you have a device with only 2 prongs the general advice is to reverse the plug. This is a problem widely experienced on another forum. It could be feedback from something else on the circuit as well.
 
The Surface power supply does not have a ground lead. So to drain off any static, it uses a balances drain resistor set to the power line. So if the unit is setting where it is insulated, it is setting at nearly 1/2 line voltage. On the US 120V system, you may actually measure over 50VAC on the chassis. On a Europe 230V system you may see over 100VAC with it floating.
Touch the cabinet, and it drains that away through you body. That slight current can look for a path through anything that is plugged in or touching the unit. Reversing the plug doesn't help because it is balanced.
Doesn't hurt a thing, because the current is so low, but it is a poor idea IMHO.
 
So is there anyway to get rid of this problem, Instead of my hand, can I put something else on the Surface?
 
This problem only occurs with the certain earphones though.. weird :(
I'm thinking it may be an issue with the shielding of the headphones. True that noise is introduced by connecting the charger which with some headphones is properly rejected. by touching the Surface you are in effect squelching the noise. Do you by chance have a grounding strap from some previous product purchase... you could try connecting that to ground and the surface when you connect the charger. the Center screw of the outlet should work as a ground.

Something like this http://www.amazon.com/Belkin-Anti-S...pebp=1436975660557&perid=02PP118HY44HSVJVSRDN or a straight hunk of wire but the grounding strap would be safer if it works.
 
If the Surface is resting on a desk or table an antistatic Mat may work but they are more expensive and I'm not positive the higher resistance of the antistatic mat/strap will effectively eliminate the trouble, you will only know that from testing it. however the antistatic solution is safer than a hunk of wire because of the inherent resistance and in essence we are adding a ground to an ungrounded system design. The risk is low but in the event of sparks with the hunk of wire it just confirms an electrical issue that should be addressed by a "qualified" electrician.
 
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If the Surface is resting on a desk or table an antistatic Mat may work but they are more expensive and I'm not positive the higher resistance of the antistatic mat/strap will effectively eliminate the trouble, you will only know that from testing it. however the antistatic solution is safer than a hunk of wire because of the inherent resistance and in essence we are adding a ground to an ungrounded system design. The risk is low but in the event of sparks with the hunk of wire it just confirms an electrical issue that should be addressed by a "qualified" electrician.

Not TOO expensive I would think...

http://www.newegg.com/Product/Product.aspx?Item=N82E16899261021
 
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