Apple Cinema Display 20" hiss through headphone jack

[Riviera122]

I bought an ACD recently which was modded with a new, stock PSU, replacing the Apple one that it came with. However since using this display I get an audbile hiss when using the headphone port. How do I stop this from happening? I've also noticed that my laptop vibrates when plugging in the display.

My setup is:

Apple Cinema Display 20" plugged into a pair of power sockets
2012 Macbook Pro w/ separate line-in & headphone ports, plugged into charger using a separate pair of power sockets
Headphones

-Justin122

 

[Intell]

It isn't grounded properly.

 

[Riviera122]

It isn't grounded properly.

How do I fix this?

 

[RedCroissant]

Please post pictures if you can of the power supply and the wattage of the device in general and the number of items plugged into the same socket, etc. And which headphones are you using?

 

[MagicBoy]

As above.

Is the laptop plugged in using the extension cord or the duckhead adapter?

PS Thread bumping isn't allowed.

 

[Riviera122]

As above.

Is the laptop plugged in using the extension cord or the duckhead adapter?

PS Thread bumping isn't allowed.

It's plugged in using the extension cord.

 

[Riviera122]

Please post pictures if you can of the power supply and the wattage of the device in general and the number of items plugged into the same socket, etc. And which headphones are you using?

The monitor is a 2006 20" Apple Cinema Display. There are no other items plugged into the same socket as the display. The laptop power adapter is plugged into a separate display.

I'm just using regular Apple EarPods, however also intend to use active powered PC monitors in the future.

 

[Altemose]

It's plugged in using the extension cord.

Are you using any cords that lack the third prong at the bottom? For instance, I have seen some extension cords with only two prongs which would not be properly grounded.

 

[Riviera122]

Are you using any cords that lack the third prong at the bottom? For instance, I have seen some extension cords with only two prongs which would not be properly grounded.

I don't think so, it's just a stock extension cable.

 

[Altemose]

I don't think so, it's just a stock extension cable.

Try different power cords and also a different outlet.