Question Static noise/hissing - desperate!

[steka]

Hi!

im Stefan, based in Germany, and I’m going mad over a problem I’ve been unable to solve since Christmas. I am trying to connect an external FRFR Speaker to my computer, and whatever means I use, I get a terrible static noise from my speaker.
The kind of noise that changes when the computer has any load, or when I’m touching the mouse etc...

this happens whenever I’m connecting the speaker somehow to the computer. Either by 3.5mm, or via USB via an Audio Interface.
plugging it into my laptop (connected to charger) doesn’t produce any noise. The speaker has a ground lift option which doesn’t change things

running the 3.5mm into my studio monitor speakers doesn’t cause any issue, also not when I’m connecting headphones etc...

tested so far

• Plugging/unplugging devises both from sockets as well as USB ports
• Making sure all audio-related hardware goes into the same socket
• Turning the plugs in the sockets
• Checked the computer main board for any lose connections
• Tested multiple sound devices. Amongst them a typical audio interface and a Helix guitar processor
• Changed usb and 3.5mm cables
• tested cinch to 3.5mm using the balanced outs of my audio Interface
• 
  
• 
  

As soon as I somehow connect my FRFR speaker or my guitar amp (through Helix or Interface) to my computer, I get this terrible hiss.
Really running out of ideas... anybody here has a good hint?

thanks!

 

[steka]

This is the noise i'm getting

View: https://youtu.be/6xap1fjXykk

 

[geofelt]

Is your main pc power outlet properly grounded?

 

[steka]

Hi,
thanks for the answer.

You mean the outlet of the power supply within the PC, or the wall socket?

i just spent 1 hour completely rebuilding the pc, switching also the PSU Cable - no change.

My studio monitors also have an external power supply and don't have this hiss. But whenever i connect my amp or the FRFR speaker to the PC by any means, i get this hiss....

 

[geofelt]

Wall socket.
You may have a case that does not ground well.
Take all of the parts out to see if the problem follows.

 

[steka]

I did, and i even changed the plugs i'm using etc...

I do not have this issue when connected to a laptop (same plug, and laptop is connected to same wall socket) for example.

 

[geofelt]

What is the make/model of your psu?
I might suspect that part.

 

[steka]

it is a be quiet 400 watt p11 model

 

[steka]

Tested a little further with my guitar plugged in.
The closer i place my guitar (pickups) to the power supply of my pc, the more hiss i get. Quite obvious...

 

[steka]

Ok, switched the Power Supply - same issue.