Hiss/White Noise persistent on Phones Out

Quad Cortex
1

On my QC I hear an Hiss/White Noise always present on Phones Out.
Try This:

  1. Turn On QC
  2. Create New Preset completely empty
  3. Disconnect instruments cables ( detach cable from QC, not from Guitar)
  4. Set Master Volume complete counterclockwise (0 %)
  5. Connect your headphone and hear…
    There is a hiss without connected.
2

the QC takes its ground from other gear- have you tried connecting it via USB or XLR?
Usually that’s more of a buzz than a hiss though.

3

Yes. I have connected USB and than also XLR to the mixer…
Nothing chage

4

Do you hear the hiss thru other outputs?
Are you set up to be able to record the sound?
What headphones are you using?

5

No thru other outputs there is no hiss.
Can I try to record but I’m not sure about results.
I use Audio Technica ATH M50X and Monolith M1060