That sound is identical to what I get with my pc speakers. My wire has been moved about too much and it has been damaged. It stops when I move it certain ways.
If the noise stops when you turn the software amp off, then I suppose its not that though, because it should still stay noisy. - but if you haven't, maybe try moving the wires.
If its when the amps are on, then it makes me think that its some noise getting in, and the increased gain of the amp or pedal before the amp is making it hearable.
I'd be interested to know if you have any noise gate on and if turning the threshold up, cuts the noise at all.
If it does, then it makes me think its some kind of noise getting into the guitar cable or the GX or usb cable. My first guess would be the guitar or usb cable.
The guitar cable could have got a bit damaged.
Also, its possible someone nearby is now running something which is sending out interference to your guitar's pickups or cable. Also, its possible this goes through the electrical outlet too and this can get right through to your speakers. I get this happening a few times every day. I don't know what it is but some noise affects my computer, stereo, radio etc. even when they are only on standby. I would look at that last though and get an electrician to see about that. Its more likely to be cables or connections somewhere.
Could you test it in another part of the house or try moving the guitar?
Does the noise happen when the guitar is being played or when the guitar isn't plugged in?
I found the problem. I moved to my parents house and there is no more noise.
I realised it's a problem occuring when my laptop is not connected to ground (earth).
In some old city appartments, plug sockets don't have the ground pin correctly connected.
My laptop is an old Mac Book Pro from 2008 and is made out of steel. When there is no ground, I can feel little electric charges by touching the body.
Thanks David for your answer.