I have this issue and I can't seem to find where it's coming from. Whenever I sit down to play guitar, I get this high pitched noise that's ringing in the background and it's really annoying. I mainly play single coils and know of 60 cycle hum but it's not that. When I'm in humbucker position, it's gone.

I sit in front of my desk where I have two monitors, my PC, my Audient EVO4, my mic which is muted most of the time. Everything is plugged into a power strip which is plugged into a wall outlet. I tried several different power strips and they all have this kind of noise.

I play through HX Stomp XL with 1/4 cable going into an instrumental input in EVO4. HX Stomp has recently been in repair and I mentioned this issue, though it also happened without it when I plugged in directly and used plugins. I tried different guitars and cables, even without a guitar, if I touch the tip of a cable it produces this noise.

If I play through Stomp somewhere else in the apartment using headphones, there is no noise.

I would assume it has to do with EMI since I have some lamps around me with smart bulbs and dimmers but I have this noise when they are all turned off and had it before when there were no lamps. Also saw a video that EVO's plastic shell can be problematic because it doesn't isolate from EMI but I'm not sure that's my case. I'm going insane with this noise, just want to play guitar and have fun. Does anyone know how to get rid of it???

High pitched noise when playing guitar