When you spend 6 days trying to fault find the nose issue you have, is it the instrument? Nope all good there, Is it the amp nope all good there also? Sound goes away when I touch the strings (grounding the system)
Leave it all plugged in to answer the door, turn off my lights and the noise goes away/comes back when turning on/off lights…it’s the lamp system in my house that runs on a separate 5 amp ring main well that was unexpected