when I bought the amp, some of the pots were scratchy as hell. I cleaned them all with contact cleaner and replaced the od channel gain pot. When I use any sort of gain, or even an od pedal through the clean channel, there is a slight crackling noise in the ‘background’. Lets say I strum a chord using gain, as the notes are dying out I can hear, what can only be describes as a crackle, almost like a crackle on a radio station that isn’t quite tuned in.. The less gain I use, the worse it is.

any help appreciated!