Hey guys I am experiencing something very odd with my amplifier. The amp seems to make this weird crackling noise on certain notes on the fretboard. They all seem to be anything c#. I play the 16th fret on the a and 11th fret on d and they all create this sound! I will include a video to demonstrate. I have tried other guitars and the same issue occurs. I have just plugged my guitar into the amp and ditched the pedals same problem. Experimented with pu heights, put the amp in half power mode, tried a different cable, and none of these seem to work! It is EXTREMELY noticeable on the clean channel and subtle but noticeable on the lead channel. I have a Marshall DSL40c, I am not the original owner, I bought this off of GC Used What can possibly be causing this?