Hi , Ive noticed lately a humming noise coming through my amp when my SR4 is plugged in . When i take my hands off the strings or body of the instrument it is making a hum , then when i touch the strings it stops . Also when i back off the trble "i think" it stops also . As if it were a live sound that isnt earthed or maybe not earthing . Does anyone have a thought on this and what would be the best way to fix it myself if its not too big a job . thanks !