On certain notes, I hear a brief electronic fizz or crackle at the attack. The fizz fades quickly, but the note itself continues to sustain normally.
I have a sound clip that I recorded on my phone and will try to upload it below. Guitar is straight in. No effects loop. The Marshall 1959 HW volume is on 7.
I have also noticed a strange electronic smell that smells very similar to my Ironman II when it starts to overheat. Not sure if that is normal.