Hi Vitus4eva,

A crackling sound might be from the cable from your instrument to the amp, or a bad connection in the amp somewhere, it can also be from interference from any type of other nearby electronics, it could even be from your pickups!

This is so tough to figure out without hearing the sounds, and you mentioned there were other undesired sounds as well? What were those other sounds like?

Have you tried pluggin the amp into another wall outlet?

(I also moved this thread to Ask a Guitar Tech, maybe Stephen will know the answer!)