radio on 2001 Chevrolet Monte Carlo

radio makes crakling noise even with the engine off. What could be the problem?

Asked by for the 2001 Chevrolet Monte Carlo
Is the key all the way off? if so it may be a wiring issue
yes key is all the way off. What kind of wiring problem could it be?
is it the original radio

yes..just had a new controller put in...could this be the problem?
could be since you did not have the problem before
Your welcome