So I thought it was a cable and changed it out but the noise in the loop was just too much. Turn the output down to where the hum is bearable and I lose most of the effects. So I solved the problem by turning the loop off running what I can through the front. Plus I’m splitting the signal into the kemper. It has plenty of effects. Done.
The effects and amp, are they plugged into an outlet on the same side of the breaker panel? If yes, maybe try separating? Breaker panels usually run one leg down the left, and the other down the right. Usually same side is the most quiet