Guitar processor noise...? BZZZZZZ!

Hey, some guys have guitars in their garages too? <My boy has a Digi Tech RP155 processor that goes between his Bass and the Crate BX100 amp. Holy smoke, this thing has developed a hellacious buzz in it! We can run the Ibanez bass directly to the amp and it cleans up 95% of the buzz but if you run it in series, forget about it. Does it on a Fender 15 amp too. Did I lose a ground on the input jack or do these things just go bad? Bass is a little buzzy too, Ill have to check that plug too and the cords are by no means new. Any buzz killers out there? The RP155 uses a 9vAC power in from a common brick, weird as I thought it would use a DC power supply for a cleaner voltage. processor is plugged into one power outlet (extension cord) while the amp is in another. processor is a 2 prong, IIRC the amp is too as these power jacks in this old house are not 3 prong unless I changed them out and I didt do this in the bedroom yet.