I bought a AKG WMS40 wireless guitar system last year, and am having problems using it when the receiver is directly connected to a combo amp. When I connect the receiver to an effects pedal (typically my Digitech Trio) I don’t have any problems, but when I connect it to an amp (either an old Peavey Backstage or a portable Gorilla) I get no output from the guitar. Any idea why the WMS40 would have a problem when connected directly to an amp, but not when connected to an FX pedal?