hooked up my electric guitar into my wah and distortion pedals, turned on the amp and the distortion, started jamming, turned on the wah and all of the sudden I was hearing a local AM radio station through my amp. The freq. for the station was 1300. I messed with the knobs on the guitar, did nothing. Turned the volume knob on the guitar to 0, still getting the station. Turned off my distortion, still getting the station. Started rocking the wah pedal back and forth, started to changed the sound of the station. Turned the wah off, no station. Turned it back on. The radio station was there.
This is weird.
I always wanted to make a home made radio... I guess I finally kind of did it.
You are probably picking up RF through the power supply or PS cable for your wah pedal. You might try putting a ferrite core on the power cable right next to the power plug.
I had to do that with some powered speakers for my PC a few years ago. It can be really annoying. Especially when it's a RAP station or worse a Ranchero station.