hi, i was wandering if anyone could help me my Wah Wah makes a horrible hissing sound (can only really be described if you hear it sounds a bit like the ocean) when its not in use even if i turn the sound off on my guitar, the modle is a Boss PW 10 it is conected to my Marshall TSL half stack then the wah is conected to my guitar

anysuggestions on how to fix this problem would be apreciated
would you think a noise supressor would do the trick?

thanks Mike
From a quick glance, it looks like it has amp models. It may be a bit of fuzz that the pedal is adding.