Hi guys,
I've had a digitech whammy now for a couple of weeks and I'm pulling my hair out with it.
When I first got it, it worked fine for about a day, I used the adapter that came with it, and no issues. After that, it started having this god awful hum no matter what I did. Even if I turned the volume down on my guitar to '0', there was still this hum. If I take the pedal out of the circuit it, the sound goes. So it's got to be the pedal that's the issue. So, I sent it back to where I got it from, they sent me a brand new replacement. The replacement, works fine for a day, and now it's got the exact same issue!!! This horrible crackling hum!
I've tried both my electric guitars with it, ones got active pickups, ones got passive, but still that same issues. The only thing I've been able to do is on my multi effects pedal I have a noise gate which i don't usually have to use, but I've turned it up to 6 out of a possible 14.
I don't know what it could be, like I said, without the whammy in the circuit, there's no hum, so I can't see it being anything else in my equipment that's the problem.

Thanks for any help you can give!

P.S - It doesn't need calibrating, trust me, i've done it a million times.
I have the same problem, but it just happened within the last 2 months. Ive had the pedal since september of 2010.