Hi, I'm new here, and I have a problem with some amps.

I am trying to hook up one guitar to two amps. The guitar goes to a splitter, then one cord goes into the amp. The other cord goes through a Digitech RP-200 multi effects pedal, to a Crybaby wah, then to another amp. The first amp is plugged into one outlet, and the second one, along with both pedals, goes into another.

When I turn them on, there is a hum louder than the guitar signal itself. I read somewhere that it may be a grounding problem, but I don't know anything about electricity.

Any help would be greatly appreciated.
Welcome to UG.

So I take it you do not get that hum when plugged into either amp separately?

My hunch is that the hum is coming from the fact that you are plugging a MFX pedal into a Wah and then into an amp.

What amps are these BTW?

Try plugging the Wah in before the RP.

Is the setting on the RP you are using a high gain one? Try turning the gain down.

If the hum goes away when you touch the strings on your guitar then it is possible your guitar is not grounded properly.
Yep, no hum separately, and I actually went to the wah first, then to the MFX pedal.

A Line 6 spider 15, and a fender frontman 15,

the sound doesn't go away when I touch the strings. I'll try it out today. Thanks!
Well, MFX pedals don't take real well with a MFX amp like the Spider. Same with the wah pedal. Try running those into the Frontman if you are not now. If must have wah, you could probably pick up a used RP250 and use that instead. Wah's are pretty noisy pedals. Just sayin'.

Good luck
Thanks for your advice! I'm now running my guitar to the wah, then splitting one to the line 6, and the other to the MFX pedal then to the fender, and I am getting almost no hum at all. Thanks again!