Headphones problem switching from stereo to mono.

Okay so I chopped up my samples earlier. I load them on my pads but when I play them they switch to the right side of my headphones or play in both ears. Im using a stereo cord from radio shack. Don't really understand why its doing that. any suggestion?

Sometimes I've seen that happen when I'm using effects. Glitchy...

Having the exact same problem, any sound that comes out of my mpc only plays in the right ear..