Issue with 1/4" inputs!

Hey so I'm working on a song right now, and I have my effects unit plugged into the two inputs on the back to record a keyboard track, and for some reason, the left channel is receiving a lot more audio than the right. I've switched the cables to see if that was the problem, and it's not. I'm hoping the right channel isn't going out on me. Any idea of what could be causing this?

Sorry if the question seems stupid, but have you tried connecting another external sound source to the Ren to see whether you have the same problem? This way you could at least determine whether the problem is caused by the Ren or your effect unit equipment.