I have a Line 6 ModPro, the rackmount version, and a Yamaha Clavinova keyboard (model CLP-511). I tried hooking the Line 6 effect box through the Auxiliary in/out only to get major noise. Just a beastly ringing that sounded like somebody threw all the volume knobs to unity gain. Does anyone have any idea as to why this happened? Or better yet, how I can hook the Line 6 up to my digital piano, if it's even possible?
It also has a headphone output...could this work? Or would I just be in for more squelching and screaming from an amplifier?