sounds like you have a bad ground. i had a similar problem, a little noise on a clean / empty patch, witch i didn't notice, but when i added a high gain amp like the tread plate i got noise as loud as my actual guitar signal. i found that my guitars internal wiring was frayed and wasn't providing a good enough connection to the ground side of the lead. this has the same effect as a bad lead so be sure to check your pod with your friends guitar and swap leads. also make sure that the power cable you are using is a balanced one so no charge is on the pods chassis. another quick test is to load up a patch with no noise gates and a high gain amp, then check the noise when you take your hands on and off the strings/metal parts of the guitar. if the noise level drops when you are touching the metal then the guitar is grounding through you which proves you have a grounding problem.
