Odyssey amp,excessive hiss with balanced outputs?

I use a stratos amp and have always been satisfied with its performance. I recently purchased some zu balanced cables and noticed excessive hiss in this set up. I never heard this before with the rca's and the bv audio preamp is extremely quiet and recommends balanced outs to make it even quieter. I emailed Klaus to see why it would be more audibible and am waiting for his reply. Let me know if there is something I can do to fix this problem, or if you have experienced this type of problem before. Thanks, chip