Kurzweil PC2R Noise level on analog output jacks

I just received a Kurzweil PC2R that seems to work fine but there is a lot of noise on the output.
Plugged into my Keyboard amp and with the PC2R volume set to 0 I get a lot of noise on the output. When I turn up the volume the noise stays the same level. The patches play and sound good but the noise floor is too high.
Anyone seen tis issue?

Sounds like it could be a ground loop. Are your keyboard and amp plugged into the same power strip or are you using separate wall outlets? Try plugging both the amp and keyboard into a single power strip and that should help.