Rick,

I am curious why you did this as a test?

The tone generator in the S900 is completely different than the PSR-2000.

Raising the gain, even with the master volume at 10:00 is overdriving the amp...you are bound to get distortion.

Your S900 is fine.

Ian
_________________________
Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.