Dennis, I use the mono stuff with the old Solton MS 60's, and don't notice much of a problem. When I need stereo (like with the SD-5, and Midjay (when I start to use them), I'll use the Yamaha head, which is stereo. I used two channels on a mono head once, and pianos sounded better. I'm sure the stereo thing would be a bigger issue with different equipment. I also usually use the pianos from an old Yamaha tone generator and controller on top of the MS-60's into their own mono channel and that seems to work pretty well.

Russ