Well, before proceeding, please clarify exactly which keyboard you are referring to -- a PSR-550, or a PSR-S550 -- as these are two distinct keyboards. I do not have much experience with either (though I used to have a PSR-520, which was a very nice keyboard and is a predecessor to the PSR-550), but other people here likely have more information to provide. But we would need to know for sure if you're talking about the PSR-550 or PSR-S550.