Hi Squeak,
you may want to try and listen to one before you buy.
The earlier models QY10/20 ( to my ears at least)weren't on a par soundwise to the keyboards of that day. It wasn't the sound quality that you were paying for but, the portability and functions.

One thing I always did before I bought a keyboard , workstation , whatever, was to try and read the manual, just to make sure it was going to do what I wanted. I always thought of the QY's as a mini workstation.

best wishes
Rikki