I DON'T KNOW, we must have been listening to 2 different players because we could not tell the 8003 and 8001 apart in sound. And our 8003 had a much more quiet spin up than the 8001. This leads me to believe that it is probably unit dependent and poor quality control issues.

And as far as the SA15 is concerned, i've read reviews where the SA15 has a subtle better sound than the 8001. They question is, is it worth the extra money?