So you want to keep the existing playlists, but not the music that goes along with them. Is there a word for metadata without data?

Maybe I don't understand what you're getting at, but this doesn't seem to make any sense. A list of music would seem to be useless without the music to go with it, at least on a device whose whole purpose is to play music.

I suppose this could make sense if the music files you have on your computer are of a better quality than what you currently have on your empeg's drives. But there's not really any way to automatically associate the track metadata on the empeg with files on your computer.