I have a 2000 S1520 and I have just been recently having troubles with fret buzz. It is not as noticeable on the thicker strings as it is on the
high strings. I noticed it about a week ago, so I went and checked the
neck relief to see if it had backbowed or something bad like that. I measured at the ninth fret while fretting the 1st and 22nd frets and it was at about .5mm which I think is about ideal. My action is at 2mm on the bass and 1.8 on the treble at the 12th fret which according to Rich's site should be about right for a person like me with a pretty light pick attack. All this led to me thinking about putting a shim on the treble side of the nut cause the buzz is more noticeable near the nut, so i measured my 1st fret action and it was about .5mm. So, if anyone could share there wisdom with me that would be great.