I have two brand new Fender Jazz basses: one is a Deluxe Mexican Jazz bass and the other is a Geddy Lee... After I replaced the strings with a SLIGHTLY lighter gauge (GHS strings), my A string keeps buzzing. I heard that the string post (the thing that the string attaches to at the head) is making the string go too high. How can I fix this...because it's pissing the hell out of me!!! Oh yeah! It only does it when I'm playing an open note on that string....in other words, an A. Thanks.