The action is perfect on my bass. Dead straight neck, no relief. But I have a buzz! It's only when I fret a C# on the B string - I checked with a straight edge and the 2nd fret is perhaps less than 1/4 of a millimetre lower than the 1st and 3rd. I don't think it can be heard much when the bass is amplified (but I don't know for sure because I can't turn it up loud), but it's driving me nuts because otherwise the bass is practically perfect. Any advice, or should I just leave it alone, shut the hell up, stop seeking absolute perfection and just play the damn thing?