Fret buzz only on 1 string / 1 fret

[Jimothey]

I really need some advise please!!

I've just changed the strings on my P bass from flats back to rounds and now I've noticed that I now get fret buzz on the 3rd fret if the D string but nowhere else

I've checked for high/low frets with my rocker and they are fine no rocking at all, 

Could it be a difference in tension that  has caused the neck to convex a tad??............ 😀 

[chris_b]

I once had an E string that was badly wound and one of the winds was standing proud of the rest.

[Jimothey]

The strings were off one of my other basses and there was no fret buzz on it, its just a bit confusing................ 😕

[franzbassist]

Try removing and refitting the offending string, making sure it's well seated in the bridge, saddle and nut.  If that doesn't sort it try a different set of strings to see if that cures the problem.

Edited June 26, 2019 by franzbassist