I just changed my strings, and whenever i play an open string there is a strange buzzing sound near the nut. Before i had D'arddio strings and I'm using Ernie Ball strings.
Does the sound come from the nut itself or are the strings hitting the 1st fret? Did you switch to a significantly different gauge? If the buzz is from the nut try lubricating the nut slots with a bit of pencil lead.