I hear it on my amp :S I really do think it's a nut problem... because it's happening regardless of my action. Also, I've setup my truss rod properly for sure so i don't see what else it could be.
Have a capo? Capo the first fret or just play all the first fret notes.
Do you still get buzzes when playing? What string? Play down the string what frets does it occur on?
A little feedback on what your trying may help.
You have to be methodical in your approach if you hunting for buzzy rabbits.
Yet again if the string plays fine open you are unlikely to have serious nut issues. Sometimes the first few frets when played put string pressure on the nut and if it has a obscure problem this can expose it.
I doubt getting a professional setup is going to make any difference for this issue. After all, it happened after i changed string gauges.
Famous last words. A guitar should be setup when you change gauges, sometimes you can get away without it.
But if your wanting help to do it yourself you need to provide precise information on what strings and what frets that string buzzes on.
Also it would help if you know that your neck has relief in it.
Such as capo the first fret then hold down the 12th fret and bounce the string inbetween on the frets to see if there is a gap. No relief and your more likely to have to have a higher action (string height).