I’ve been teaching myself the Banjo for about 9 months now and I just recently did some maintenance on my instrument. I put on new strings, a new bridge, adjusted the head and oiled the fretboard. Everything sounds great now except the first string has an annoying loud vibrating sound (which goes away when I play with a capo). Which one of my actions could have caused this and how can I fix it?
That sound is known as a buzz. Buzzes can come from different places. The nut (0 fret) is a suspect because the buzz goes away when you capo. But the new bridge is also a suspect. Buzzes on open strings can often be traced to the bridge slot. If the edge of the slot, where the string exits to the fingerboard, is rough or ill-defined, the string is essentially bouncing on and off some hard material when it vibrates, and that’s what causes the buzz. The cure is to file (you need a special, very thin file) down into the slot to level off the “exiting” part, so that the string sits snugly at the edge of the slot, nothing to bounce on and off of. By the way, even under magnification, a rough edge of the slot is hard to see. But filing the slot down does work. If the problem is in the bridge, then probably the reason the buzz goes away when you capo is that the string is a bit more angled down, and fully seats in the slot. Also, be careful that the bridge is standing upright and not leaning toward the neck. Sometime in tightening strings, the winding of the 4th string kind of grabs the top of the bridge and tilts it toward the neck. That turns the end of the slot to another “bounceable” area, and the quick fix is just to retilt the bridge to its upright position.
Hope that helps,