Hey guys, I have an RG1570 that has a weird rattling sound coming from the locking nut when I play the open low E and also on a lot of fretted notes on the B and high E strings. The sound doesn't come through the amp, just acoustically. I've removed a shim that was under the nut and made sure everything is tight and I checked the truss rod in case something was loose there... nothing. Any ideas what it could be? Thanks.