I'm a fairly new player (less than a year) and I purchased a new Zach Myers SE the past August after playing one for a bit in a local shop. After 4-5 weeks, though, I noticed a really bad vibration/rattle from the headstock when strumming a few open strings. I wish I could figure out how to describe it... it's a very hollow flopping/buzzing sound. Nothing at all like fret buzz, though. It is really noticeable on anything with an open 5th or 6th string, but noting that I can hear carting through to the amp. To make a long story short, I took it back to the shop I purchased it at where the techs spent about 2 hours with it. At first they thought it may be a bad string or a loose tuning machine. After a string change and making sure all the screws on the machine were tight, they started looking elsewhere. A list of the things I can remember them checking: - String change - Check the nut for tightness - Verified all tuners were tight. - Checked every screw/nut on the guitar for tightness including the strap buttons. Opened all the cavities and verified the switch, jack, and pots were all tight. Verified the pickups or the frames around them were tight and not vibrating. Verified the bridge and set screws weren't loose. - Checked two other ZM SE's they had in stock to verify they didn't have the same noise. - Added tension to the truss rod, then backed it down to the correct relief to ensure it was engaged against the wood. - Adjusted bridge height. After a couple of hours they both agreed the sound appeared to be coming from inside the neck, about 4 inches below the nut. Knocking on the neck doesn't produce any rattle. It seems to really show up whenever an E and sometimes an A is played. We were having some strange weather at the time (lower temps but really high humidity) and they thought that may have played a role. They suggested that it may go away as the weather continues to change. Needless to say, it hasn't gone away in a month and a half since. Some days it does seem better than other, but then other days it is very noticeable. On my own, I have changed the string again back to the original 9s (I had switched to D'Addario 10s after purchasing). It's driving me nuts. Again, as far as I can tell, doesn't make the guitar any less playable with an amp, but I still know it's there. Do you folks with more experience with guitars and PRS than I have any suggestions? Sorry for the overly long first post and thanks for any suggestions!