Eliminating McCarty 594 body rattle


New Member
Nov 26, 2023
I have a brand new S2 McCarty 594 with a very noticeable metal rattle emanating from the body somewhere, but I can’t place exactly where. It’s on the GBE strings, every time any chord is played or the strings are barred. It doesn’t matter what notes or where on the neck, so I don’t think its sympathetic vibration. It sounds like its coming from around the two-piece bridge, more specifically the tune-o-matic. But I can’t seem to damper anything to isolate it. Also could be the humbucker or volume pots. It’s not coming from the neck. I have not looked inside yet. Any experience with something similar or suggestions on how to isolate and eliminate it?
I have had an actual tun-o-matic bridge on Gibson and Epiphone guitars rattle. That is usually centered around the type with the retaining wire on them. PRS isn't designed that way. I have never heard of the two piece bridge on a PRS having rattling issues.
I had not either, which is why I asked.

I forgot to mention the rattle doesn’t happen on individual strings or open strings, even if the open strings are strummed together. Just when fretted. That would make me think neck, but I swear its coming from the body and not neck.
Maybe one of the pickup mounting springs? I've heard of that happening before.
I've had this happen on a couple guitars over the years. Strum so you hear the rattle, then gently push down on one side of each pickup and see if it goes away. If it does go away, you can either remove the pickup and stretch the spring out to add tension or replace the spring with tubing, as used on Fender guitars. Good luck. Vibrations and rattles can drive a person cuckoo-bananas. I've also had a pickup mounting ring that buzzed/rattled.
I’ve had a vibrating pickup before too, but I was able to isolate it by dampening it with my finger to stop the vibration. I’ve tried pressing on the humbucker here, but it doesn’t do anything to stop the vibration, so I’m not sure if that’s what it is.

I’ve tried dampening the bridge, the pickups, and the volume/tone knobs by touching or holding them, but nothing seems to stop the metallic rattle noise and I can’t isolate exactly where it is coming from. It really does sound like it’s either coming from the bridge humbucker or the tune-o-matic portion of the two-piece bridge though. Is there anything inside the humbucker itself that could be vibrating besides the retention spring?

I read somewhere in reference to a Gibson two-piece vibration, that the strings could be set incorrectly in the bridge. Something about the ball being sideways, loose, and rattling. Not sure if that could possibly be the case here. I have not restrung it yet.

The guitar is brand new out of the factory box. Since I wrote the original post, there is now a second non-metallic vibration that has appeared on the bass strings (sounds like a whoosh) that I have isolated to the pickup selector switch. Touch the switch, and it stops. Not sure what to do about this either. The switch seems somewhat loose which I think is wobbling to the resonation of the guitar (the switch mechanism itself seems loose, not how its set in the guitar). Perhaps the way the wood in this guitar resonates is rattling and loosening up things that normally don’t rattle or loosen up, at least not this quickly. Surprisingly, no fret buzz at all and playability is excellent. I can still return the guitar, which if I can’t solve these vibrations, I’ll have to.
Man, that is super strange. I wonder if it could be a volume or tone pot that it rattling...

Is it the toggle in the switch or the entire switch that is loose? You may be able to take the plate off of the back and tweak the metal on the parts that it makes contact with to fix it. Does it rattle in all three positions?
I think it’s the plastic toggle, not the whole switch. The noise doesn’t sound like metal hitting. It only occurs in the center position, but happens everytime the E and A strings are hit. The center position seems a little loose.

It’s possible the metal sound is a volume pot. Touching the knobs doesn’t stop it though.
I would pull the pickups and look at the ground wire, perhaps it's not attached properly and is moving around? Longshot I know, but it sounds like you've eliminated the other usual suspects
What Is The Return Policy Where You Bought The Guitar? Warranty Claim it or Return It Is My Thought Unless It Is So Good It Isn't Replaceable. I Am Sorry You Are Dealing With Such A Thing. Very Frustrating Indeed!
You’re dealing with a sympathetic resonance. Finding it can be quite rewarding! You should pull the selector switch and examine it. Is there a lock ring? Is the switch broken? Do the tabs fully connect in the middle position? Look at each tuning machine also. Look for loose nuts. Look at each piece of your wiring harness. Do you have a loose connection? Investigate!