Here's something interesting...
My JTV59 was fine out of the box - no plink. I played 3 in store and the other 2 had the plink. Too it home and played it - no plink. Played it at band practise - no plink. Awesome! High Gain, modelled guitar and alternate tuning - no plink. Acoustic model? No plink. Basically - I got a good one :)
Then I changed the strings...
I went from .10-.46 D'addario that came from factory to the D'addario .10 - .46 NYXL's. The bridge didn't get moved during the string change. I changed each string rather than taking all 6 off and putting the new 6 on. Was super careful not to disturb the guitar in case it gave me the plinks. Restrung, tuned to pitch, plugged in... magnetic pickups sounded sweet! These new strings sound wicked!... then I switched to modelled guitar and switched to baritone tuning...
AND I GOT THE PLINK - BIG TIME
I'm running Variax> Pod HD500> DT25. Plink made much more noticeable on any patch that uses amp voicing III. Moving amp voicing to IV quietened it enough that my band didn't notice... But I did.
I'll be switching back to regular D'addario soon and will report back. At this point, i'm inclined to think it's a hardware issue, as it only affects the thickest string, which I have noticed sits the most awkwardly in it's saddle, and is under the most tension - so MAYBE it's moving the piezo, and you only hear it when palm muting as the string vibration masks it when played open?
I know a guy who's also got this problem, and he SWEARS by wrapping electric tape around the string where it sits on the bridge to fix the problem. So i'll try that too.
Wish me luck!