#1
when i pluck my strings when my fingers are on frets between 12 and 9 on the 2nd string, i get a kind of rattling feedback from the amp. Anyone know how to fix this?
My stuff

Fender American Stratocaster

Vintage Acoustic

Marshall AVT100X
#2
Sounds like it's just rattling at its natural "frequency." It's sort of like when you go into different studios, you have to change the drum tunings because maybe your tom makes the room resonate. All objects have a "natural harmonic" that they will vibrate at, it's impossible to avoid.
Looking for my India/Django.