i have a question about my amp. it's an Ampeg BA115HP, and it's got a tweeter built in. My problem is whenever i hit an open D, (or the 5th fret on the A string) i get this hissing/buzzing kind of sound, which appears to be coming from the tweeter (i can't really tell exactly). I just had the amp serviced for all sorts of problems, including the tweeter, so i don't know if i should bring it back or what. I can't really hear it when the volume is up real loud, but when im practicing at home, it's pretty annoying. i also dont understand why it's only happening when i hit those notes. has anyone had this problem, or know how i can get rid of the slight hiss? any response is appreciated. thanks