I am trying to trouble shoot an intermittent noise that seems to be associated with digging in on the D (5th fret A) and its octave. If I hold the notes out for a while, they get the static as the notes decay. Once I get it going it is pretty pronounced but I gotta pick at it to get it started. I had problems with my HD-350 way back and thought maybe is was the head. But if I run it thru an Aggie 112 cab, no hiss. It seems to be when I run it with the Avatar cabinet and I have switch speaker cables. I turned the tweeter completely off and this helped but did not fix it. Does this sound like a blown speaker? I guess not given that the tweeter turned down seem to eliminate much of the hiss?