I have a Julius Keilwerth ST90 tenor and the neck octave key causes a strange "breathy" sound for everything from high A and up. It's worst on the A and not so bad on the higher notes, it sounds like a leak but I've tested all the pads, and that's not it. I know it's the octave key because I do not get the breathy sound when I play the higher octave by lipping up, and all notes using the G octave key are great. I've been working my way through a number of hypotheses and have come to the conclusion that I really don't have a flippin' clue what's going on here. Is this a known issue to anyone, or should I just take it to the tech?