I just bought a used Ampeg SVT II Pro (which I love) but am now having problems with my SWR Goliath III. With my old amp (Ashdown Mag 600), the Goliath sounds like butter; with the SVT II, it sounds great except when I hit an F# (all of them ??!!??). I went to an amp guy I trust and we could not find any loose connections or microphonic tubes. I plugged my rig into another cabinet and it does not make the same noise. The speakers on the Goliath don't sound blown, and they sound great except on F# Anyone have any ideas? A loose connection in a speaker? I searched but could not find anything like this. Thanks!!