I have a fairly new Shuttle 3.0-10T Combo Amp that I really love.............So I recently (about two weeks ago) added the STL-10T Extension Cabinet. I only had a chance to play the complete set-up twice, since I have been traveling. Each time I get a buzz out of the new extension cabinet, similar to a blown speaker, or a bad Neo magnet. Ironically, there are times it sounds fine?? I have tried various speaker cables, and nothing changes. I am currently using a high-end Monster 3 foot SP-1000 with Speak-On connectors. Sometimes when I turn the amp off, then back on the vibration seems to go away?? Like I said it has only been played twice, so I'm not sure what it could be.............I know that Neo magnets and Tweeters can sometimes be damaged in shipping, even with a new cabinet.............Maybe this could have happened?? Not sure how to approach this as I purchased it (and paid shipping) from a dealer on the opposite coast. These little extension cabinets are not cheap, so I want to make sure there is no issues! As it is now, the STL-3.0 sounds better by itself then when the STL-10 Extension Cabinet is added. I know there must be a problem, because the Combo Cabinet is so powerful on it's own. Thanks!