The tweeter in one of my aggie 112's started acting up last night (not to mention the tweeter in the other cab doesnt work altogether). Anyway, after about 5 mins of playing I start to get a high pitched kind of ringing sound through the tweeter. I just replaced the tube in my bass 350 a couple of weeks ago. Could I have gotten a dud or a bad tube? I really need your guys help on this since I have gigs on friday, saturday and next wednesday.