I was having some crackling issues with a bad cord or loose jack, or something. (I have an Eden D210-XLT) There was some amazingly loud noise like glass breaking at one point. The tweeter does contain a little red light bulb that I guess draws extra power so as not to overload the tweeter. The light bulb did NOT shatter. Now, I'm not sure if the tweeter is still working though. The sound is a little duller, although maybe my strings are getting older, or it's my imagination, or whatever. I tightened the jack, and use different cords now. What test can I run to see if the tweeter is functioning properly?