Cannot plug my Subwoofer back in

This just happened Friday evening so I cannot call Sunfire until Monday. But until then, what do you think? I'm futs'n around on the floor near the subwoofer with the tuner on at a very, very low volume. I hear, not a hum but a strange sound coming from the sub. Shut the tuner off, and it sounds like, not a hum, but a airy hollow sound. Very low, but audible when close to the sub. Before this episode, always dead quiet while system on, and nothing playing. Can't hear this strange echoish sound when the system is on playing music and the noise doesn't change when the volume is raised. OK, so what do I do? I can't figure out what's going on. The sub has its own dedicated line and has been a very happy camper for 14 months. I pull the plug out of the wall just to examine and when I put it back in the wall: a loud vrooom from the sub. Dead. Check the slow blow 4 amp fuse in the back. Blown. Put in another fuse, plug back in: Vroom. Blown. OK, shut integrated off totally, plug sub into a different outlet with extension. Same thing. Keeps blowing the fuse. Sub is 14 months old. Never pushed. Anybody have an idea? Something for me to obsess about 'til Monday. Could I have a short ciruct or something like that in the sub? Any ideas would be appreciated. I'm not as depressed as I thought I'd be, YET. My Revels are holding their own. Thanks guys. peace, warren