So it's a beautiful day, and I'm out in the back yard washing my motorcycle. I've got the music playing on the deck, which has a subwoofer built in underneath it that is powered by a BKA1000 (which is mounted in a cabinet in the kitchen). I start noticing some crackling sounds coming out of the speakers, so I go inside to see whats wrong. The kitchen is filled with smoke, and it's billowing out of the cabinet! I open up the cabinet, and I'm horrified to see flames coming out of the top of the amps grill! So I quickly try to disconnect it and yank it out of there before it catches anything else on fire, and actually bet a little burned because it's so hot. I have to find an oven mitt to grab it carry it outside.
The flames were coming from the transformer, but the bulk of the crusted nastiness on the top grill is above the area where the capacitors are, so I guess maybe one of them blew, and either caught the transformer on fire directly, or caps caused a short overheating the transformer. The scary thing to me is the insulation of the transformer seems to actually support fire - I wouldn't have expected that. After I set the amp down on the countertop outside on the deck, I had to blow the fire out. Several minutes later after checking out the cabinet to make sure all is safe in there, the amp outside still has smoke coming out of it, so I took a picture of it:
It's really odd, because it's not under a heavy load. The music wasn't up THAT loud, and the sub that it powers will bottom out above 250w or so. The sub has two 2 ohm drivers wired in series, so it operates under a 4ohm load, well within it's 2 ohm rating. Previously, the amp has never even gotten warm to the touch, so I guess it's just a component that went bad and shorted. I REALLY hope it didn't dump a lot of current through the sub and fry one of the drivers. There's about 16" of clearance between the ground and the underside of the deck, so dismounting that thing and getting it out of there to replace drivers would be a huge PITA. I've ohmed the leads going to the sub, and the resistance fluctuates wildly between about 3.8 ohms and 24 ohms. I'm hoping that's just because the sub is acting like a huge microphone, providing current from various ambient sounds, screwing up the reading. At least it doesn't show open, or shorted, so I guess that's a good sign.
If there's one silver lining in the whole thing, I'm a pretty lazy procrastinating kind of guy, and I haven't tested my smoke alarm in many many years. And I also installed a new alarm system last year, and connected the existing smoke alarm from the previous system up to the new one, and never did test that. The alarm did go off (though after I noticed the problem - it took a minute or two for the smoke to get to the detector in the hall). And the alarm company did call me, so I guess I can now consider that system tested.
So just a caution to those of you who may have these installed in racks or cabinets... don't make sure there is plenty of clearance to combustible materials! I've got another buttkicker amp powering two buttkickers in the den, wired as a 2 ohm load (still spec). And that amp does have a wooden shelf above it, with about 2.5" of clearance. So I'm a bit paranoid now.
I guess it's time to see if Guitammer's customer service is as good as they say it is. The magic smoke is all over my house, and even outside, so I'll never get it all back in there.