Originally Posted by KeithAlanK
Acoustic guitars always sound better with an instrument-specific preamp versus a regular direct box. For one thing, you won't be cranking the input gain way up on his channel, which sets you up for damage as described. Had a sub blown exactly like this.
In a (somewhat) related story...
I blew up the tweeters in a couple of monitors in an imaginatively stupid way. I had live mic running through the board in my studio into the monitors, and I was on a ladder running a cable overhead. I was pulling a cable, and I felt a little resistance, so I gave it a gentle tug.
The resistance was coming from where the cable was lying, which I discovered later was between a couple of trim pots on my mixing board. When I tugged on the cable, it turned one of the trim pots all the way down and the other one all the way up, and the latter one (of course) was the channel with the live mic, which immediately leapt into earsplitting feedback. It was a good five seconds before I could get down off the ladder and over to the mixer to shut it down, and by that time the high frequency drivers were toast.
Chalk it up to lessons learned.