Swirling White Noise

[samgreene]

I had the gain and trim cranked all the way up the other day and turned a speaker off. This speaker causes a pop when it turns off. One of the preamps went into a bit of a strange static/white noise swirling sound which would go away when I turned the gain down and then back up. I then turned the preamp all the way back up and then clapped my hands in front of the mic, which triggered the same behavior. Granted, I had the input up too high for recording a hand clap, but this still has me a little worried. I didn't do it any more - and it didn't seem to do it in normal use over the last few days. What's going on here?