Well, I tried experimenting with it a little this morning. It looks like the limiter is protecting the power output section. I can turn down the preamp gain and turn up the output, and it still happens. If I max out the preamp gain and turn down the output, it doesn't happen. And it only seems to happen when the upper midrange and treble frequencies are very loud, I can't get it to happen when I turn up the bass. Very interesting. I may ping Walter about this. It happens on both channels, and I'm sure the amp is working fine and this is the way it's "supposed to" behave. It only happens with that one bass (so far), and the reason (probably) is that it has so much high end output (when you dial up the controls), to the point that it can hurt your ears when it's dialed all the way up. I'd never do that in real life at a gig, but I suppose the people who are running 18's or something without much high end response might try to turn the treble way up, and I'm guessing this just protects the amp under those conditions.