Thanks, Sonicus.
It's good to know how to bridge the amp channels. But I use it with 2 speakers anyway, so that may not be necessary. Plus, the manual says it wants to see 16-ohms when bridged, and neither of my speakers are 16. I did make a special speaker cable to wire them in series, to make a single 16-ohm circuit, but I doubt there's a benefit to wiring it that way when I could just use both channels, one for each speaker.
But now that you mention it, bi-amping sounds interesting. Does anybody do that for guitar? What would be the benefits?