You'd have to check all the specs, perhaps directly from the manufacturer. A few of the "Audio" buyer's guides have published damping factor, but sometimes it's hard to find. In my experience, amps that use bipolar output transistors must use a whole lot of them to achieve a better damping factor. Wheras, with MOSFETS, it's easy to achieve high damping, even with a lower current amplifier design. I decided the sound of mine, with its specialized Motorola bipolars, was the best amp I could get for the money...even though its damping factor is only around 50. Anyway, with a biamped setup, you shouldn't have too much trouble finding what you're looking for, and making it work.
