Instructiuons on how to do this are given in the back of manuals for Mark Levinson 300 series amplifiers. You can get these by going to the Madrigal website (www.madrigal.com). For bridging you will need to strap the grounds together and have a "Y" connector made to go between your preamp and the stereo amp, with leads reversed. Bridging is tricky and may not sound well compared with bi-amping. If you have enough power from the amps, then bi-amping is the way to go.
Bi-Amping power amps
Which is the best method of biamping, using a pair of stereo power amps? Use one for each speaker (left to HF,right(with left signal)to LF, or the standard(?)left/right HF to one power amp and left/right LF to other. Or do you recommend something else (split HF, and LF of each speaker across each power amp to balance power draw? I have yet to try all of the above. Has anyone out there tried any of these options??