A couple of hours ago, I hooked up my second HCA-750A amp on the woofers. This is a horizontal bi-amp configuration, but my crossovers are hybrid active/passive. My mid-range domes and the dome tweeters are still affected by the passive xover. I can't change this, unless I un-wire the drivers from the crossover. And then I'd need a three-way active crossover and a third amp. The ADS crossover point between the woofers and the mid/tweets is 500Hz. Above 500, the original passive xover is still in use (redundant info). The woofers, however, can receive any frequency the Rolls sends to the woofer amp.
I guess I'm by-passing the electrolytic caps as well as the bass coil on the ADS crossover. I'm not sure about that.
Anyway....I'd definitely recommend the Rolls for a two-way OB system. It's not ideal for bi-amping the ADS L-1290s. My speakers sound quite different, sometimes in a positive way, sometimes in a funky way. I'll come back to this. I'm going to try vertical bi-amping, which was goal after all.
Vertical bi-amping, at least with my equipment, means a two channel amp will be dedicated to each speaker. One channel will drive the mid/tweet, the other channel will drive the woofers (2 woofers per speaker).
More later.