I'm preparing to wire up my Martin Logan 60XTi's for passive Horizontal Bi-amping using a 400 II WOPL for the Low freq's and a 700 II WOPL for the high end or versa veesa. Martin Logan "Recommends" using 2 identical amps for passive bi-amping (They say DO NOT USE ACTIVE X-OVERS which I am NOT doing), and they say if you "Must use 2 different amps, they say you should use 2 amps with the same gain (or adjustable gain.... Volume knob's???) or gain characteristics. Being that my amps share the WOPL moniker, I figure that the designer utilized the same techniques when he designed them so I think they should be "More than close enough". ML was talking about a Sonic Imbalance could occur if using a Kraco amp and an amp that works would cause something like that. Impedances, damping ground schemes, volume pots, outputs etc.. are about the same after WOPLing so Damn the Torpedoes, full speed ahead............. Active Bi-amping is not in the cards so keep that in mind when commenting. Now that the weather is changing for the better, I can turn all these heaters and shit off so I got power to spare and I just had a dedicated circuit installed so I don't have any surprises when jamming and then somebody turns on the air compressor or the electric fireplace. I hate it when you lose power while listening to Bob Denver or John Denver as far as that goes........... SKIPPERRRR, I'm rocky Mountain High............