Onkyo uses AB.Granted the 709 isn't Darlington on all channels (I don't think it is, think they saved that for the 809).On Onkyo (and Integra), the main channel is where Onkyos aren't phased by 3ohm loads. (If all channel Darlington, they'll drive an entire 4ohm 5/7/9 speaker set without breaking a sweat)Currently I'm listening to my 708 driving my DCM TF(granted, 92db efficient and 6ohm min) in a 35x35 room.The 708 is currently pumping along loud enough to hear SACD all over the house.By the way, my 1008 drives nine BIC V(830 main, 4 820, 62 and a 62 center) to a sweet spot spl of 110. That 110 isn't all it has either.(playing around once, dialed it back to 5.0...sans sub...center set 60, the 830 and 820 set full band. I got 118db using the Ode to Joy scene of Immortal Beloved)