But could someone tell me why my 400+ has so many outputs? I understand impedance. But I thought that lets say you have two 8 ohm cabs, you plug one cab into the output of the other, and then that cab into the 4 ohm output of the amp. That is how its done, isn't it? Why does the 400+ have pairs of 2, 4, and 8 ohm outputs. I know why it has the 2, 4, and 8 ohm outputs, its the pairs that i'm asking about. Aren't you only supposed to use 1 output at a time? thanks.