Adrien, the front A and B terminals on your 750 can't be used for bi-amping(not that it would be of significant value anyway)because there're no extra amps involved. They're merely a parallel connection to the left and right front amps, primarily to allow connecting a second set of speakers(in parallel)to carry the same signals, and usually but not necessarily in a different area. The B terminals can also be used as a somewhat more convenient way of making a bi-wire connection(i.e. instead of having to connect two wires to each A terminal), but bi-wiring has no advantage.
