A) For a 4-conductor Speakon to banana plug cable... The banana plug side has a "ridge" on the pole with the green & white wires. The other pole has red & black wires. 1)What does the "ridge" mean? 1) Is the "red & black" pole positive? B) For a 4-conductor Speakon to Speakon cable.. If bridging, does the amp side of the cable need to be modified, or can it be plugged "as is" into the amps bridged output?