One very easy thing to try - then determine if you hear a difference Connect your Speaker wires to the Upper set of terminals letting the jumpers feed the bottom ones - then reverse it attach speaker wires to lower terminals letting the jumpers feed the upper ones. Make sure you tighten the cables properly each time (this DOES make a difference)
If you hear no difference the jumpers do not matter
Good Listening
Peter
If you hear no difference the jumpers do not matter
Good Listening
Peter