Maybe try a different shaped banana plug? Some can be easier than others to work with. Or you could try and Crimp the banana plug your self using a pliers and make it fit!
If they are 5 way binding posts (they should be) you can unscrew the knob and use the spades directly on the post then clamp down with knob, maybe 1/8th of a turn with the pliers to really make them snug.
Matt
If they are 5 way binding posts (they should be) you can unscrew the knob and use the spades directly on the post then clamp down with knob, maybe 1/8th of a turn with the pliers to really make them snug.
Matt