Paul, I faced some weird speaker noise (static-like sound, volume loss); jiggling the speaker wires at the banana plugs was unequivocal, yea–nay? The banana plugs were screw compression-style. Straightforward, right? So I asked about. Redoing the wire-to-plug several times was a failure. 
The problem resolved with a set of banana plug speaker wires from Monoprice. Was it the banana plugs, the wire, the assembly? I dunno, likely the latter, I am not good with even the basics, i.e., wire stripping, soldering. Stick with it, members are here to help.