Page 1 of Yamaha SW205

I have a Yamaha sub (connected to my Yamaha 620 amp).

When listening at lowish volumes I can hear what sounds like interferance (may be there at higher volumes too.. just cant hear it then).

Only had it a few months.. just got some cheap bainbridge 7quid phono connectors.

Is it worth spending more on a connector? would it get rid of this interferance?

Its not major.. just annoying now I know its there!!