Just bought some speaker cable terminated with the QED 4mm Airloc Banana Plugs. I'm connecting my Arcam Alpha 9 amplifier to Linn speakers. Problem: Plugs fit akay in Linn speakers, but will not at all plug into the arcam amp???? There seems to be a centre pin in the speaker socket which is far to large for the plug. My old cheaper cable had cheaper 4mm banana plugs which fit on the arcam ok. Any thoughts??