electroman - it does reduce, when I turn the sub-down, but this was never a problem before - is it just that I have a much better and more sensitive cable now? Notwithstanding - should it still hum when the amp is turned off?
Beaverme - no idea what the old one is, how could I tell? one end isn't a straight plug, it's at a 90 degree angle, like some earphones are.