Time to replace it. A lack of ground is not only bad for sound, but potentially dangerous to the equipment. Without a ground reference on the input, your amplifier could output DC Voltages, which will cook your speakers! Get yourself another cable, perhaps one that isn't so stiff.
marigo cable failure
I just had a cable failure with my 8.8 Marigo interconnect taht seems directly attributable to bending. In oreder ot fir behind my equipment I bend the rigid cable and the outer conductor looses continunity. the cable still is stiff but I get a hum from the loss of ground. what say anyone to this? when I straighten the cable I've again got continunity, but I can't get it into my gear. cableman