humming interconnects

I have a set of used Klyne dragonfly interconnects.

I had them connecting my new turntable to the Klyne pre -- and I was hearing a hum... so I checked the ground, etc.

I determined it was the interconnects -- the set I substituted do not hum and when I connected the Klyne's to the AUx -- the same hum.

any ideas how to fix or are these interconnects done for? what would cause this?

thanks.