Well I had a Valhalla 1.5M that I use with my Tascam to record HI-Rez music, so that is the one I tried, but I ordered a 1 meter length.
It cost more than the clock! But I feel Valhalla cables will hold there value better than others mentioned and it is a very good audio sonic match with the clock!
BTW, the Valhalla is directional and I was surprised that the arrow should point towards the EtherRegen from the clock. It sounded better that way and was confirmed by the clock manufacturer.
ozzy