Newogger,
To answer one of your questions, I have recently auditioned the Audioquest Eagle Eye with 72V DBS, and it is very, very, good. But definitely on the revealing side of neutral, so I'm not sure if it's the answer, given your problem with edginess with the Krell DAC. I haven't auditioned the latest version of Synergistic Research Active digital, but the first X versions left me unimpressed with their colored midrange. Perhaps others could give suggestions for a good cable that's more forgiving up-top.
To answer one of your questions, I have recently auditioned the Audioquest Eagle Eye with 72V DBS, and it is very, very, good. But definitely on the revealing side of neutral, so I'm not sure if it's the answer, given your problem with edginess with the Krell DAC. I haven't auditioned the latest version of Synergistic Research Active digital, but the first X versions left me unimpressed with their colored midrange. Perhaps others could give suggestions for a good cable that's more forgiving up-top.