I recently replaced a Cable Solutions Canare LV-77S digital S/PIDF cable with a DH Labs D-750, and I think I heard an improvement right off the bat, even though the LV-77S had the benefit of several days of break-in. The DH Labs was recommended by The Cable Co.
On the other hand, I wasn't impressed with the DH Labs Silver Sonic BL-1 iCable, with a 1/8" stereo plug on one end and RCAs on the other. It had the channels reversed, and it didn't sound any better than a basic cable of a similar length and type when used between my Dragonfly Red USB DAC and my stereo system. I haven't done the comparison yet with the Dragonfly Cobalt--maybe a higher-quality DAC will reveal some difference.
A Cable Company representative said that the room for the 1/8" plug is so limited that there's not much that can be done to improve it.
Has anyone else found a superior 1/8"-to-RCAs cable?