I just purchased Cardas replacement cables for my Sen HD 600s. Wow what a difference! Bass tightened up and the sense of depth increased. My problem is that I made the mistake of buying only 4 ft of cable :(. If I purchased a 4ft Cardas - Headphone Extension cable, would the sound be degraded at all? I am using this with a Beresford USB DAC, and a Little Dot Mk III.