I upgraded the umbilical between my Musical Fidelity XDac V3 & PSU V3 (In my PC Auio System) and the umbilical between my Squeezebox & CI power supply (in my main rig) both with revelation audio umbilicals and the results in each system were quite nocicable. The presence of music in both systems was more apparent, as well as transparency, depth of soundstage and a blacker background. If you compare the physical cables themselves, you will see a large difference from the stock cords. To me, upgrding the umbilicals was pretty much a no brainer, considering the small cost involved, as opposed to the cost of the rest of the systems. The results were quite worth it, to me. I upgrade all my power cables (including the squeezebox, CI power supply, etc), so I wouldn't overlook the umbilicals. A chain is only as strong as its weakest link.