I have never used any Logitech product but I used a CI VDC-SB power supply as an upgrade for a Trends UD-10.1 USB trasnport and it blew away the Trends optional recharable battery pak. For me in my system, an upgraded power supply has always been a very worthwhile tweak. Most recently, I purchased an Empirical Off-Ramp 3 with Superclock 4 and upgraded the supplied 12vdc wallwart power supply with a Paul Hynes SR3-12 power supply. It resulted in a nite/day improvement in clarity & resolution through out the whole frequency range, to a notable extent was the crystaline highs and textured lows. If a Paul Hynes PS can do that for a high end Steve Nugent PC audio product, there's no reason not to think that a Hynes power supply would do the same for any Logitech product (in my humble opinion).
Cheers,
Robin
Cheers,
Robin