Jmcgrogan's comments are absolutely spot on. I will add the following. It has been my experience that the PC's that will make a clear difference (improvement) start at about $600 new, #300 used. I have had very good success with VH audio AirSines, Voodoo Cable (various models) and an Audience e. The funny thing is, its not terribly predictable. The Audience e was a really good PC for my ModWright Sony CD player, but was nothing spectacular on anything else. The AirSines were great on my Cary amps and Audio Magic Mini Ref power conditioner, but was not a good choice at all for my coincident pre amp. I have also used Signal Cable PCs and they are much better than 16 gauge lamp cord for sure, but really don't match up well against the other cords I have mentioned.
My suggestion would be buy one used VH audio Airsine used, rotate it through your system to see if you can tell a difference. If you can't don't go any further and resell the AirSine.
My suggestion would be buy one used VH audio Airsine used, rotate it through your system to see if you can tell a difference. If you can't don't go any further and resell the AirSine.