Well it did cost you a PC you could otherwise have sold. But yeah, okay, I get it. Is this better than ordinary wire? Probably would be, I guess. But did you try it that way first just to see? How many Krissy filters do you have? If none or if that question doesn't even make sense PM, we need to talk. ;)
Cheap grounding solution
By chance I happened on a good use for disused power cords: Disconnect live and neutral leads at the power plug and connect them all to ground. Take off the IEC connector and terminate all to a single spade connector. On your DAC or preamp connect spade to grounding post or casing and insert power plags into a switched of mains socket, ideally on a different circuit. Alternatively terminate with RCAplug not connecting the centre pin and use spare RCA input on Pre or DAC I think you‘ll be pleasantly surprised about the increase in blackness, depth and height of soundstage as well as increased transparency. Total cost: zip squad diddely