I know you said "power cord" but I’d rather just give you a lot of great info about cables and how to get the best possible sound. Read my entire message to learn...
Firstly, buy a "hospital-grade" power cable cord. Better than standard, cheap, or "reference" power cables. Why? they must be certified to reach a particular standard of operationality.
But why do cables sound slightly different? Inductance, capacitance, and impedance are specs that manufacturers can tinker with. And when they do, the sound invariably changes. (more bass/treble/midrange) they can tweak that. So your "reference cables" are now coloured sounding and useless.
A cable shouldn’t add anything to the sound. Short runs of cable always better if you can.
All you need are interconnects with PCOCC copper - was invented in Japan. The crystal grain structure is actually smoother and more linear than standard copper. Look this up...I’m sure you’re curious now.
PCOCC cables are ideal for connecting components together. But besides that, Furutech speaker wire and the cable that came with your headphones are fine.
No need to spend thousands, or tens of thousands. One really funny event - One of my buddies bought a cable with an "advanced filter" to improve the neutrality of the audio. We opened it up and a combination of foam and superglue were holding it all together.
Once we striped the wire, we found the cheapest and thinnest copper we’d ever seen...and tons of shielding surrounding it to make it appear to be a hefty and "high quality" cable.
But alas, I cannot teach anyone anything. I can only make them think. The worst thing that could happen is when people always go back to what they were doing previously, and failing; then blaming me for trying to help them.