Older Power Cables

"WAudio 3.3FT AC Power Cable 10AWG HiFi Audiophile Power Cord with US Plug IEC Connector" 

I'm not affiliated with the manufacturer/seller/online-platform.

You're going to have to try some new cables to find out.

I like SR's stuff, but have had good results with the higher-end GR power cables, too. (The GR cable took FOREVER to break in, so bear that in mind...).

@joscow - As mentioned above there have been significant improvements

1. metalurgy - e.g. UP-OCC copper - that improve details and dynamics
2. Insulations - low dielectric constant insulations that improve clarity
3. Cable Geometry - lowers noise floor and improves clarity and image

Take a look at Audio Envy or Zavfino - both reat cables

Regards - Steve

@classicrockfan - I was agnostic about power cables before I actually did some experimentation. My point of view was “I don’t know enough about the science to have a strong pov on whether different power cables would make a difference.” 
 

Now that I’ve experimented with a few quality cables, I believe they make a difference. That said, your system has to be resolving enough to hear what higher quality cables can make… 

I think the cables that have made the most difference would be Kimber Kable Palladian PK10 and Cardas Clear Beyond XL. I bought them used… could not afford them new! 

Been happy with my Magnan Signature PC's for many moons....