Best power cable to use for Raysonic 168?

Depending on how much you have to spend and what you think you want to improve I would look towards upgrading to Amperex/Mullard/Siemans tubes the Ray responds well to tube rolling and the sonic benefits would be greater than with a P/C. I run Amperex 6922 PQ US white lable( a pair of Phillips SQ miniwatt E88CC 6922) for sale @ $159 on AgoN the same as the Amperex's PQ. Food for thought.

I used a VD David 2.0 that was very dynamic but was to forward for my current system. I tried a Purist Aqueous Anniversary and found that to be a good combo with the Ray 168, it created a bigger sound stage, fuller notes,tightened the bass, helped definition and it even changed the CD's (kidding). It brought the Ray close to my CD3 MKll, I thought that was pretty fantastic!! I also tried the Purist Musaeus it had similar attributes to AA but to a lesser degree. What tubes are you using? Are you using RCA or Bal? What are you looking for a power cord to do?

I think that's correct, you can tell by leaving the outside tubes out for a moment, if you have sound your correct (won't harm unit I do it to check when I forget). I read that all four tubes affect the sound, with expensive tubes I run two and two cheaper tubes. My Ray came with EH-6922 and a spare pair of Jan-Phillips, the Jan-Phillips were better sounding to me! Once I heard the fullness of Amperex 6922 tubes i could never go back the sound is that much richer. It is a little daunting at first, here's are some good reference;

https://www.tubeworld.com/6922.htm some descriptions of sounds

also for prices;

http://www.audiotubes.com/bjtubes.htm

general descriptions;

http://www.audioasylum.com/audio/faq/joes-tubes.html

hope these help!

Take out "some descriptions of sound " that is my comment not part of the address!!