Power cable from Audio Research Ref 6

Don't worry about it.  ARC hand selects, tubes and capacitors among other items.  They more or less invented the high end. 

They are not going to leave you hanging with a crummy power cord.

Now, if you do have any noise on your AC line then the thing to do is to buy a medical grade isolation transformer.  I know one guy who got one for $75 but they will usually go for about $300.

See the comment from @dbarger here (11/22 6:30am)

 https://forum.audiogon.com/discussions/the-new-synergistic-research-blue-fuses/post?postid=1485146#1...

The stock cables with all the ARC kit I ever owned were purely generic, fine but easily bettered (although I only ever compared them to power cords costing $2K and up)

Yep, I have found it worthwhile to upgrade from ARC's basic 20A power cords for the 2SE Phono stage.  I put an Elrod Gold Statement on, and the entire presentation had better dynamic nuance and musical "intelligibility", plus greater harmonic development.  I would definitely challenge the stock ARC power cable and see what you think.

I bought a brand new Ref 6 from a local dealer about four months ago. It is every bit as good the stellar review Mikey gave it in S'Phlle a year ago. Now about your question; I find it weird and disjointed. Why would you buy a 14K pre-amp (assuming you are buying it new, but even used, same difference) and not invest some money in an after-market cord? I used the stock cord for maybe a week and yeah, it works. Life is short-I wasn't going to spend time comparing the stock cord to after-market pc's. It appears to be a generic cheap PC with a 20 amp IEC plug. Now I will play the opposite side just for fun; chances are good that with all of the capacitors and carefully regulated power supply circuitry, the PC you use with the Ref 6 is not going to make a night and day difference. I spent less than $500 from Archon for a custom pc with 20A IEC and about the same for a Triode Wire Labs cord for my Ref 150se amp. But to do it over again, I would have focused more money and effort on selecting a better IC between my pre-amp and amp. To be brutally honest-that is the critical link. My Morrow MA-6 is way over-rated and was a waste of $600. If anybody wants to buy the pos from me, pm me. 

I own all ARC gear, a Ref 5se, Ref Phono 2se, Ref CD7 and Ref 110 amp. I have tried a number of different interconnect and speaker cables as well as power cords. My favorite are the Shunyata Zitron Alpha HC. Sane cables might be slightly better. I did not have them at the same time as the Shunyata. They are very similar sounding. Both the Nordost and kubala-sosna cables I tried seemed to change the sound in different ways. The Shunyata is more like opening a window all the way. It does not changed the way my Ref 5se sounds but enhances it. One of the cables I did not try was Wireworld. I have heard good things about their cables with ARC gear.

  The Shunyata Zitron Alpha I have on my Ref 5se is a huge step up from the stock power cord. You will not truly hear what the Ref 5se / Ref 6 preamps can do with the stock power cord.