ARC Ref 3 Power Cord

Everyone here is using a different PC and some are relatively expensive. Why? What difference did these quite different cords make over the stock ARC cord which is quite substantially made? Did you purchase these cords for evaluation specifically with the Ref 3, or were they left over from previous uses? My only complaint about the stock cord is its excessive length in my application.

I use the Purist 20th Anniversary Contego Power Cord. I have compared it against the Stealth Dream, the Shunyata Anaconda Alpha Helix and the stock AR cord. My amps are the Lamm Ref 1.2 monoblocks. In my system, the Purist is a slight flavor improvement against the Stealth and Shunyata, and a significant across-the-board improvement against the stock cord. If you are using a Ref 3, you owe it to yourself to audition as many PC's as possible. These PC's are not cheap, but do make a difference. Just my opinion.

Audioesq, a difference, but what difference?

BTW, do you have dedicated circuits and/or power conditioning? It seems that the systems most influenced by power cords are those without any other power conditioning.

In over 30 years of using ARC amps & pre's, I have always found that changing the stock power cords afforded a significant improvement in the clarity and bass. I started out changing the old hard wired PC's as they deteriorated with visual surface aging of the natural [back then]rubber outer covers.
On the Ref 3 I changed to the Nordost Brahma, after trying the Nordost Valhalla. Brahma made a big difference, Valhalla did not.
However, Valhalla PC's were tried and kept in my phono stage, VPI SDS & SDS to VPI HRX motors, did make a very significant lift in the clarity.

Zargon,
I will attempt to answer your question.
I have eight dedicated 20 amp circuits in my main listening room. These are run from an isolated subpanel. My Ref3 is connected to its own dedicated 20 amp circuit. After running the Ref3 for about 650 hours, I compared the Purist, Stealth, Shunyata and stock power cords. All power cords were previously broken in with about 250 hours of current. Compared with the stock cord, the other cords were significantly better. As for the Purist, it allows the Ref3 to shine, with greater upper and lower frequency extension (about 1/4 octave, according to my sweep tone disc and my Rat Shack sound level meter), much purer tonality, much greater clarity, somewhat greater space between instruments and air, a sweeter yet more detailed presentation, a much darker (quieter) background, and overall more relaxed experience.
I have used these aftermarket power cords both with and without the benefit of dedicated circuits. Aftermarket power cords used without dedicated circuits offer greater overall benefit, but even with dedicated circuits are a significant step up from stock Audio Research power cords.
Your geographic location and power grid anomalies also affect the benefit of aftermarket power cords.