Harmonic Tech AC-11/Mccormack DNA225/Adcom gfp-750

Is the Harmonic Technology AC-11 power cords one of the best to use with the McCormack DNA-225 power amp?
If so, why and what are the benefits?
If not, what brand would you rcommend for it?
Also, is the stock power cord adequate for the Adcom GFP-750 preamp or would you recommend an aftermarket one?
If you would recommend an after-market one, which one, and what sonic benefits over the stock cord?
The AC-11 introduced a hint of grain in the sound in my (non McCormack) systems.
I've had extremely good results with my DNA-225 using an Audience Power Chord. I tried some more expensive cords, too, but didn't hear any significant difference. A winner for the DNA-225, IMHO.
My experience has been similar to 4yanx with the Audience Power Chord--it mates extremely well with the DNA-225. Steve McCormack on his website lists several PC's that work well with McCormack amps, the Power Chord among them. Most cost more than the Audience, a few perhaps less, but the Audience has recieved positive reviews elsewhere as a great value. I've also seen a review of the Audience PC with the stock DNA-225, which was very positive, but I don't remember where I saw it. Perhaps someone else has seen the review and remembers?