Audio Research Ref 6 power cord

Has anyone heard an aftermarket power cord significantly change the sound of an Audio Research Reference 6 preamp?  If so, please describe the cord and what you heard.
Not an exact comparison, but I am using a Nordost V2 with my AR Reference phono 3. It made the background more black and improved the overall clarity 
Thanks for the link, randy-11. There's a reason I specifically asked if anyone has heard a difference in power cord with the Ref 6. I used to own an Audio Research Reference 75 SE. I heard a subtle but not ignorable difference much like jperry noted when I swapped a Nordost Red Dawn cord for the stock unit. Surprisingly, I heard an even bigger change when swapping in a Synergistic Black Quantum fuse. So, I guess I fall into the camp that cords and fuses can make a difference. I guess I felt maybe there would be a bigger change on electronics that draw more current, amp vs preamp for example. But I don't know that. And I have tried two different power cords with Ayre MX-R Twenty amps when I had them, and noticed No significant change in sound.
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Sain line power cable it's what Audioresearch uses the voice their equipment with.
I own the 6 and I also use sain line pure current p.c with great results

 Shunyata and Sain are the two favorites of ARC. ARC used Shunyata in their showroom and may still. I tried both Nordost’s Heimdall 2 and a Kubala Sosna power cord on my Ref 5se. I thought Shunyata power cords made much more of an impact. The Shunyata did not change the sound but reinforced it. Emphasized all the wonderful qualities of the Ref 5se. I have Shunyata Zitron Alpha HC power cords on all my gear and a Triton power conditioner.

Count me with the Sain Line fans.  I do also use the Synergistic Red fuses in my ARC ref6/ref75se combo, but the Sain Line cords are a more noticeable improvement.  I did not really get a boost from the fuses, but YMMV.  I have tried some other cables, but the Sain cables don't really change the frequency balance like some others, they just reinforce the natural ARC sound.
Tried a Synergistc Research Black Quantum fuse in the Ref 6. Not a subtle, but quite a significant difference, especially in the high frequencies. Less wooden, more crystalline, especially with piano. For the cost, I highly suggest anyone try one.
Im using the Shunyata King Cobra CX with a Synergistc Blue Quantam fuse in my Ref 6...

historically, Transparent cabling is a sonic match w/ ARC. Look into the Reference/Reference XL or OPUS models. The current is Gen5. The older MM2 series still holds up very well, especially, used/demo prices.
Happy Listening!
Thanks jafant. I haven't heard Transparent's power line, other than at shows, but I have heard their interconnects and speaker cables, and they are Excellent. 

Between Sain line systems power cord, Synergistic Black and Blue fuses, and cryogenically treated tubes, I think I pushed about as much out of the Ref 6 as I could. And it is Amazingly Good. 

I never was able to quite get the crystalline pure highs, especially with piano, from the Ref 6 that I could bypassed, and run direct, DAC to amp.

I did solve that problem and found an option more tunable via NOS tube options. And that is with a VTL TL 7.5 III. The Ref 6 is 95% what the VTL is, and at a much lower cost. But I'm willing to pay more for the slight improvement in performance.
I am using Transparent power cords. I used the same cord on a Ref 5SE and now with the Reference 10. It does lower your noise floor especially if your room is quiet enough to hear the change.  That brings out the subtle cues in the good recordings. I noticed more foot tapping after swapping from the stock cord.