Can a power cord increase the resolution of an Class D (SMPS) amp by more than 5% ?

Please read Michael Fremer's short review of Audioquest Dragon Source power cords in May 2018 issue of Stereophile, and form your own conclusion....

mr_m

anyone who buys or considers buying a >3K power cord should have their head examined and fully deserve to have their wallet drained.

absolutely absurd that anyone would buy something like that!

Its interesting that no one has been able to measure what they claim to correct but somehow it can be heard.

I was at one of the local very high end audio stores listening to a pretty high end system, Wilsons, Audio Research and a Linn Klimax source.  The sales guys started doing something with the Linn asking me "do you hear that" then doing something again "do you hear the difference".  I did NOT know what was doing at that time and as it turns out could hear NO difference.  after 5-10 minutes of this he gave up and I finally asked him what we was  doing.  Turns out he was switching the ethernet cable with some unknown cable to a fancy, very pricy (no arrows though) >$500 CAT? cable. I started laughing because I really could not hear a difference and should not have.  I asked what the unknown cable was, CAT5? CAT5e, CAT6 and what there network was, 100m, 1g etc He DID NOT know and he didn't know what the fancy cable was either.  He claimed he can hear the difference and will be selling lots of them his customers who spend $25K on a Linn Klimax.

azbrd,

I totally agree with you. I have heard minute differences with some upgraded (and somewhat inexpensive) power cords. Most of that being tiny variations in (audible) frequency response. I was just bringing to attention to the large variation in SQ that Mr. Fremer claims to be hearing. It is most definite that I do not agree with him. But that is just my opinion. I cannot afford to dish out several thousand dollars for power cords and even if I could, I'm not sure I would....

I have heard minute differences with some upgraded

Could that maybe read "I think I have heard minute differences with some upgraded  (and somewhat inexpensive) power cords." 
If so bet in a blind A/B that "think" would be even more emphasised to the point of maybe the wind changed direction, or the amp came up to it's heat stable bias setting.

anyone who buys or considers buying a >3K power cord should have their head examined and fully deserve to have their wallet drained.

I  just looked at these and it's $5k for the 2mt one and $7K for the 3mt one!!!!!!!!!!

Cheers George 

IMHO, If one was to consider spending such funds on (1) AC cable per component, the superior choice would be to either hire a competent electrician or DIY (if so inclined) and have your AC wiring upgraded to multiple dedicated AC circuits, a new 300 - 400 amp service, new isolated ground, hospital grade, 20 amp receptacles and dedicated copper ground rods. One would probably have enough left over to include multiple data center grade double conversion ups’s, surge suppression in the service disconnect and a "sharpie" to write arrows on the romex cables. With the exception of the "sharpie" that is what I have done to connect my components to. It was a DIY project and cost about $6k, easily one of the best investments towards better sound I have ever performed. I also called my local power utility company when I installed the new service as they would have to connect their service wires to the new service panel, I showed the service guys my audio equipment. They installed a new transformer from the 3 phase power they provide and installed new copper wiring from it to my new service. I really lucked out on that one but I HAVE been paying their company over the decades. What I am trying to illustrate here is don’t hesitate to ask your power company for better AC power. Additionally, don’t forget to clean ALL of your connections every 6 months or so to prevent oxidation from building up. It will not make anything "sound" better but you won’t compromise anything to poor or oxidized connections. I get a "warm fuzzy" from doing this. YMMV.