Why Power Cables Affect Sound

On another note, I recently bought some adapters and put a high quality power cable upstream of the wall wart power supply that serves my DAC. Wow! The improvement in sound was very impressive. Much more slam and dynamics. I recommend anyone to try this if they are plugging their wall wart start into the outlet. 

“...plugging their wall wart DIRECTLY into the outlet.”

The adapter goes from IEC to a standard NEMA electrical outlet style plug.

I’m just generally curious what is going on scientifically speaking. Furthermore, once we understand the phenomena then we can design and tweak to produce the results we want. For example, maybe the gauge of the copper fully explains the effect. If that’s the case then we can tweak that one variable and ignore the other ones that could use up our time and money.

Its easiest to measure the effect the cord has on equipment with which its used.

I’ve seen a power cord make a difference of nearly 30% of output power out of a power amplifier. I could also see that that was caused by a voltage drop across the power cord. This stuff isn’t woo voodoo nor is it any rocket science, its just Ohm’s Law.

You can measure differences in output power, output impedance and distortion on many power amps just by changing the power cord- and many of these differences are simply caused by voltage drop. IMO tube amps are more susceptible as they have a filament circuit that is unregulated, and the heat of the cathode makes a difference as to the transconductance of the tube. But a class A transistor amp is likely pretty susceptible too.


There is more to it than voltage drop though. It also has to do with bandwidth of the power cord as it has to be able to provide current at high frequencies because rectifiers in power supplies often commutate (switch on and off) for very short periods of time, and if the current gets limited during that current pulse the power supply can’t charge completely. A noisy, improperly charged power supply can have an effect on how a circuit performs. So it should be no surprise that power cords can have an audible effect.


The usual saw is why doesn’t the wiring in the house make a difference and the answer is that it does. Romex in general though is pretty high performance compared to flexible cable but its illegal to make power cords out of it.

Good stuff, atmasphere, thanks for posting. One thing I would like to explore is whether or not the power cable has to be at the amplifier or could it be at the breaker box. I hypothesize that it would have a greater effect at the amp.

Has anyone checked out the many rave reviews for Audioquest Hurricane power cords? Hel-loo! Maybe there’s something to this directionality stuff, highly polished conductor stuff and whatever else Audioquest has learned in the past thirty years. I know what you’re thinking, they’re just saying that because it sounds cool.