Power cables for speakers, how much difference it makes

Question

I have some Audioengine A5+ speakers, and I've been reading from a number of sources that the out-of-the-box power cable is of inadequate quality, and that a $75 cable like the Wireworld Stratus would do wonders for my speakers. My questions are:

1. Barring pretty substantial resistance, which I assume is absurd for a power cable, how can it make a difference? Isn't the power output determined way more by the wall output than the cable?

2. What is this notion of "clean power"? I see it all over the place and I don't understand it.

Answer 1

Here's a pic of the back of the Audioengine A5+ speaker cabinet:

The power input is a typical 2-conductor removable power socket. The power cable will be your basic 16-14 gauge type like this:

These can be found for < $4 at just about any electronics store. There is absolutely no reason to spend more than that.

If the speaker has hum or noise on it, it's not because of this power cord; it's because the power supply inside the speaker is not doing an adequate job of filtering AC line hum, or worse, the speaker amplifier circuit is noisy.

"Clean power" generally refers to the output of an AC to DC converter, with respect to the ripple or noise on the line. (Video on ripple vs noise.)

It's possible to pick up noise from motors and other devices on the mains circuit, especially if they are physically and electrically close. (For example, a vacuum cleaner plugged into the same outlet or circuit branch as a stereo will usually cause audible clicks and static.)

The easy solution is to separate sources of noise by powering them from a separate circuit.

Wireworld's page on their power conditioning cables says this:

Wireworld power cords are designed to solve a completely different set of problems than audio and video cables. An ideal audio or video cable would pass the entire frequency range without alteration. However, an ideal power cord would pass only the 50Hz or 60Hz AC power, while blocking all higher frequencies, thus preventing power line noise and harmonics from degrading the sound and imaging quality of the system. Accordingly, our design objective and test methodology for these power cords was to provide sound and image quality that would be closest to the ultimate purity of battery power.

To achieve that objective, we developed Fluxfield Technology™, a unique internal structure incorporating Composilex® 2 insulation materials, which maximizes inductive and capacitive filtering to absorb power line noise and damp the electrical resonances that other cords and power conditioners cannot tame. Among the innovations of this design are dual low-impedance shields, which are closely coupled to the conductors to cancel unwanted energy.

Note the sentence "...closest to the ultimate purity of battery power." AC power, by definition, is alternating current, nothing like a battery, which is direct current (DC). There are a myriad of other suspect phrases in this, like "dual low-impedance shields."

Seriously, if you have AC line noise from other devices, there are cheaper and better ways of resolving it than getting an expensive cable that probably isn't a very good low-pass filter...

Edit:

If you really want to get something to filter the AC power going to audio systems, look at something like Furman power conditioners. They've been in the pro audio business for years, and the good news is, you can spend less than $75. For example, the Furman M-8x2 is $70 at Musician's Friend, and gives you eight outlets for your other audio/video equipment.

Answer 2

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Check out the reviews: ".. you get to see or hear the kit's capabilities more obviously. Stereo hi-fi equipment sounds cleaner, crisper and more articulate. The dynamics are more forceful but there's not a hint of exaggeration or excess".

Or this one:

"vocals had more texture and presence, the piano sounded more correct in timbre and the metallic texture of electric guitars and horns was smoothened (sic) out. With the Stratus, the sound quality became smoother and mellower overall, and harmonically richer"

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My personal opinion is that there is little justification for this stuff, it's got pretty much the same value proposition as women's jewellery. A lot of money for a pretty product that doesn't really do much except change the way the owner looks or feels about themselves.

On the other hand, there are some things that audiophiles can hear that normal indicators of THD and so on don't readily detect (in particular, Sigma-Delta effects), but I don't think power cables would be up there. The difference is that when the effects have been explained, you can set up instrumentation to demonstrate the difference, but that isn't likely going to happen with a power cord.

If you've got $100 to spend, and it's UL/CSA approved, the worst than can happen is that you'll be out $100, so it's up to you, but I would not do it. Keep in mind that this is an engineering SE, and things that are not quantifiable are not really engineering.

Answer 3

Barring pretty substantial resistance, which I assume is absurd for a power cable, how can it make a difference? Isn't the power output determined way more by the wall output than the cable?

The resistance that shouldn't be there is any difference in impedance from the AC line and common connection to the other devices' AC line and common connection. This induces noise from the power supply to float on the ground in an unbalanced line system (like above). The common practice for unbalanced devices is to use transformer isolation and not ground the chassis to the power to prevent "ground loops" forming. Balanced audio is somewhat immune, but will pass the common mode noise from the power if one side of the ac is not maintaining a low impedance connection. In these cases, I would look at the outlet first, because there are lazy electricians out there that just stab the wires in the back of the outlet instead of using the screw terminals, and have caused me problems in the past over this.

Well the potential power the device is going to consume would be determined by the size of the wire in the power cord, as well as the wiring going from the outlet to the breaker.

What is this notion of "clean power"? I see it all over the place and I don't understand it.

Clean power is power that doesn't contain any noise in it or is not induced locally by the equipment.

A Furman will not do anything for you if your outlets don't present the proper low impedance connection. It will pass the noise it can't shunt and the amount of noise would be proportional to the impedance of the outlet connection.

There you go, a scientific explanation coming from a 20+ year electronics tech, 10 years radio station engineer, and 17+ years dinking around in the pro audio scene.

...and yes the audiophiles and some audio engineers hate it because I do debunk the audio snake oil they have been spoon fed.... lol

Answer 4

If you’re going to go to these lengths then my opinion is make sure your gear is worth 10 times what your spending on cables or power conditioning. Most good hifi shops will lend you a good power strip, power cables and pre terminated speaker cables to try. The reason, most people with good equipment and good source material can hear the difference and then purchase them. I know, I know, I’ve read the science and it doesn’t support it and I agree from text book engineering. I went to a listening night the past week and listened to a power regenerator from PS Audio, the sound improvement was quite remarkable. Watch a video on youtube from Paul McGowan who owns PS Audio about power regeneration as compared to filtering and UPS solutions it explains a lot about impedance which most surge protection relies upon.

Really good power strips that have independent filtering per socket and individual power distribution can make a difference in removing noise from the incoming mains as well as power supplies you have plugged in for smaller equipment, for larger amplifiers you can suffer from a lack of power through them (in a big system you can be running 3500 watts plus of amplification). You can spend $1k on a power strip and 6 power cables. If your system isn’t $10k+ you’d be better spending the money either upgrading the speakers or most cost effectively putting some acoustic treatment in the room. There are companies now that will print photos onto acoustic panels so you room looks like you’ve decorated it and at the same time made it sound a lot better. My point is that you can do a lot for a smaller system before bothering going the power and cable route as they are small returns until you get high end equipment and source material. And even then have a listen to them and if you cant hear a difference don’t buy them.

I often find people who scream from the rooftops that power doesn’t make a difference don’t own high end audio equipment. It’s a little like having an 80’s Toyota and saying 98 octane fuel makes no difference, no it doesn’t, try running a turbo charged high performance vehicle designed for 98 octane on 89 octane, massive difference. It’s an analogy not a scientific explanation.