Snake Oil! (part 2, power cables & conditioners)

In the previous post I talked about audio cables, and how there really can be audible or functional differences between them, even though you can’t believe the manufacturers’ claims.  The same is true with power conditioners, but unfortunately with “audiophile” power cables and outlets, there are no facts supporting the claims around those products at all.

The proof against audiophile power cables and outlets is easy and clear.  Nearly all powered musical equipment runs on DC power internally—the power from the wall is converted from AC into DC immediately, before the power connects to any part of the audio processing.  Sellers of special power outlets and cables rave about how their products correct the phase of the power, and smooth or filter any irregularities in the AC waves—but DC doesn’t have waves! DC doesn’t have phase!  It doesn’t matter what those outlets and cables do to the AC, because the power is converted to DC before being used, and any changes made to the AC are completely eliminated in the process.

Additionally, most electronics already include noise filtering in their power conversion circuit.  With the exception of a tube amp or preamp using AC to power the tube filaments, there is literally no way that these boutique power cables and outlets can have any impact, audible or otherwise, on the operation of your gear.  And even in the cases where AC is used internally, there are lengths of thin wire carrying the power from the external cable to the internal components, and these wires essentially undo any benefit of the thick, scientifically-braided, phase-corrected external cable.

You’ll see plenty of testimonials supporting these products because people do convince themselves they hear differences, but in every case it is just placebo effect.  The only thing you should look for in a power cable is sufficient wire gauge, and decent construction.  Inadequate wire gauge can perform worse, so if you want to upgrade from a flimsy factory-supplied IEC cable, just get one with thicker wire gauge (inside the insulation).

Power “conditioners” are tricky business, like audio cables.  They do perform a legitimate function, and there are differences between them; but again the manufacturers and sellers of these products make such outrageous claims about the supposed benefits of their devices that you really can’t believe a word of it.

Most conditioners are just a strip of outlets, like a cheap power strip you’d buy at a hardware store, with some simple noise filtering and surge protection.  The amount and quality of the noise filtering is usually not any more or better than what is already built into the equipment you’re plugging in.  Only quite old, cheap, and home-made gear may not have any built-in noise filtering, and would benefit from the filtering in the conditioner.  And the surge protection, while useful and completely valid for all equipment, is usually not any better in a $200 Furman or Monster deluxe power conditioner than it is in a cheap office-supply outlet strip.

Note too that the surge protection components in all of these devices are self-sacrificing, they self-destruct when hit with power surges.  So a $200 conditioner becomes almost worthless after only a few surges–but you’d never know it externally.  There’s no smoke or indicator light telling you that the device is now just dead weight in your rack.

The main actual benefit of a rackmount power conditioner is that it conveniently mounts in a rack; but you can easily screw a regular power strip onto the back lid of any rack.  Some of these devices come with lights or outlet testers, and those are fine but they are also available more cheaply in other forms.  Some may have sequenced switching or isolated outlets—those are among the few features that I feel are actually worth paying for.

Many people believe a power conditioner will correct any problems with low or high voltage from the wall, but that is false.  Of course the manufacturers lead you on with those beliefs, talking about the “clean and pure” power their conditioner will deliver; but they are just weaseling around with misleading words.  A power “regulator” will provide that voltage-leveling function, but those cost at least twice as much as a power conditioner, and sometimes quite a lot more.  Additionally confusing the issue, in earlier decades the word “conditioner” was used to mean a regulator, but that hasn’t been the case in a long time.

Making matters even more difficult, power regulators and conditioners can limit the amount of current available for your equipment to draw.  For most rack gear, keyboards, and other electronics, the current available through a conditioner is entirely sufficient; but a large amp, especially a high-wattage power amp, needs to be able to draw a lot more current than a typical conditioner can provide.  So you can actually downgrade the performance of your amp by plugging it into a power conditioner.  Many amp manufacturers recommend against using conditioners for this reason.

So what do I recommend?  Run your high-wattage (high current draw) items direct from the wall, unless you get a conditioner that states it has a high current capacity.  Don’t pay too much for a conditioner, when a cheap outlet strip is just as good in most cases.  If you need lights, get a clip-on book light.  If you need an outlet tester (which is a very good idea!) get one from a hardware store–they are small and inexpensive.  Sequenced switching is useful for making sure you don’t send loud power-on surge “pops” through your speakers, but the same thing can be achieved by just switching your power amp on/off by hand separately (you just have to remember to do it).  Isolated outlets can be beneficial, because different devices are designed with different grounding (earthing) systems, so sometimes ground loops or other noise problems can show up if two devices share a common ground.  Not every device or rig will benefit from isolated outlets, but it can help sometimes, and it can’t hurt—so I do look always for that feature.  The TrippLite Iso-Bar product line has isolated banks of outlets, and they are well-designed in general, and you can find them at reasonable prices on Ebay.  No snake oil, just honest verifiable functionality.

Share Button


  1. EdT said,

    April 30, 2010 @ 10:23 pm

    The amazing part of this mind-trick placebo effect that skeptics attribute to nerdy audiophiles is its consistency, even over years of listening to various systems and configurations, in providing an audible sense of difference between various power chord designs when supposedly there is none.

    I’m beginning to suspect that those who claim they can hear no difference between a stock power cord and a well-designed after market cable installed in for example, the source playback of a high-resolution system, are actually themselves the victims of a placebo effect.

    In other words, because bench testing equipment doesn’t register a difference, they refuse to accept that they could possibly be hearing a difference..

  2. Cyrus said,

    May 1, 2010 @ 12:31 am

    This comment above is exactly the sort of groaner that causes me (and other sensible people and engineers) to pull our hair out, and write articles about snake oil. While it is absolutely true (as pointed out in one or two of my posts) that expecting to NOT hear something is just as much of a bias as expecting TO hear something, that does not logically annul the results found by double-blind testing. It is in double-blind tests that audiophiles were found to be unable to hear any difference.

    Audiophiles get their knickers in a wad about blind ABX testing, claiming that the test mechanism alters the perceptions of the listeners, therefore skewing the results–but this is no different than the “psychics” who can’t predict or mind-read anything if they are being tested. The “consistency over years of listening” to the various power cord applications is utterly without merit, because no blind ABX testing was done by those listeners. They carry their biases around with them, just like the wine connoisseurs I mentioned in Part 1.

    Also, while there certainly are “real” auditory effects that do not register on crude test devices, the simple fact is that filtered AC is not used anywhere inside 99% of your audio gear. You can pour holy oil over the cables, and line them with crystals, and do anything else you want, but that power gets rectified into DC and then filtered, such that absolutely NONE of the wave qualities of AC exist any longer. Whatever fixing and cleaning was done to the AC has just been wiped away by a transformer and a diode bridge; and this happens right at the entry point to the chassis, before the power gets to any of the audio processing in your amp.

    In other words, your subtly-snide attempt to put down skeptics is sadly misguided, and informed only by wishful thinking. You now have a choice: you can study the science of verifying repeatable events, or you can put your head back into the sand, and blissfully enjoy your power cord.

RSS feed for comments on this post · TrackBack URI

Leave a Comment