Monday, June 13, 2016

Power Cords and Power Distributors

I'd be inclined to dismiss claims that good operating power cords have large audible differences when used to power audio equipment.  I'm not aware of any famous DBT tests which have "proven" this (meaning, proven to the skeptics, who I call objectophiles, such as those at Hydrogen Audio.   "Proving" it to subjectophiles means nothing since they already believe).  Although there haven't been many famous DBT tests of power cords, advocates of DBT will say that nearly every DBT test performed on amplifiers, preamplifiers, etc., and they assume that all such tests have negative results, is also a DBT test on the power cords those amplifiers, preamplifiers, etc., used.  There is some merit in that argument, as well as some of the others used by objectophiles to discredit the idea that power cords make consistent audible differences, and audible differences with particular "character" (so a particular cord may be described, for example, as either "light" or "dark" sounding, or "detailed," "grainy", or any of the endless subjectophile descriptions).  However I would not consider the usual "thousand miles of wire ahead of the outlet, why does the last 6 feet make so much difference" argument to be a meritorious argument prima facie.  There is no reason why the last 6 feet might NOT be important in some crucial way.  One obvious way is that of either making a solid continuous connection vs making a constantly arcing noisy connection.  I'm already giving away that I believe the contacts of a power cord to be the most importantly variable part.

One way or another there's no argument that, in principle, power cords are important.  Without power cords you aren't going to be playing anything.  So for sure a power cord makes that difference.

I now find myself in the position of rearranging a lot of the equipment in the living room, replacing the power conditioning UPS with a new one, and setting up new power distributors (power strips w/o surge protection) to extend the pitifully limited 8 outlets on the back of my UPS to power the 20 or so electrically operated devices in my living room A/V system.  So I'm rethinking the power cords a bit.

As is my nature, I'm going to get above average power cords just because I want everything to be above average, not that I'm convinced it's going to make a big difference, or even a consistently audible one.  But from where I start, the #1 thing is that the power cord make robust AC connections.

In that regards, I've never much liked IEC connections, except in that it truly is much easier to cart around equipment without attached cords.  And most of the cords used in the early days of audio (which I'm arbitrarily defining as before 1980) were pretty marginal quality, often getting damaged with the least excuse.  So IEC connected cords have some advantages, but also the supreme disadvantage that like plugs themselves the IEC connections can work themselves loose, and in some intermediate state of connection there may be waveform distortion or momentary power loss, added arcing noise, etc.

But my dislike of IEC connections goes only so far as to stay away from power strips with IEC connectors something which, btw, I consider an incredibly bad idea because of the potential for coming loose*.  I'm not actually going to modify any of my equipment to replace IEC connectors with attached cords (or at least no plans to modify yet).  I admit I remember when I started buying "real" audiophile equipment with detachable cords...and I though it was great to be able to move equipment around without being bothered by the cords, and then plug the cords in last of all.  So convenient.  But over the years I've observed IEC connectors sag in their sockets, much like heavy plugs do in wimpy outlets.  And this sagging can be squarely in the direction of pulling out.  I've never observed anything like arcing, but it seems to me the potential is there, and furthermore anything but a fully inserted fully horizontal connection is not the best possible connection.

Well equipment in a rack is one thing, you can reach back and easily check the IEC's when you are changing other connections, but power strips on the floor with horizontal inlets are far worse.  First of all any equipment on the floor should have it's IEC inlet above 2 or so inches do be clear of carpet and carpet padding.  Heavy equipment may compress the carpet and padding so that just outside the equipment the carpet immediately rises more than 1 inch, possibly pushing against the IEC attached cord and making it loose.  Also, a heavy stiff cord can, if other cords are piled on top of it, get pushed down and pulled out of the IEC socket that way (actually, this is the situation I have observed, cords getting pushed down and out by something else...usually another cord).

Sad to say, I haven't yet become the perfectionist audiophile who has all his cords neat and tidy on their own individual cable towers.  The first problem is I have waaaay too many cables.  I'm accused of having a too complex system.  Actually I may not think it's quite complex enough yet, but I'm working on it.

So sitting on the floor, imagine an audiophile power strip with IEC power inlet on the side.  This is an invitation for disaster as cords piled up on the connected cord begin pulling it out.  If the connector becomes sup-optimally connected and/or starts arcing, this not only affects one piece of gear it affects all those connected (and possibly those on other UPS outlet branches too) to the same power strip.  And it causes them to interact among themselves in response...which could possibly be the worst of all.

Serious UPS units always have an attached cord.  The Belkin UPS didn't but the new Panamax UPS does.  I think power strips should be corded also.

This gets tricky for two reasons.  Since my thinking on this isn't widespread yet, most of the audiophile strips and kits for sale are still of the detachable cord kind.  You really have to dig to find the ones with attached cords.  I have found two of note, the one by Chris VanHaus (at VanHaus audio) and the one by Patric Cullen (at Cullen Cables).  Another is the $79 Maze Audio unit which is clearly an upgraded Fellows cord, not something scratch built for audio.

There are also classics endorsed by audiophiles but not made for audio, such as Wiremold with no switch, fuse, or light.  I use two of those in my bedroom system.  I also use a similar Wiremold, the (amazingly expensive) hospital grade with metal box (of course) and no surge or light.  It *does* have a switch which might also be some kind of breaker.  The outlets are all real hospital grade duplex outlets which feel very tight.  I currently use one of those in the living room and bought another, both with 15 foot cords.  They will be used for the new racks of equipment along the north wall.

The other thing is that to avoid serious clutter, the attached cables should be the correct length.  Preferably this would be to the closest inch, but to the closest foot would be nice also.  That basically means you need to make it yourself or have a custom builder.  I suspect either VanHaus or Cullen would do that, and I decided on the less expensive 6 outlet Cullen strip myself, and it's getting a custom 3 foot cord (his standard was 4 feet).

Speaking of above average here is a pretty good (as these things go) subjectophile review of power cords that sounds like considerable time (years) and effort was put into it (of course, no serious methodology like DBT, of course).

We can assume that every such subjectophile review will be different, with a different set of cords rising to the top, and different pseudo explanations of what was going on (if any explanation is given at all...btw I think such explanations are part of the pudding and I would always prefer to have such an explanation...even if total nonsense...than none).

In this case the reviewer treats us with some other discussion about the useability of the cables.  That is a factor which is important to nearly everyone except audio masochists.  So at minimum there is at least some information here.  We know, for example, that the cords by Chris Vanhaus are very stiff and hard to twist.

Here is a short list of the cords I now have some interest in:

1) New Volex, the replacement for the legendary audiophile-praised Volex 17604 cords.  The original Volex cords that got audiophiles excited had bare brushed brass plugs and may have been made in the USA and may have been supplied with some early Levinson gear.  Volex cords were generally the standard for laboratory equipment such as oscilloscopes and wave generators.  The new Volex cords which may use the same part numbers now have nickel plated shiny metal plugs and are made in China.  So are they not as good?  That is the claim from numerous subjectophile sources.  However, they are easy to get brand new from Newark, Allied, and many other distributors, in a varity of lengths and sizes and configurations.  The audiophile praised Volex were shielded btw.  I've just ordered a bunch of brand new shielded Volex cords in 2 foot, 3 foot, and 4.9 foot lengths.  My idea is that everything that isn't going to get a "special" cord of some kind will get a Volex.  I assume they are well made and make pretty good connections still, just as they used to.

The shielding thing shows how messy things get when there is no objective testing.  Opinions are completely divided on this issue, with some saying that shielding is essential for the best sound and others saying exactly the opposite.  Some split the difference, saying shielding is good for digital equipment but not pure analog equipment.

Just for kicks lets see who takes which side:

Shielded Cords:
PS Audio (AC-3 and AC-5, among others, but I can't say every cord PS Audio has ever made has been shielded because they've been through many different cords in their decades of business).

Volex (17604 et al).

A2D solutions (who makes a power cord with a cable copying the design of the famous Belden 19364--a favorite of audio cord home brewers--which is also shielded).

Pangea (AC14, AC14 SE, AC9, AC9 Mk2 SE, etc)

Cardas.  Cardas has become more vague recently, and their beautiful diagrams of cable design are unlabeled, but I believe all Cardas power and speaker cables are and have been shielded.  Cardas seems to think correctly about a lot of such details.

Unshielded cords:

The cheapest cords are generally unshielded, so most cords provided by manufacturers are unshielded.

Kimber makes an unshielded cord, I'm sure there are others, but they are strangely harder to find than unshielded.

While there are non-trivial claims about what harms shielded cords could cause, it seems they can't be of much import seeing how at least half of the audio cord upgrade market is for shielded cords.

I know for a fact that my living room radiates considerable RFI and it's likely that most of this is from the power cords.  So I plan to use shielded power cords mostly if not entirely.

BTW there are many arguments on the shielding issue.  Basically you should know that shielding a power cord is not intended to protect the "purity" of the AC power.  The purpose of the shielded cord is to prevent the highly bursty nature of most current draws, particularly from switching power supplies, from strongly radiating to everything else.  What's being shielded is very high frequency current bursts.  Shielding is not very effective for 60 Hz power itself, I have heard.

Now the shielding in the cord should drain to the outlet side.  At that point it will arguably "contaminate" the ground...but it would also be contaminated by having the radiated energy from unshielded cords impinging on the chassis of the same equipment or others and draining back to the ground that way.  So you can't really win on this, but generally most designers of the most critical research equipment of the like will stick with the approach of shielding everything possible.  The most expensive tuners, for example, will shield every major subsystem from all the others.  This helps boost all kinds of spurious rejection.

So you can see, I'm a believer in cord shielding.  I'll take the New Volex as my baseline cord, and it provides shielding, as well as good quality connections and construction.  Nothing less should be considered.

2) Old Volex.  This was the legendary cord, which was made in USA I believe.  The plug tips were not polished shiny, they were brushed brass.  That was the way most cords were prior to the great influx of Chinese made cording.

I'll assume for the moment that there wasn't any significant change other than the cord ends, though that could be wrong.  But I'm sure many subjectophiles can relate to the idea that you don't want plated cord ends.

The usual stated objection revolves around the resistance.  It is widely quoted that unoxidized silver is the best (tarnished silver is a bit worse), copper next, then gold.  Nickel only has a fraction of the conductance (the reciprocal of resistance) of copper.

However the objectophile argument is definitive here.  The tiny bit of resistance going through a layer of nickel only thousandths of an inch thick cannot possibly be as of much consequences as going through many feet of copper wire.

The way I look at it the usual stated objection is simply wrong, but there's another situation entirely.  The important consideration is how well the contact area is managed.  This involves many factors such as how much pressure is applied over how much area.  How well does it stay (and can it be kept) clean.  How much remaining space is there between the surfaces and is there arcing and if so how does it work?

Analyzed in this way the situation doesn't get simpler, it gets far more complex.

Does a shiny nickel surface make better contact than a brushed brass one?  There's no easy answer to that, but as a first approximation is should not make any difference, because surfaces of the socket are not polished smooth, having a smoothly polished plug can not reliably make a difference one way or the other.  Often I find when plugging in the old style Volex cords I feel something like a self-wiping effect, which may help keep the plug clean and make a more "intimate" connection at the same time, slighly burying the plug surface into that of the sockets.

At the same time, old sloppily used old-style Volex cords are almost invariably dark from oxidation, pollution, and other factors and it is impossible to be satisfied they are ever completely cleaned off.  Nickel plated plugs can simply be wiped off, and you can easily get to a perfect shine with De Oxit.

In the end, I don't know, I do sort of like the "intimate contact" argument, but I don't really know if it's definitive.  Anyway, most audiophile cords don't give you shiny nickel.  The most common audiophile surface is gold, but there's also the brushed brass or copper (soft oxidation city!), and rhodium plating.  The Rhodium has the advantage that it doesn't wear off, is easily cleaned, and doesn't tarnish.  It's the most expensive option for Furutech cords, and many say it's the best.

But from a surface point of view, how flat the surface is, I'd think Rhodium to be essentially identical to shiny nickel plating.  They're both shinyThe difference between going through a thousandth of an inch of Rhodium vs Nickel is unimportant.  So if Rhodium is the best...Nickel can't be far behind.

Now with ANY sort of plating, I also wonder about the bimetalic junctions, say between the nickel plating and the underlying brass or whatever.  I wonder but I don't know how to evaluate these.  But I still believe the actual contact junction is the most important of all, and it needs to be analyzed and understood better.

Sometimes it is argued that the harder surfaces make better contact.  I'd like a better explanation of this since it seems to me that surface that wipe into each other, scraping off a surface layer of atoms or more, make better contact than crystaline surfaces that never deform in the slightest but retain slightly non-conforming shapes.

So I don't know but I have no personal fondness for the brushed brass or copper because I don't like the way it ages and becomes unsatisfying to clean.  But out of curiosity I have been looking on eBay for old style Volex cords in new condition.  I've never seen wear on any gold contact surfaces fwiw.  I have seen cheap gold plating corrode from underneath, but that's not the kind of stuff I'll be dealing with now.

3) Pangea.  I use the Pangea AC14 MkII SE for my subs.  The manufacturer doesn't actually recommend these for power amps, but mostly the sub isn't drawing much, and 14 gauge is OK I think.  It has to make a final sharp bend near the front door and I worried that the AC 9 wouldn't do this with a small enough turning radius.  The AC 14 is spot on.  It feels nicely made and all, and it certainly an option for my real front end devices.  Gold plated plugs but not fancy designer plugs...they look like glorified molded plugs.  The Cardas Copper is a big plus IMO.

4) Cardas.  I'm strangely tempted to buy a $500+ Cardas Clear M for my DAC for the Acoustats.  The DAC will not be plugged into any power strip, but into it's own dedicated outlet on the UPS.  And it should have at least a Volex cable if not better.  The Cardas Clear M powercable is all about reducing noise, radiation, and pickup.  I have enormous respect for Cardas.

But I would not be buying Clear M for everything, just what's most important.

But speaking of important, wouldn't it be more important to have Clear Speaker Cables ???  (Something till now I'd never thought of...just too far out I thought.)  Strangely the speaker cables seem far more expensive...partly that's because you need a pair of them?

5) Van Haus Flavor 1 for my low power devices.  But I read they're very stiff and require a long break in during which they have harshness that only slowly goes away but becomes transparency...never getting as far as warmth.

6) Morrow Cables?  The lowest end one looks OK.  The prices go up way too high quickly after that.  As with the Van Haus I think it's good to get solid IEC connectors like Wattgate.  Though I think the connectors in the Cardas may be best of all.

7) Cullen Cables.  I'm getting his power strip because it comes reasonably priced, and having 6 outlets is nice (two more than the VanHaus HotBox).  However only the most expensive version of his power cables, $199 for 2m, features actual shielding.  The lower priced ones are twisted such as to reduce noise...that's not good enough imo.

At $199 I'm within the price range of legacy Cardas, for a bit more I could have Cardas Golden Cross used or at deep discount.  Sadly I'm seeing now that the deeply discounted discontinued legacy Cardas is not available in all styles and sizes.  1.5 meter (too short, I think) and 2.5 meter (too long) are the typical old stock sizes.

I'd much rather have legacy Cardas (above the entry level crosslink and quadlink) than Cullen.  But if I were to limit myself to brand new cables at list price...this seems by far the best deal I know in the $200 category.  But that's more than I want to spend now.

8) Along with the original volex cords, another audiophile discovery was the "Iron Lung Jellyfish" cords.  Well that's a clever name for hospital grade cords with translucent ends, of which this MCM power cord was an indicated example.

Unfortunately the seller isn't clear about whether the cables are shielded or unshielded.  I used to think that the S in SJT and SVT meant shielded, but it apparently doesn't.  SJT is simply the heavier duty cable than SVT.  The "SJ" stands for Severe Junior (meaning 300 volts or less) and "SV" stands for Severe Vacuum as in a cord intended for use with vacuum cleaners.

I'm getting a bunch of shielded Volex cords for now, in a range of lengths starting from 2 feet.  I might decide on fancier cords later for select items.  But I need to get much more than just power cords for the new room rearrangement.  I also ought to prioritize better speaker wire above power cords, so I won't be getting any power cords above $200 before I get really good speaker wires costing at least that much.  Cardas Clear is an example of what I think is good speaker wire, but way over $200.

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