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Jurgenvanes
07-06-2004, 10:09 AM
Hi,

Iím thinking about modifying the standard powercords of my NAD C370 integrated and my NAD C270 poweramp. I want to remove the original cords and mount a suitable socket so I can connect decent quality powercords.

Does anyone have tips or suggestions?

Cheers.

Resident Loser
07-06-2004, 10:29 AM
...There is not a single shred of credible evidence that IEC-type power cords contribute anything whatsoever to a systems' sound.

The IEC cord was adopted solely for economic reasons and as a result a new cottage industry was spawned based on the gullibility and the never-ending search for the grail among audiophile types.

You could seek out sites to obtain retro-fit female connectors, but most will require extensive modifications to back panels at the very least and possibly to the PCBs within the units to be modified; say goodbye to any warranties. Safety issues may also arise.

And of course we have the requisite question: how do you think six-feet of powercord will undo any gremlins unleashed by the powerplant itself, line transformers and un-shielded service feeds that supply your mains? Think about it.

jimHJJ(...expensive snake oil IMO...)

gonefishin
07-06-2004, 11:40 AM
Hi Jurgenvanes,


Funny you should mention that...I was thinking of doing the exact opposite in my system. I've seen a good number of audiophiles swap in and out power cords...and even some add IEC sockets to the component so they can swap power cords in and out. But man...I just keep thinking that the weak link will now be the socket. I'd much rather prefer hardwiring.

have fun!

E-Stat
07-06-2004, 12:13 PM
And of course we have the requisite question: how do you think six-feet of powercord will undo any gremlins unleashed by the powerplant itself, line transformers and un-shielded service feeds that supply your mains? Think about it.

You've got it bass ackwards. It is the first six feet, not the last. The interference is caused by computers, appliances, and a range of other digital devices found in the home that you filter out.

rw

skeptic
07-06-2004, 02:55 PM
You'll need to use a chassis punch to cut a clean hole of the right size and shape. You have to drill a pilot hole first. If you know someone with such a tool borrow it. It will make a nice clean cut. File off any sharp edges or any small pieces of sheet metal not cleanly removed with a rat tail file. You may also be able to use a hole saw drill bit to make the hole. Try Hubbell for an IEC chassis mount male plug socket to mate the female connector on the IEC power cord. Any good electrical supply house should carry them and several other brands. There is probably hardware available in some high end audio retailr store especially if they do repairs on site although their prices will undoubtedly be much higher. Choose a spot in the amplifier where there is plenty of clearance inside. This can be difficult or impossible depending on how tight it is in your amplifier. If you can get a socket where there are no live exposed parts that will fit in your amplifier, that would be best. If this is impractical because the internal layout is too tight, try to find a socket that will surface mount on the outside back of the chassis. Drill a large enough hole for a rubber gromment or bushing to protect the wire from being abraided and still let the cord through to the inside. If the socket requires being secured with sheet metal screws or machine screws and nuts, be sure you pick a spot with available clearance for that too. Again, try to be very careful to be certain that there are no live exposed parts, no stray strands of wire, and no short circuits to the chassis at either end. you may have to remove and replace the existing leads to the on/off switch and transformer primary because they are too short to reach the new socket. At that end, you will probably have to solder new leads on and at the other, you will solder or screw the leads to the socket depending on what it requires. Try to route the power cord away from any signal wires. If there are exposed live parts, you may want to insulate them. Plastic electrical tape is fair but not great. Wrap the exposed parts several times to be sure they are insulated. Heat shrink tubing is much better. Since most people don't have a heat gun, a high powered blow dryer will do just fine for shrinking it. If you use heat shrink, try to attach the wires to the socket before you install it in the amplifier. This way you will avoid accidentally heating and damaging other electronic components.

Personally I do not recommend that you do this. I don't think it will improve your equipment performance but many people are determined to experiment even thought they will learn an expensvie lesson. Also, be aware that you are voiding any manufacturer's warranty and probably the UL listing of the equipment. You assume full responsibility for any consequences. This is not like experimenting with speaker wire or interconnects. If you don't know what you are doing, are not handy with tools, or just plain careless, you have the possibility of severely injuring or killing yourself or someone else. If you are not familiar with working with hand tools and small electrical appliances, get help from someone who is or at least have someone check your work before you plug it into a wall outlet. You can also check your own work with an ohmmeter, continuity checker, or multimeter. both power and neutral leads should be open to the chassis ground. They should show continuity with each other when the power on/off switch is on and open when it is off. If there is a ground pin, it should show continuity to the chassis and open to both the hot and neutral legs always. As a final check, be sure there are no stray pieces of wire, solder or other foreign debris inside your amplifier. Turn it upside down and shake out anything loose before you put the cover back on. Good Luck.

mtrycraft
07-06-2004, 08:58 PM
You've got it bass ackwards. It is the first six feet, not the last. The interference is caused by computers, appliances, and a range of other digital devices found in the home that you filter out.

rw


With the power cord? Are you serious? Didn't think so.

E-Stat
07-07-2004, 05:20 AM
With the power cord?
Brush up on UL / EN 60950 RFI standards. The Europeans take this more seriously. Don't worry about noticing such things with your boombox.

rw

skeptic
07-07-2004, 08:08 AM
If the Europeans take a technical issue seriously, you can be sure it is worthless. I lived in Europe, specifically the southwest of France for nearly two years. The power distribution system there stinks. Like everything else I saw, it was designed and built on the cheap. They transmit at 230 volts because they can use lighter gage wire to transmit a given amount of power. The price is that if you get a shock, you have a much better chance of dying. Every time there was an electrical storm, power went out with every lightening strke. My French made Thompson television set failed several times in electrical storms. Once a capacitor across the AC line input exploded. Another, a fuse for the flyback transformer popped. Each time, a technician fixed it under warranty. He had special parts to jury rig a quick fix and knew exactly what had happened having fixed the same problem on these sets again and again. My friend was nearly burned to death with a defective electric blanket. He returned it to the department store (Nouvelle Galleries) which sent it back to the factory. After about 6 months, the factory said they had determined that it had been used improperly as they had decided that it must have been folded. No appology, no refund, not credit, no nothing. In Britain, if you buy an electrical applaince it comes without a plug. You have to buy your own and it's always the same one. It's designed for an appliance which can draw up to three kilowatts. And that's the one you use even if the appliance is a two watt alarm clock. Somebody from Britain, please say it ain't so. At least not anymore.

Do you know what IEC is about? After the second world war, American engineers working in Atlanta set up cheapo standards to be used in Europe. They needed a uniform standard to built equipment to, could not afford to build to American standards, and the risk of successful lawsuits with big payouts to victims of defective items was non existant. That's how they got it. Now some Americans want it too. Anything to save a buck. At an industrial level, I instinctively hate it because equipment built to that standard is invariably flimsy compared to what I am used to. As a consumer, I don't like it any better.

By the Way, the FCC sets standards for RF emissions from all electrical appliances sold in the US. Just look at the back or inside of any remote control or any cordless telephone or the beginning of any operations manual for an appliance. Certificaton of compliance will be there.

E-Stat
07-07-2004, 08:44 AM
...specifically the southwest of France for nearly two years. The power distribution system there stinks. Like everything else I saw, it was designed and built on the cheap.
I have no reason at all to defend the French!



In Britain, if you buy an electrical applaince it comes without a plug. You have to buy your own and it's always the same one. It's designed for an appliance which can draw up to three kilowatts. And that's the one you use even if the appliance is a two watt alarm clock. Somebody from Britain, please say it ain't so. At least not anymore.
While I'm not from Britain, the wife did purchase a hair dryer last year in Scotland and it comes with its own molded plug with built in fuse.


(regarding IEC plugs) As a consumer, I don't like it any better.
To each his own. I always prefer choices to not having them.


By the Way, the FCC sets standards for RF emissions from all electrical appliances sold in the US. Just look at the back or inside of any remote control or any cordless telephone or the beginning of any operations manual for an appliance. Certificaton of compliance will be there.
Setting a standard and assuring it fully works are separate matters. Here's the standard disclaimer found immediately following that FCC Class B note:

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
-Reorient or relocate the receiving attenna.
-Increase the separation between the equipment and receiver.
-Connect the equipment into an outlet on a circuit diffferent from that to which the receiver is connected.

Disclaimers are there for a good reason.

rw

skeptic
07-07-2004, 08:56 AM
"While I'm not from Britain, the wife did purchase a hair dryer last year in Scotland and it comes with its own molded plug with built in fuse."

At last, progress. What about England?

The inevitability of RF noise given modern technology is a simple fact of life. We could spend a fortune trying to prevent it from ever being a problem instead of being a problem in rare cases. It wouldn't be worth it. I've built several shielded rooms which were also acoustically dead rooms to measure rf and sound emissions from various equipment to assure complaince to FCC rules. The result is that most of the time, the source is very localized and easy to isolate. Just be glad we live in an age of cable TV and not back in the era which every other guy built a ham radio transmitter and all TV was recieved on an antenna. One of the happiest days I can remember was when a hurricaine blew down a huge transmitting tower one of my neighbors had erected across the street. We never got interference from it again. The only real source of RF trouble I can remember was from WTFM whose transmitter was 6 blocks away. No FCC rules short of shutting them down would solve that. Wait a minute, maybe when they went from horizontal polarization to vertical polarization it got better. I don't remember it was so long ago.

Resident Loser
07-07-2004, 09:08 AM
...did you catch the bass or did the bass catch you?

First...last...who mentioned a pecking order? Not me!

But let's not get into an argument over semantics...let's get into one re: your misconception.

I take it you never did much troubleshooting...I have... 35yrs. worth...you have to know which end is up, so...since you mentioned it, the power cord IS the last six feet(or so) in the AC mains chain...the powerplant is the source and that expensive mamba snake merely an extension of it...go ahead, prove it to yourself...take a VOM and see if you don't have 110v or so at the IEC connector...does the amp(or other device) inject anything into the grid? NO, it surely doesn't, actually it's vice-versa. Therefore, logic dictates it is the LAST thing in the supply line before the AC gets to the device's power supply board. On second thought don't...I'd hate to be responsible for your getting shocked...I'm not completly comfortable with your level of expertise in such matters...

I'd take a guess you might not subscribe to the practice of choosing loudspeakers first and everything else afterwards...another error IMO...

Since I always like to be somewhat familiar with what I speak about, I took the time to peruse that UL/EN 60950 standard...on the face of it, it seems to be simply an upgrade of the previous 950 spec...dealing with safety issues, mechanical and electrical stresses and the like, with regard to computers, computing devices and telecom interfaces...not RFI/EMI issues with after-market powercords...in fact, doing a Google with the RFI-suffix shows only those safety standards as applied to the manufacture of lower voltage(-80vdc)switching supplies and nothing to do with their culpability in the whole RFI matter(although the standards-adherent manufacturers do claim low RFI/EMI levels, but that is a separate issue)...again, it was only a cursory search, so perhaps another one of those factoid acorns, from whence great oak tree myths blossom, may have escaped me.

The Europeans also instigated the ISO standards...a commonality for the economic union, again like the ubiquitous IEC-type connector, strictly an economic issue. ISO provides bragging rights and ensures that the procedures to be followed are easily accessible to anyone who needs them...the Bell System Practices did the same thing 80 or so years ago...no big whoop, nothing new under the sun...Judge Greene be damned...but I digress.

jimHJJ(...and this cord clears up digital hash how?...)

E-Stat
07-07-2004, 09:55 AM
At last, progress. What about England?
Can't say as we spent ten days in Scotland. Does not being part of the UK count?



I've built several shielded rooms which were also acoustically dead rooms to measure rf and sound emissions from various equipment to assure complaince to FCC rules.
The most impressive RF shielding I've seen was at the Equifax data center here in Atlanta. An elder in my church used to be the data director and I got a tour of the facility a couple of years back. The communications server (a Prime minicomputer) was capable of serving something like 5000 simultaneous requests. The incoming circuits were housed in a relatively small room, say 10 x 10 that was completely insulated in copper. You were essentially walking in a giant copper box. They took isolation kinda seriously. :)



The result is that most of the time, the source is very localized and easy to isolate.
Bingo! Hence one of the compelling reasons behind the use of aftermarket cords that offer RF shielding. Prevent RF generated by digital audio components (or other nasty sources like computers) from directly infiltrating the AC line. I use one specifically designed for the task with my CDP and a really nice shielded Belden one with my turntable. Additionally, I run the turntable cord through a Monster conditioner to reduce overall noise otherwise found in a high gain MC environment. The result is that with the arm cued and gain set to fully drive amps, I get zero noise with ear placed on speaker.

rw

E-Stat
07-07-2004, 10:43 AM
...does the amp(or other device) inject anything into the grid?
Of course. RFI generated by many household electronic devices (primarily digital) can be "injected" into the house mains. I'm not concerned with cleaning up what gets to my house as much as what's in my house.


I'd take a guess you might not subscribe to the practice of choosing loudspeakers first and everything else afterwards...another error IMO...
You are mistaken as to my priorities.

<a href="http://forums.audioreview.com/showpost.php?p=40466&postcount=92">Here's one</a href">
<a href="http://forums.audioreview.com/showpost.php?p=20243&postcount=14">Here's another</a href">



...not RFI/EMI issues with after-market powercords...in fact, doing a Google with the RFI-suffix shows only those safety standards as applied to the manufacture of lower voltage(-80vdc)switching supplies and nothing to do with their culpability in the whole RFI matter(although the standards-adherent manufacturers do claim low RFI/EMI levels, but that is a separate issue
Mea culpa. Try IEC801-4. Here's but one European manufactured cord specifically designed for this purpose:

<a href="http://www.eupen.com/cable/emc/emc02.html">Eupen GNLM</a href">


......and this cord clears up digital hash how?...)
Read the provided link. There are two separate strategies.

rw

Jurgenvanes
07-07-2004, 11:39 AM
Hi,

Initially I got the idea of modifying the powercords out of curiosity and I thought I experiment with it. As I read here, it isnít an easy job to pull and I seriously doubt if I should continue. Iíve read and heard a lot about the influence a powercord has or hasnít got. The modification to the backpanels of my amps doesnít seem so difficult to make, so I thought experimenting was the answer to the question.
As space is limited in my dorm my computer is in the same rack as my stereo components and my powercords run down about 3 inch (10 cm) behind the back of my screen. My screen starts to flicker a little as soon as I switch on my amps, so there is some interference visible. Between what? I donít exactly know and that is why I thought experimenting was worth a try. The new socket becoming the weak link if I remove the standard powercord sounds logical to me.

As to all the technical information and about all the different standards, I can only say that here in the Netherlands we use 220v and that if you get a shock you have a chance of dying, but the electrical systems are well protected here and you almost want to do on purpose to get a shock. I also canít speak for the power distribution in France or everywhere else on this planet besides here in the Netherlands. The power distribution can handle severe electrical storms and the network of powerplants is designed that in case a plant falls out the other powerplants can take over without you even noticing it. We designed our power distribution with the same care as we protect ourselves against the influences of the sea. Very solid!
Here in the Netherlands everything, except for an amount of audio products, comes with hardwired powercords and plugs with an ISO standard.

I think I will let my curiosity be for what it is; I donít want to be the one who gets an electrical shock by putting my fingers into something electrical and trying to modify something, which at first site looked simple.

I might go for plan B: an isolation platform under my components, maybe this prevents my screen from flickering.

Cheers!

E-Stat
07-07-2004, 12:05 PM
... my powercords run down about 3 inch (10 cm) behind the back of my screen. My screen starts to flicker a little as soon as I switch on my amps, so there is some interference visible.
I would start by isolating signal wires, be they for a computer monitor or audio interconnects, from the power cords. You might try using plastic conduits to separate the two. Also, you might want to experiment with your component placement. Power amplfiiers with their larger power supplies need more space between them and sensitive electronics. If practical, put them on top of other components rather than the other way around. Although I generally do not recommend power conditioning devices for use with receivers, amps, and the like, your environment may benefit from them.


I might go for plan B: an isolation platform under my components, maybe this prevents my screen from flickering.
While I believe there can be audible benefits from mechanical isolation devices, I doubt they would help with your screen flicker.

rw

skeptic
07-07-2004, 04:24 PM
"My screen starts to flicker a little as soon as I switch on my amps, so there is some interference visible."

If the effect is not transient (doesn't go away after a few seconds) the most likely cause is the magnetic field created by the power transformer in your amplifier. Try to move the power amplifier away from the screen by at least several feet. I have purchased custom manufactured shields for this problem for computer monitors. The shields were very expensive, about $1000 each and made from MU metal. In that case it was overhead power lines. You cannot isolate the power amplifier from a CRT with a simple shield, you need a fairly complete enclosure (except for the screen of course) and heat dissipation is a problem.

"here in the Netherlands we use 220v and that if you get a shock you have a chance of dying, but the electrical systems are well protected here and you almost want to do on purpose to get a shock. "

Only a fool tempts fate. Most protection of electrical systems is to protect equipment not people. But even if you have GFCI on every circuit sooner or later someone will die when the GFCI or whatever other protection you use fails. Be smart, avoid a shock at all costs. Even a shock expected to be less than fatal can have serious consequences for your future health. Don't make a game out of it, you will almost certainly lose.

Resident Loser
07-08-2004, 07:37 AM
...took a look at over 500 entries that mentioned IEC 801-4, not a one was audio related...there were testing organizations, parameters for the spec itself, data processing equipment mfrs. that adhere to the spec, various supporting PDFs, medical equipment, that sort of thing...

And a source for this definition:

IEC 801/4 is the international standard equivalent to ANSI/IEEE 62.41-1980. Five levels 0f severity are defined in this spec depending on the environment at which the product is used as defined below:

Level 1: Well-protected, i.e. a computer room;
Level2: Protected, i.e., control room of an industrial plant;
Level 3: Typical industrial, i.e. area of industrial process equipment;
Severe Industrial, i.e. outdoor area of industrial process equipment.
Special situations to be analyzed by IEC.

Kindly take notice, your listening room is not referred to therein...basically industrial concerns where such interference can cost $$$ and in some cases, i.e. life support, lives.

Additionally, there is this white paper authored by Douglas C. Smith, formerly of AT&T Bell Labs, entitled "An investigation into the Performance of the IEC1000-4-4 Capacative Clamp"

Please note the IEC 801-4 is now part of a new IEC spec. The abstract states in part: "...Data presented shows that the test may be too severe and contains repeatability problems that causes excessive cost to be added to the designs. In addition, a common mistake in application of the test is shown to double the stress on the equipment being tested."

The spec would seem to be applied specifically to data I/O wiring, UPS, other power supplies, network interfaces, servers and medical/medical test equipment. It also deals with EFTs(not RFI) that are in the region of .25kv-4kv and at freqs up to 100kHz.

Even with units that comply with the spec, it is advised by some they be contained in a suitable steel enclosures for optimum effectiveness.

Bottom line is that it too seems to be more of an economic constraint of sorts. In order to get a "CE" rating products must comply to the IEC spec. Neither the FCC nor Industry Canada currently have this requirement, although many non-European mfrs. find themselves required to follow it in order to sell their wares on the continent.

So while it may be like wearing suspenders and a belt I suppose it couldn't hurt, but as an added expense, it would appear to be not really necessary in an audio application.

jimHJJ(...another factoid?...)

E-Stat
07-08-2004, 07:58 AM
...took a look at over 500 entries that mentioned IEC 801-4, not a one was audio related...
You're missing the forest for all the trees. Here are some quotes from Eupen regarding the linked cable:

"This construction makes the EMC/CORD to be an electrical network of passive components, providing common and differential mode attenuation. The EMC/CORD performs well over a wide frequency band, especially against "burst" impulses according to IEC 801-4. It is an interesting tool to control conducted RF interferences into and out of equipments, thus helping the designer to meet EMC regulations...

Mains connection of electronic equipment, such as:
* data processing equipment
* audio devices
* measuring equipment
* medical devices"



... it would appear to be not really necessary in an audio application.
Speculation based opinion noted. Which happens to differ from the direct experience of a number of respected manufacturers of audio components (who don't market cords) with whom I've spoken. Not to mention my own experience. Everything is relative. Your resolution threshold is lower than others.

rw

skeptic
07-08-2004, 08:34 AM
"an electrical network of passive components, providing common and differential mode attenuation. The EMC/CORD performs well over a wide frequency band, especially against "burst" impulses according to IEC 801-4."

How much attenuation and at what frequencies? 0.5 db at 20 mhz? Qualitative statements mean nothing. Where are the specifications?

A couple of small capacitors and inductors can do the same at a small fraction of the price.

A real power conditioner has at the very least an isolation tranformer. But for the kind of power protection industry relies on to protect its most valuable electrical equipment which is it's mainframe computers and communicatons network from damage, failure, or corruption, they rely exclusively on UPSs. (Sometimes with backup generators.) To an engineer, a cheapo consumer "power conditioner" with a handful of overpriced hospital grade receptacles, a couple of capacitors, and inductor or two and an MOV surge protector is usually an overpriced ripoff and a power cord is a joke.

Buyer Beware. The wolves are everywhere.

E-Stat
07-08-2004, 08:46 AM
How much attenuation and at what frequencies? 0.5 db at 20 mhz? Qualitative statements mean nothing. Where are the specifications?
When all else fails, read the instructions. See "Eupen GNLM" link in my post above. You will find that one of their strategies is as you suggested.

rw

gonefishin
07-08-2004, 09:44 AM
To an engineer, a cheapo consumer "power conditioner" with a handful of overpriced hospital grade receptacles


Hospital grade outlets in the right application can have a dramatic effect. But, if you can survive without the "green dot" (which I'm sure most of us would be able to) we could get similar build quality in industrial grade outlets. These outlets are actually held to many of the same tests as hospital grade outlets. Except hospital grade outlets go on to earn their "green dot".

Green dot electronics isn't limited to cords or outlets tho. You can have green dot fixtures, green dot motors, green dot portable 2way radios among many other things. Although there is one interesting thing to note about green dot. If a green dot device is plugged into a green dot outlet, all is good...but if you simply plug in any device to a green dot outlet...the results could be less than satisfactory.

This is all assuming that your using the correct application, of course


dan

skeptic
07-08-2004, 10:46 AM
"Hospital grade outlets in the right application can have a dramatic effect."

Yes, in a hospital as they were intended, the extended ground connection sleeve which makes contact BEFORE the neutral or phase wire might prevent a static spark from igniting a fire in any place where oxygen is in use, especially if there are volitale chemicals around. On the other hand, for connecting an audio system, they have no advantages over any ordinary UL approved 5352 let alone a 5362. The resistance between the plug and the socket is so infinitesmal, it cannot be measured with anything but the most sensitive equipment. I'd be surprised if it is typically over 1/1000 ohm.

skeptic
07-08-2004, 10:59 AM
RF can "infiltrate" which I assume means be induced in overhead power lines which are NOT shielded and in the Romex wiring thoughout your house which is NOT shielded. Once it's there, a shielded 3 foot length of power cord is not going to get it out or filter it. That is the job of a power supply and if that can't do the job because the equipment is so junky, a power conditioner. Usually, RF problems in a sound system is the result of directly being induced into the preamplifier high gain stages and the high gain input cables such as microphone and magnetic phonograph cartridge connections. That's where extra shielding can and does make a big difference. How fortunate that it is so cheap and easy to do yourself. I always run a bare thin copper wire along my phono leads and cover the bundle in aluminum foil. I ground the wire to the preamp chasis along with the turntable ground. It works perfectly.

If you are foolish enough go to the trouble and expense of buying shielded power cords, be sure that they are UL listed. Shielding a power cord can be dangerous in more ways than one. The shield will decrease the wire's ability to dissipate heat. This could spell trouble especially in large power amplifiers which have a heavy draw. Decreasing the heat dissipating capabilities of wire reduces is ampacity and therefore the current necessary to cause it to catch fire. If that is below the 15 or 20 amp circuit breaker protection, the quality of your sound could become the last thing on your mind.

Resident Loser
07-08-2004, 11:10 AM
...and they seem a very minor minority...It's been said before, no on else seems to be touting adherence to the spec with re: to an audio application...that's what my web search revealed and that is what I have passed on. The spec itself and the testing procedures involved are concerned with stopping or lowering EFT induced failures of PC and computer driven hardware.

Here is some further info:

801-2 covers electrostatic discharge
801-3 covers with radiated frequencies(RFI)
801-4 covers EFT(Electrical Fast Transients)at voltages and frquequencies previously mentioned, in the timeframe of nano-second bursts
801-5 covers voltage surges
801-6 covers conducted(as opposed to radiated)RFI

They(Eupen) can say "such as" audio devices all they care to, no harm, no foul...other than the fact as it might seem to reduce their credibility to some...they could also suggest it might aid in preparing a righteous PB&J sandwich...prima facie evidence indicates that the spec is not written with either application in mind...the IEC does not stipulate such use. This is quite clear once you are willing to accept the realities as indicated by what I see as overwhelming evidence.

As I have previously stated re: eutectic solders, hospital-grade connectors, IEC line cords and other items, the manufacturers do not espouse the uses that the "audiophile-types" do...but of course, the "golden ears" know better...

jimHJJ(...and BTW, my "resolution" is quite fine...)

As an addendum I just did a google on "IEC 801-4 compliant power cords"...checked 15 pages...again, ZERO audio apps...not even Eupen...

jimHJJ(...again..)

E-Stat
07-08-2004, 12:07 PM
If you are foolish enough go to the trouble and expense of buying shielded power cords, be sure that they are UL listed. Shielding a power cord can be dangerous in more ways than one. The shield will decrease the wire's ability to dissipate heat. This could spell trouble especially in large power amplifiers which have a heavy draw. Decreasing the heat dissipating capabilities of wire reduces is ampacity and therefore the current necessary to cause it to catch fire. If that is below the 15 or 20 amp circuit breaker protection, the quality of your sound could become the last thing on your mind.
News flash: there are actually companies out there with engineers who understand these things. My aftermarket cables are all UL listed. The heavy gauge cord for my 10 amp power amps is not shielded.

rw

skeptic
07-08-2004, 12:10 PM
Here's a real life reference. In 1984 to 1986, I installed backbones for two large lans in a software development center. One was a Micom asynchronous network tied into a local Unix data center and the other was a sychronous IBM network which linked at one end to a remote IBM data center through a fiber optic about 2 miles long. The runs were 25 twisted pairs of telephone wire for the micom network and RG 62 coax for the IBM network. There were about 300 runs of coax and about 50 runs of synchronous. They were from 1100 to 1300 feet long from the PDF (primary data facility) to the modems in the data closets in an 11 story high rise. They served about 1000 users or more at a time with a theoretical maximum capacity of about 100,000 users. They sat in open aluminum ladder type cable trays. The voltage was about 1v peak to peak and there was no error correction. Shortly after it was completed, someone else against my instructions dumped about 50 BX cables (used for a fire alarm system) and 25 to 50 unshielded 70 volt PA speaker lines in the tray along almost its entire length. The cable tray also ran past a 13,800/480 volt substation with two 1500 KVA transformers and a 480/208 volt substation with two 1000 kva transformers. Because of concerns about the interference this might cause, the system with its problems was mathematically modeled and the results showed that there should be no problem. And eperience bore it out as no complaint was ever traced to a problem with this cable installation. Now what were you saying about your audio system?

E-Stat
07-08-2004, 01:19 PM
Here's a real life reference... And eperience bore it out as no complaint was ever traced to a problem with this cable installation.
I guess this is where I should be impressed. Congratulations, I hereby award you this gold star: <img src="http://home.comcast.net/~ralphwallace/images/audio/star2.gif">



Now what were you saying about your audio system?
That which is relevant to audible differences in high performance audio systems backed by engineers who actually work in this field

rw

skeptic
07-08-2004, 01:42 PM
Congratulations E-stat, who do you work for and when did they hire you?

E-Stat
07-08-2004, 01:51 PM
Congratulations E-stat, who do you work for and when did they hire you?
Aperum - March 31, 1992

rw

skeptic
07-08-2004, 03:37 PM
What kind of audio equipment do they make? Which ones did you design?

E-Stat
07-08-2004, 03:57 PM
What kind of audio equipment do they make? Which ones did you design?
Absolutely none. Aperum is the leading developer of midrange distribution software and I remain a software engineer. Evidently, I need to jog your memory as I have already provided this information to you before:

<a href="http://forums.audioreview.com/showpost.php?p=32154&postcount=139">One</a href">
<a href="http://forums.audioreview.com/showpost.php?p=30390&postcount=139">Two</a href">

rw

skeptic
07-08-2004, 04:02 PM
Amazing as it may seem, I do not read all of your gems. And I may occasionally forget those that I do. My loss. Maybe it's Alzheimers or a senior moment.

Sorry, I must have gotten carried away. You made your point so authoritatively, I got you mixed up with John Curl. I thought you designed audio equipment for a living.

E-Stat
07-08-2004, 04:33 PM
You made your point so authoritatively...
Why thank you.

Other than having a life-long love of music, I have simply enjoyed the dumb luck of befriending three audio reviewers over a thirty year span and the experience over time that has unfolded. Through those contacts, I have been introduced to a number of prominent engineers of very high performance audio components (not to mention classical music when I was 18). You might find having a discussion with Luke Manley of VTL quite instructive. Although a soft spoken and quite modest man, his Siegfried amps are sonic jewels. Harry Pearson, founder of The Absolute Sound, has always had access to a wide range of incredible components. Visiting HP with his veritable playground of several systems worth half a million or so is always a treat. His spectacular primary review system (circa May '04) is a wonderful tool for evaluating the quality of musical recordings. He gets test pressings from many sources, including Telarc, Reference Recordings, Classic Records etc and has had most of their producers to his house to sample their wares in a rare environment. You will appreciate the fact that he listens largely to classical music and makes it a point to regularly attend Carnegie Hall. On that system, questions of "does zip cord sound as good as Valhalla" or "can you hear differences among CD players" are rendered comical.

rw

Resident Loser
07-09-2004, 04:05 AM
...sneaky sumnab!tch, can't you...

jimHJJ(...LOL...)

skeptic
07-09-2004, 10:21 AM
Yup!
Ain't I a stinker?