Modifying powercords

[skeptic]

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]

...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]

"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.

[E-Stat]

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

[skeptic]

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.

[E-Stat]

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