I started building my own power cords using Venhaus shielded twisted pair 12 gauge wires. I then used their Flavor 3 design.

If you'd like to see visually how much energy is transmitted outside of a power cord, just get your self a Greenlee Non-Contact Voltage Detector(I believe that's the name). It is a small, battery powered probe that detect AC voltages starting at around 60 volts AC. When it detects one, the led lights up and it emits a high pitch tone. When I use the Flavor 3 cords, there is no detected voltages, though I can pick up a voltage within a few inches of an unshielded power cord. So, whatever devices I have that use a detachable power cord, I've replaced with the Flavor 3 variety. The only complaint I have is that the Venhaus cables are pretty stiff. I don't go overboard on the high dollar plug ends.

I've built my own as well, using the DH Labs bulk AC cable and connectors from Wattgate and Marinco.

Opinions on whether they make a difference or not has been documented on these boards before and varies widely.

That's about as much as I want to say at the moment, as I'm not up for doning my asbestos suit today for the ensuing flames.

Interesting analysis. I can see where having well-shielded power cables can be a benefit, thinking mainly about all the other cables that are typically in proximity to those cables and may not appreciate the "bad influence" of an unshielded power cord.

Soundhound\'s DIY Interconnects

The radiated AC voltage from a power cord is not going to have any effect on the internals of a piece of equipment unless that equipment is very poorly designed. In sensitive circuits, that's the reason for outboard power supplies.

Just being able to detect the radiated electromagnetic field of AC verses not being able to means nothing. If you can tell me exactly which circuits would be effected and the technical means of the effect, I'd like to hear about it.

Flame On
I'm just providing input on what I have tried. I gave the results I could test for. Those who want to comment against my results need to provide proof on their own.
Flame Off

Being a designer of audio equipment, I try to debunk misinformation, and unfortunately the audio field has more of it than other fields.

The EMF around a power cord is not going to have any sonic impact on a properly designed piece of equipment. If somebody is concerned with the EMF being picked up by interconnects, I need to remind them that good interconnects already have shielding which protects them from interference. In any event, it is good practice to keep AC power and low level audio cabling at least a foot or so apart, and never have them running in parallel for any distance in order to eliminate inducted interference (this is standard installation practice in professional installations, and it should be followed in the home).

If someone is concerned about EMI/RFI being radiated from a power cord, this is what power line filters are for - use them! They are inexpensive and effective if this type of interference is a problem. Tripplite "Isobar" series filters are extremely good at stopping EMI/RFI from reaching equipment, and stopping digital clocking artifacts or switching PSU noise from one piece of equipment from entering another.

Once the AC is inside the equipment, in a good design, it is kept far away from low level circuits, and proper shielding is incorporated. The path of the 120VAC is short; generally it goes through a fuse, a "hard" on-off switch, a surge limiter (in power amplifiers), then to the power transformer - all of this is far away from sensitive circuits.

So whatever is used for the short transmission of AC from the outlet to the IEC plug on the back of your gear is not going to have an impact, and whether or not the EMF is escaping from the jacket of the cable or not has no bearing on anything.

This is not flaming - I'm just passing on solid engineering practice, which has been proven over decades of use within the audio industry.

If your concerned about EMF from a power cord, then what about the EMF coming from the rest of the wiring in the house?

Not to mention the electromagnetic field generated by the power transformers in the equipment. And of course, what about the EMF coming from overhead high voltage power lines in the vicinity. There are much, much, much more important fish to fry than worrying about EMF escaping from an AC cord.

Two things to say.

1. I use B&W CDM7NTs as my mains. I originally got them for a 2-channel audio system. I noticed a distinct difference when I replaced standard 2-wire copper cable with a pair of DH Labs Q-10 cables that were biwired. The DH Labs cable is relatively inexpensive, and you can buy cables used for about 1/2 the original price if you look on Audiogon or eBay. When I got my 1070 and a CDM Cnt I made up a third cable from DH Labs Q-10. I use 12-guage copper for the surrounds, and don't plan to change that unless I win the lottery.

2. I added an external phono stage to my audio system several years ago. First I tried a Creek model, but there was a lot of noise from FM radio signals, so I sent it back. I then found a Gram Amp 2 and it had less noise. At the suggestion of Graham Slee, the designer, I got a bunch of ferrite shields for the turntable's power cord and the interconnects running from the turntable to the phono stage and from the phono stage to the Amp. That fixed the problem and it was cheap.