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Blue Snake:

Do-It-Yourself Power Cable

last updated December 14, 2001

Blue Snake Power Cord

This is my second diy power cable project. For a general description of the building process of a power cable you are referred to the Conradsel project. I’m not going to repeat all that since I rather put a large picture of the Blue Snake on this page J Therefore on this page contains only the main differences in building the blue snake.

Why the Blue Snake?

The idea for the blue snake came up after I had very good experience with using standard 3*1.5mm rubber power-cords. This rubber cord has been connected to my hifi for at least two months and I was happy with the results.

Only a short time ago it was replace by the ‘Conraadsel’ cable based on 5*1.5mm screened cable I buy at Conrad.

The main advantage o the Conradsel cable was it’s metal screen, which would prevent HF from outside to influence the cable and would also prevent the cable to impose a 50Hz humm on other audio cables (interlinks and speaker cabling) close by. However, rubber is a much more preferable dielectric as PVC and therefore one would like to combine the best of both designs.

Looking at both types of cable I had the idea of building the Blue Snake: By using standard available rubber cable of high-quality and adding a screen to this cable I would at least have a high-quality power cord with shield. However, for safety reasons I needed to protect the shield and other cable parts. After all, 220Volt can get you killed.

On the right you will find a picture of one of the parents of the Blue Snake . The family resemblance is striking isn’t it? Finally, by choosing a nice finishing sleeve our power-cord would not only sound interesting but have good looks as well. There are a few limitations to the Blue Snake, but I will come back on that later in the article.

What do you need?

· 1.0 meter (1.5 or 2.0 meters may also be possible) of rubber cable with 3 * 1.5mm leads. The product code for this cable is HR05RR-F, this cable is available almost everywhere.

· Heavy Coax cable such as the RG213 which we will use or it’s metal shield. Take 1.5 times the length o the rubber cable. (Hfl 3.75/meter)

· A high-quality mains plug made out of rubber. Kopp makes nice ones (ca. Hfl 6,95) available everywhere.

· An IEC pug for the hifi component side of the cable. Take one with a round cable entry and take one that accepts cable with a larger diameter (Hfl 4.95/piece).

· Crimp Sleeve in a nice blue color. I use 10mm think and it is available for Hfl 7.25/length (about 1.20 meters) This is were you have to pay attention: The length of the sleeve more o less determines the length of the blue snake. If you need/want longer lengths than 1.20 meter you will have to overlap on or more times (give the snake scrubs).

· A heavy heater in order to crimp the sleeve.

· The obvious thins like a knife, screwdriver, soldering iron etc.

The total costs for building a Blue Snake are close to Hfl 30,-- ($12.50) for a 1-meter power cord.

Building the Blue Snake

Take the coax and cut the jacket over the full length. Be careful, directly under the jacket is the metal shielding that we use and this must not be damaged. After the jacket is removed, the metal shield can be removed from the rest of the coax.

Now take the rubber cable and while compressing the shield a little it becomes wider and can be placed over the rubber cable. Once the shield is completely over the rubber cable, fixate it on one end with a piece of tape and stretch the shield to the other site of the cable. Excessive shield should be removed such that you end up with a cable where the shield is really tight over the rubber cable.

Now take the crimp sleeve and put it carefully over the cable. Once everything is in place, crimp the combination with a heater. Now mount the mains plug and the IEC power connector and you’re done. Please note that unlike the Conradsel cable the rubber cable contains only 3 leads, so there is no need to take leads together with this cable.

My supplier only stocks crimp sleeve until a certain length, in this case 1.20 meters. As a result, I cannot build a longer version of the Blue Snake without having to use two overlapping pieces of crimp sleeve for a cable. Not the end of the world for me, but not desirable. There may be suppliers that have longer lengths of crimp sleeve in stock however (Rs-Components sells longer ones I believe) so that this may not be a problem in your case.

Also, should you want to use ferrite rings or so on the Blue Snake (to make it even more look like a snake) it is easy to hide overlapping pieces of sleeve under such rings. Everything is allowed (as long as you make it blue I think).

I was a few times on email why I would connect the metal screen on one side, the mains plug side, only. My rationale behind this is that should the power cord pick up any HF that these signals should be neutralized by connecting the screen to earth. By connecting on one side only, there will be no difference between the earth inside the cable and the earth outside the cable which may result in undesired behavior. Rather, by connecting the screen to earth on the mains side, any HF picked up is neutralized at the wall-outlet and will not travel trough the power cord anymore. The connected hifi component will therefore receive a “cleaner” earth.