Shielded Bottlehead Power Cord, With Pictures

[Grainger49]

I shrunk every picture to 70% in Photo Editor and they still spill over.  I don't know why.

My first power cord went well, not as good as I would have liked.  Notice I'm not posting the picture of it?

For my second power cord I decided to use the braided shield tubing I have.  Can't remember what it was for but I had it.

I twisted each pair and stuck them down at the end and waited for the twists to "set".

This is the clamp for all three pair of wires:

This is how the other end looked:

I used some heat shrink tubing I had to hold the braided shield in place then finished the IEC end.  In doing so I cut the white wires a little so there wasn't so much wire inside the IEC Jack.  I didn't get a picture of this but you get the idea.  I also soldered the wires together and really tightened the IEC connections down hard.  This is the finished IEC end:

At the plug end I soldered a wire to the braided shield and then slipped some heat shrink tubing over it.

I could have put the Tech-Flex on now to make it prettier, but forgot.  This shows the tubing to hold the shield in place and the end wires soldered together:

Test now or you are in deep fecal matter if you need to swapped wires.  If that is your situation you still can do it before you put the glue lined tubing on.

The finished product, a stubby Bottlehead power cord for my FP 2.

To be fair I used a stock power cord to do my first listening then the new power cord.  The results were much as the Eros, instruments separated, no confusion, the low bass had more kick, voices were clear and uncongested.

I had been using an aftermarket shielded power cord on the FP 2 and swapping that back in was a little of a step back.  I think it is similar to Bottlehead's Power Cord but more expensive.  I don't remember where I got it or the name.  It, too, is a short cord.

 

[randy@matrixq.com]

Grainger, you have taken power cords to a higher form of art.  The nice build pictures are quite inspiring and will be a nice help to a lot of people.  Thank you for sharing your project.

 

[Grainger49]

Randall,

Thanks!  There must be some secrets about shrinking the glue lined heat shrink tubing.  Both times it slid sideways on the AC plug and drooped on the IEC Jack.

There is also some secret to shrink the tubing and not melt the Tech-Flex.  I used low heat on my first, long, AC cord and I made a mess of the Tech-Flex at the shrink tubing.  Notice I didn't post a picture of it?

 

[sl-15]

Grainger, nice work! did you do a comparison yet between your first build bottlehead cord and the shielded one? curious if you think the shielding made a sonic difference. i have a power cord on my way too for my seducton. thanks, stefan.

 

[Grainger49]

Stefan, thanks!  And, no, I hadn't thought of that one.  I compared the Shielded Bottlehead to the stock and to the aftermarket I bought many years back (I'm pretty sure it is also shielded).  I'll give it a try tonight.  The Shielded is 1/2 of the length of the unshielded.  I wonder if it will be a fair comparison.

The first, unshielded, power cord went to the Eros, the next to the FP 2 and the final one will feed the P300.  The P300 is delivering <200W so at 117V that is less than 1.7A.  There is some real heat loss in the P300 so I will measure the current to the P300 to see if the cord is safe for feeding it.

Edit:  Yes, 1.7A is safe.

 

[randy@matrixq.com]

I've buggered up a lot of tech-flex myself.  I think it melts faster than the shrink shrinks.  Next time I do any of that, I might try shielding it with paper or something.

Your cords look good and I may try something like it this summer when I have some time off.

 

[Noskipallwd]

When shrinking tube near techflex or other easily melted material I use a little shield with my heat gun. I think you can buy them but I just made one out of sheet aluminum. Keeps the heat away from the techflex, I learned that lesson the hard way as well. Grainger, I had no idea you could charge your portable drill batteries by cooking them on the stove!

Cheers,
Shawn

 

[Grainger49]

Shawn,

My heat gun didn't come with the curved shields you mention.  I know exactly what you are talking about so I will get one.

As for charging, my cook top is radiant rather than inductive, inductive charges, doesn't it?  Mine doesn't charge just melts batteries.

 

[earwaxxer]

Grainger - Nice job with the power cord, and good pics to boot! Just goes to show, us DIY'ers can be happy and not spend the mega bux to get there. I havent really had a need for another power cord but I suppose I should build one to so I can cross that off my 'official audiophiledome membership' to-do list. Actually I could probably use it with my subwoofer amp. Food for thought. I will probably replace my 12" sub driver before that though. I dont think it (Pearless) is getting down to 20hz as much as it was advertised to. Probably replace it with a Dayton.

 

[Grainger49]

Eric,

Thanks!  I tried two different ways (MS Photo Editor and in Photobucket) to shrink the pictures to 70% of their size.  They keep displaying off the page for me. 

I would expect that a subwoofer amp would give the least, fewer octaves, effect of an improved power cord.  Maybe the Emotiva XPA-2, but I don't know what that component does.  Or the Squeeze box, is it fed from a wall wart?  Hard to say where you can fit one in.

 

[earwaxxer]

Yep - I have an MIT Z-cord on the Emotiva. I like that cord. Only payed $70 for it on ebay, and it definitely sounds better than your usual stock cord. On the Transporter I have a relatively big bucks JPS Labs digital power cord. That one also sounds better than stock, so I pretty much have left those alone. Quickie has battery - no issue there. My MSB Link Dac lll has its own proprietary cord with built in power supply, which leaves the Crown amp for the sub. Its a class D amp with built in power supply. That cord I could replace, but like you said, its prob. not a priority.

 

[Grainger49]

My Link DAC III used a wart power supply, well, wart in the middle of the power cord.  That whole power supply can be upgraded.  But that is a whole 'nother thread.

 

[earwaxxer]

Granger - You have the Link Dac lll as well! Interesting. MSB is an interesting company. It would be fun to own some of there high end stuff if it was affordable. I briefly compared the Link Dac to the Transporter and the later was more modern and 'sophisticated' sounding, although I do remember the Link Dac as sounding very nice, in an analog sort of way. Great bass, so I used it as a front end to my sub. Do you still have the Link Dac? How do you find the sound? sorry for the divergence off the thread topic, although I doubt there is much interest in talking about the Link Dac here!

 

[Grainger49]

Eric, you have a PM.

 

[ALEXZ]

Grainger,
Just curiosity : did you try to compare shield groundig at source with grounding at receiving side ?
It's could be interesting, especially if high gain stages (phono for example) is susceptible to RF noise.
Thanks,
Alex

 

[Grainger49]

Alex,

No, I followed the aftermarket one I already had.  I might try it with another power cord.

If the shield is grounded say at an Eros then the path to ground for any noise is through the shield, to the Eros chassis back through the power cord ground wire under the shield to the ground lug at the plug end.  It seems both circuitous and it ends shunting the noise into the power cord.  Where as if you ground the shield to the plug end ground lug it never gets into the conductors in the power cord.

Hmmmmm.... I'm going to have to think on this one.  

 

[ALEXZ]

Probably it is right way to ground at source.
Hovever, here is an alternative theory: star ground, where all grounded in one point on the chassis and from that point single wire goes to earth ground.  Well...  could be a pure fantasy, but I guess it's fun to try.

 

[Noskipallwd]

The cord I built for the Eros, I connected the shield to the source ground as I do with all the PCs I have built. The Eros is quiet, so at least I know it is not adding any noise. As to whether it helps remove noise, don't know.

Cheers,
Shawn

 

[Yoder]

did you try to compare shield groundig at source with grounding at receiving side ?

I have read in several different sources that you always want to ground at the source and never at the receiving end. There were some sound (no pun intended) rationalizations, but to be honest I just memorized the concept and not the science behind it.

 

[Grainger49]

Are we all saying that the wall is the source for the 120V AC, right?