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DIY DC power cables


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7 hours ago, Ralf11 said:

What is the inductance in the cable, and how does the AWG affect it?  Do you have a histogram or anything?

I don't have the test equipment with me to measure it right now (I have to wait until the lab is setup in the new house). I cannot find any simple equations for these things. Actual formulas for inductance of the different implementations turn out to be very complex, I could not find anything that wasn't several pages of arcane math.

 

The best I could do is the rough ratios between geometries assuming everything else is the same.

 

John S.

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2 hours ago, austinpop said:

 

John,

 

Now you have us really excited! Can't wait to try it.

 

Sorry, noob DIY question - from the pictures, it looks like there are 2 red and 2 white wires? And these are what connect together?

The 4S6 has a solid red, clear red, white and clear wires. The two red wires are connected together and the white and clear are connected together.

 

John S.

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6 hours ago, Em2016 said:

 

Hi John, will the DC plugs with screw-in terminals fit next to the USPCB, for both the USB REGEN and ISO REGEN?

 

Those DC plugs are quite large compared to a normal cable plug and may clash with the USPCB or even clash with the cheap hard adapter, side by side?

 

Cheers

Yes the DC plug with the screw terminals fits nicely on any of the REGENs with the USPCB.

 

You are going to have to bend the wire down very sharply if you want to avoid hitting the device the USPCB is plugged into. This is assuming you are using the USBCB on the upstream side of the REGEN (which is the side with the DC in jack. If the USPCB is on the downstream side (connected to the DAC) then there is no issue since the only thing on that endplate is the downstream USB jack.

 

John S.

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24 minutes ago, Forehaven said:

Does anyone know if there's a max. recommended length per DC cable?

There is no such thing, other really gross things like "a mile is probably too much". The longer the cable the more resistance and inductance you have, thus it is probably good to keep the cables aa short as possible.

 

Thus if you are using an LPS-1 you should have it close to the load.

 

John S.

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3 hours ago, sockpit said:

Slightly off topic but star quad related:

 

my speaker cables our diy, and made from 14 awg, four strand audio quest speaker cable design for in-wall installations.

 

when terminating them, I paired them together (since I'm not biwiring).  Problem is I didn't pair them diagonally.

 

now so far as I can see these four wires are not twisted at all, but just run parallel inside the casing. 

 

Would redoing the pairing so they are diagonally paired make any difference theoretically with speaker wires of this sort?

 

thanks.

Yes, the star quad configuration is NOT just about shielding, the big reason for using it in low impedance circuits such as DC cables and speakers is that the inductance is much lower with starquad.

 

So even if there is no twist, pairing diagonally opposite conductors will significantly reduce inductance of the cable. In most circumstances this will improve the sound through the speakers.

 

John S.

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Gold plating for power connectors is not necessarily a good thing. If the system is energized when you plug it in, a small spark is generated when they connect. This has enough energy to vaporize the gold plating where the

3 hours ago, R1200CL said:

I have found a Chinese manufacturer that may be willing to either offer these power cables we need using the suggested Canare cables. Free shipping.

 

It will either be a group-buy, or included in his product line. 

Length I'm not sure, but I think most is interested in short lengths. Maybe 20 cm. (0,65 ft). 

 

I expect a very nice price ?

Unless he as well has to use expensive plugs. 

 

I hopfully will know more later in a couple if days. 

Just make sure they know to connect diagonally opposite conductors. 

 

Thanks,

 

John S.

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7 hours ago, octaviars said:

 

This cable that goes along outside of the sheild will it matter how thick it is? My thougt is to hide a small wire under the blackmesh nylon braid so it is not visable and connect it to the sheild in the powerplugs. What is your thoughts on this @JohnSwenson

 

 

So far I have been using 24AWG wire for my tests and it has been working extremely well. As far as I can tell there are two issues: long length wire and very high frequency isolation. The 24 has worked well for the short cables I have built (up to 6ft), For really long ones you may need to go with thicker wire, but I have not done any experimentation on that so I really don't know for sure.

 

For isolating very high frequencies (say gigaHz stuff) the inductance of the wire is probably very important, so this tends to point to thicker wire, but there may be many issues at hand there, I would have to delve much further into that before I could make a recommendation.

 

John S.

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5 minutes ago, Michael-Elijah Audio said:

I didn't - I used the Response 4 wire speaker cable with an external expandable shield from here:

http://www.vt4c.com/shop/program/main.php?cat_id=22&group_id=3

Also - not sure why some are concerned about hiding the loop wire  - from my understanding of JS's recipe - it's best not to have the loop wire touching the shield more than the connection points - surely by have it concealed in an outer sleeve, it will be much closer than is ideal

I think R1200CL's idea of using Canare shielded star quad is a good choice

Michael

The wire should electrically connect only at the ends of the shield. The only other constraint should be that it does not intersect the original electric field very much. So NOT a tight helix around the shield, laying right next to the shield is fine as long as the diameter of the wire is small compared to the diameter of the shield. The insulation of the wire can touch the shield, again as long as it is significantly smaller diameter than the shield. Doing so and adding a non-conductice wrap is perfectly fine.

 

John S.

 

 

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11 minutes ago, tboooe said:

So John, is shielding a star quad cable even worth it for long runs?  Or are you saying that as long as we are using star quad there is no need for shielding? 

Properly shielded starquad is useful in situations with small signals such as microphone cables or phono cartridges. For line level interconnects it is also probably useful. For speaker cables or DC cables it is pretty much useless (it doesn't hurt, but you don't get an extra advantage for your trouble)

 

So for DC cables I would not even bother of course as long as you are using a starquad geometry.  Whatever you do, for a DC cable, do NOT go with thinner conductors JUST to get shielding, that is the wrong trade off to make.

 

John S.

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55 minutes ago, tboooe said:

Got it...the shielded star quad is a different model L-4E6S, which I think is basically the 4S6 with a shield right?  It looks like awg is a bit smaller though i dont think it will make a difference for our application.

 

I have not given up.  I emailed the vendor but have not heard back.  If I dont hear back I will try to make a shielded version myself and compare against the normal 46S.

Actually they are quite different. 4E6S is a microphone cable, it has 24AWG conductors, the 4S6 is a speaker cable with 20AWG conductors, that is quite a big difference between conductor sizes. The shielding is not worth the dramatically thinner conductors in my opinion. 

 

John S.

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1 hour ago, Middy said:

@JohnSwenson

 

I know it's shakey ground advising on AC especially on DIY....

Do the DC quad rules apply for the AC side.... Note do not use canare......?

 

I found some 5 wire 1.5mm ..16awg 

cable Steel braid double clear sleeving.

The 5th wire  exactly as the earth.

But use the 2 pair as the same method as the DC cable.

These will be manufactured parallel not twist but I believe some  medium heating below 100 Oc then mechanical twist and cool to help keep the spiral could work.

Opposite paired live neutral basic geometry but would the 5th earth wire disrupt this?

 

You don't have to answer all my ramblings but your basic thoughts would be great fully received on AC.

 

This as a cheap one stop shop and keeping within regs I think...

Doesn't have to be shielded braid, just this does for illustration purposes.

Thanks as always for helping us all

Kind regards

Dave☺

 

 

 

..

Look at this on eBay http://www.ebay.co.uk/itm/201640606005

 

 

2017-05-11 20.22.53.png

Starquad will do the same thing with AC power cable, significant decrease in inductance and built in shielding from DC on up.

 

That cable you show will not get the starquad right, you need 4 wires which form a perfect square in cress section. This cable will not do that.

 

John S.

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21 hours ago, R1200CL said:

 

How about the earth wire then?

Cause a star quad with earth, will not be a star quad or ?

(which I think was your point)

 

Edit

Just found this article that may be of interest for some of you. 

http://phmusic.co.uk/pharri5833/connections1.htm

For AC power cable you need the hot and neutral in the starquad arrangement, the ground wire is then layed next to or wrapped around the starquad.

 

VH Audio does this in their flavor 4 cable. You can get their starquad power cable for $10 a foot, plus you need a ground wire to wrap around it. Chris has not published a DIY recipe for the flavor 4, so you would have to "roll your own".

 

John S.

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1 hour ago, tboooe said:

Hey guys...pls excuse the really nooby soldering question...when I try to apply solder onto my Canare cable and the Oyaide plug, the solder just forms into little balls.  What do I need to do to make the solder "stick" to the wire and the connector?

If you are using a flux cored solder there should be enough flux to tin the wire. The little balls mean you don't have enough heat.

 

For me at least I've found the best way to do this is hold the wire in some sort of clamp, so you can hold solder in one hand and iron in the other. Melt a blob of solder on the end of the tip. Touch the tip with the melted solder to the end of the wire. Hold it there to heat the wire up. If you don't have melted solder on the tip of the iron this will take a LONG time, the melted solder transfers the heat to the wire. If you have the wire hot enough, touch the solder to the wire (NOT the iron!) and it will melt and flow into the strands by capillary action. It doesn't take very much solder to make this work.

 

If this doesn't quickly flow into the strands, you don't have them hot enough.

 

John S.

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  • 2 weeks later...
2 hours ago, Em2016 said:

 

Hi @JohnSwenson

 

Some very silly questions below but appreciate if you can help me to better understand this before I give it an attempt (I'm making some XLR and RCA cables using the Belden 1804A cable).

 

Rather than PM you more questions, I thought it's best to post here to save you from getting the same questions from others.

 

1. With the external wire, are there any special requirements or things to note for the wire to use? A recommended wire gauge or particular conductor material? 

 

2. This external wire doesn't itself need to be shielded, does it? 

 

3. Is it best to solder this external wire to the shield at each end?

 

4. Do the potential static charges you mentioned affect audio? And how would you recommend to best add a resistance from the shield to ground? In particular with making up XLR and RCA cables with this method.

 

Many thanks in advance

 

#1:

no special requirement, I wouldn't use 30AWG if you have 50 ft, 24AWG to 20AWG is probably fine. I have not done extensive testing on this, but 24-22AWG seems to work very well for normal length runs. I have been using some silicone rubber insulated 24AWG ultra flexible wire I got on Amazon.

https://www.amazon.com/dp/B01LZ8UNCV/ref=biss_dp_t_asn

 

#2:

the shield connection wire does not itself need to be shielded.

 

#3:

Yes, solder the external wire to the shield at each end. Do not solder the shield (or external wire) to the "gnd" connection on RCA cables. Connect to pin 1 at both ends for XLR. SOME configurations may not need the pin 1 connection, but assume you need it to begin with.

 

4:

you can ignore this, I shouldn't even have mentioned it.

 

John S.

 

 

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7 hours ago, Speedskater said:

Belden 1804A cable  would make a nice Star-Quad  XLR balanced interconnect cable for harsh EMI/RFI environments (like near theater lighting systems). Not something most hi-fi systems need.

But it's not a good choice for RCA unbalanced interconnects. Belden makes many good coax cables with heavy braided shields.

With it's small conductors it's a bad choice for a DC supply cable.

I'm not sure why starquad is bad for RCA, cables, IF you use the shielding topology I recommend it works spectacularly well. One pair of the quad is connected to the inner pin of the RCA plug and the other pair is connected to the outer conductor of the connector. The shield does not get connected in any way to either RCA connector, instead a separate external wire connects the two ends of the shield.

 

This construction offers exceptionally good shielding from both the shield and the starquad geometry. This is much better than coax because with coax proper shielding does not happen. Without the connection from one end of the shield to the other shielding only happens at high frequencies. With the above shielding is highly effective from DC through high frequencies. 

 

The starquad works perfectly well with a "single ended" signal, as long as the shield is NOT connected to the plugs. The "hot" and its return form a perfectly symmetrical signal for the starquad. The problem happens when you try and use the starquad with the shield the way most people do it, this results in an asymmetrical arrange which unbalances the  current in the starquad. With the shield connected the way I recommend this does not happen.

 

The only issue is that the capacitance a higher than a coax. If you are driving the cable with a high impedance output and using a long cable (100ft or more) you definitely can have a problem from the higher capacitance, but most audio gear has low enough output impedance that for normal lengths used in home audio systems this is not a problem.

 

John S.

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