AudioCircle
Industry Circles => Vista Audio => Topic started by: Audiovista on 9 Sep 2019, 08:35 pm
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My PC’s power cord broke, and I thought I’ll take a look. Seemed like a standard stuff, AWG18 (or cross section of 0.75mm squared):
(https://www.audiocircle.com/image.php?id=198567)
Then I cut it and what I found was very strange:
(https://www.audiocircle.com/image.php?id=198564)
Strands of wire were all oxidized and cross section looked more like AWG24 (0.25mm sq). On top of that they were kinda “springy”, I could not twist them together. Insulation is rubbery and soft. Really bad. Just to make sure, I made a trip to the local store and bought standard cable, again AWG18 (0.75mm):
(https://www.audiocircle.com/image.php?id=198568)
The difference is dramatic, in the cross section, color of the Copper, quality of insulation... best illustrated by the image below:
(https://www.audiocircle.com/image.php?id=198566)
I have seen all kinds of wire, but this is handily the worst, by far.
I can only guess that if I compared the two power cords in my system, they would sound very different :(
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One day I measured the AC cords in my spares box with a very good Ohm meter (6½ digits). I was supprised that some had a much higher end-to-end resistance than I calculated for their printed AWG.
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One day I measured the AC cords in my spares box with a very good Ohm meter (6½ digits). I was supprised that some had a much higher end-to-end resistance than I calculated for their printed AWG.
Good idea, looks like I will need to check all power and extension cords around house and in the lab.
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Wow such a great revelation for those that swear by their stock cables. :scratch:
That no doubt would easily show up in listening tests, especially on a source component. :popcorn:
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BRILLIANT !!!!
charles
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Springiness means it's made from recycled copper pipe, which is alloyed with stiffer metals. Recycled copper should be used to make new pipe, not electrical conductor.
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At least for this topic AudioScienceReview has a relevant article comparing various 12 ga. speaker cables.
https://www.audiosciencereview.com/forum/index.php?threads/when-12-gauge-wire-is-not-12-gauge.3/
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I can only guess that if I compared the two power cords in my system, they would sound very different.
Add a little Techflex and a garden hose and WOOT! Ka-Ching, Ka-Ching-Ka-Ching, Ka-Ching! :popcorn:
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:rotflmao:
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thankfully, powering your PC and not your audio gear !
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I'm sure I'm not alone in using a PC based music server for digital hirez files For me the PC is one quarter of the audio chain.
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I'm sure I'm not alone in using a PC based music server for digital hirez files For me the PC is one quarter of the audio chain.
understood, what I meant was thankfully the PC's power requirements aren't that of ones 'Class A' amps !
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Very few cable makers are spooling their own power cables. Mostly they are buying stock cable, putting a nice jacket on it, some nice connectors and up-charging. The very high prices tends to stop customers from disassembling the cables to discover that.
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There are many potential issues with cables and especially high end cables. I've seen power cables made with 12g solid core wire, this is not designed to bend repeatedly and will crack over time, causing the resistance to increase, potentially to the point it will heat up and possibly burn it's insulation. I've seen cables that can't be bent repeatedly because of the design as well. And I've seen cables who'se conductors will corrode over time, which can lead to increase in resistance.
Nevermind the blatant use of counterfeit and look alike plugs and connectors, markups in the 20x range, etc...
Just like any market, buyer beware and the more educated you are the more likely to choose a product you'll be happy with.
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I just found an extension cord where grounding wire broke. That's much more serious than line or neutral wire breaking, as it creates potentially hazardous condition and it is not detectable - most equipment will work fine, until primary insulation breaks, that is. Again, cross-section of the copper wire is nowhere near the rated one. :x
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Time to make my own extension cord... with longer and thicker cable. I am currently in Europe, hence EU receptacles and plug.
(https://www.audiocircle.com/image.php?id=198728)
(https://www.audiocircle.com/image.php?id=198723)
(https://www.audiocircle.com/image.php?id=198724)
(https://www.audiocircle.com/image.php?id=198726)
(https://www.audiocircle.com/image.php?id=198727)
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Boris do not make the mistake that it is only wire and plugs. Lose the Engineers manual and use your ears.
charles
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Boris do not make the mistake that it is only wire and plugs. Lose the Engineers manual and use your ears.
charles
I hear you Charles! Engineering and auditioning are not mutually exclusive - for the best results both need to be generously applied. Without foundation based on solid science and engineering practices we cannot be sure that a product is safe and reliable. It’ would be like having a beautiful house built out of cardboard.
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Hi Boris, Ray here, I just recently started to put together my own TT. But on this topic, I bought from Amazon, actually from Knukonceptz their 12 gauge OFC speaker wire. It is stranded with 294 strands in each PVC soft jacket. I was also looking at some Sewell OFC wire same gauge, with 259 strands in it. I didn't buy that, but us tinkerers like to play. So I would after reading that section dealing with wire resistance, I wonder what would the difference be? I was thinking about making up a power cable with this stuff, but haven't determined what two ends, (at the wall and at the equippment) to get. It's been more of a thought. Should I just leave it straight cover it with Tecflex or twist it. It could get bulky in the latter case. When I purchased this Knukonceptz cable, I was thinking at the time of skin effect. So, more strands, more conductivity. So that's all for now.
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Hey Ray,
Thanks for chiming in!
I am not very familiar with the brands that you mention, but they do seem reasonably well done - for (low voltage) speaker connections. However, I just want to verify one thing: you are looking to make a power cord right? If so please do not use speaker wire for that! There is no voltage rating, flammability rating nor regulatory approvals for use with the mains voltage. Please no! :nono:
Now, on the concept of stranded wire... I read quick verbiage from these companies on Amazon and I am not sure what they are claiming. Number of strands in a stranded wire has no meaning (other than for mechanical flexibility) and offers no electrical advantage at 60Hz over a solid wire. That is, unless each strand is separately insulated in which case it is called Litz wire. Now, Litz wire has big advantages as it reduces resistance for AC signals at high frequencies (skin effect). For line frequency there is no difference between solid wire, stranded wire and Litz wire. For audio frequencies (20Hz-20kHz) Litz wire offers some advantages (lower Ac resistance) only at high frequencies and if the conductor is thicker than AWG18 (1mm diameter).
So, for the power cord, I think you should do well with a nice AWG14 properly rated wire (stranded - for flexibility), decent plugs and, very important: clean, meticulous assembly. :D
I realize I am discussing a touchy-feely subject, but for a power cord safety must be #1 concern, as well as #2 and #3 concern :D
Cheers,
Boris
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I’ll offer up a quick recommendation on a power cable that I have been building lately. It is the Supra Lo Rad SPC edition and is silver stranded copper. It is available from seller Zendada on Ebay. It is 12 AWG and is very easy to work with. It costs $22 / meter.
It carries some certification as well, I would recommend reading up on it via their web site.
If you do purchase, there is a You Tube video that I recommend since the drain wire is connected to neutral on both sides.
With connectors, so many choices :)
Good luck and have fun.
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The drain wire is connected to the Earth (Ground) at both ends.
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The drain wire is connected to the Earth (Ground) at both ends.
Sorry about that, I got my electrical engineering degree in the south. It’s nice that things are color coded :)
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a 'drain wire' suggests that it's a shielded cord.
Moving on:
all 3 conductor AC cords and cables have a Hot, Neutral and Safety Ground (EGC)/Protective Earth wire. There is only one correct way to attach these wires at both ends.
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Connect drain wire to one end (which end) or both end?
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If the drain wire is connected to the shield/screen, I would only connect it at the component end. That way it acts as an extension of the chassis shield. If it's connected at both ends, it will also carry the leakage and noise currents that flow thru the Safety Ground/Protective Earth.
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I followed the manufacturer guidelines which is to connect at both ends. I’m really not wanting to go down a cable debate, it was a simple, relatively inexpensive option to try. I just finished my last 2 meter cable today and plan on rewriring everything with the 12 AWG cable that I mentioned as well as their 13 AWG option that is tinned copper.
It’s an inexpensive experiment that I have been wanting to try.
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This thread is about power cords. the drain refers to the safety ground (GREEN WIRE) which MUST BE connected at both ends LOL :thumb:
and has zero to do with IC.
Also a comment agree NEVER use a speaker cable for AC (unless the insulation is rated for AC line voltage use 600V is best IMO)
That original PC cord was probably made 'you know where' by 'you know who' LOL and made to be the cheapest possible cost.
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But, there are shielded power cords and that shield may have a drain wire.
Anyone that calls the green or green/yellow Safety Ground/Protective Earth wire a 'drain' should not DIY anything to do with AC power.
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Drain wire is ALWAYS associated with a shield, and it's a bad design that increases SCIN, or shield current induced noise, because it causes irregularities in the shape of the shield.
If you have a drain wire or shield on a PC it's only connected to the MALE or WALL end, because the noise the shield picks up is connected further away from the system. If you connect a shield to both ends it's simply another ground wire, and it defeats the entire purpose of having SEPARATE ground and shield.
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Anyone that calls the green or green/yellow Safety Ground/Protective Earth wire a 'drain' should not DIY anything to do with AC power.
+1 :lol:
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Good discussions!
Properly rated insulation and well connected ground wire are the key takeaways. :thumb:
Working with shields is far from simple as can be attested by anyone who spent time in an EMC lab trying to make a switching power supply (or a Class-D amplifier) compliant with FCC/CE requirements :green:
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Edit to remove my comment.
Thanks.
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Escott1377 - I'm not sure the comment was directed toward you. Perhaps the author could clarify.
As addressed before, I have never seen a drain wire in a PC that was not connected to a copper foil or braided shield.
That aside, I have seen this topic addressed authoritatively three different ways (not just here): 1)Connect drain at both ends; 2)Plug end only; 3)IEC end only. - Often mistaken, never in doubt.
Based upon what I have read and tried, I'll put my money on the plug end.
Yet when the manufacturer instructs you to connect it at both ends, what are you supposed to do?
(Rhetorical question)
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I removed my comment after reading multiple times. There have been discussions on the particular cable that I mentioned where some have tried connecting only 1 end.
Again, I followed what was recommended by the manufacturer since this is the configuration that they sell.
I apologize about my comments even if they were directed towards me as I should have just ignored.
In the final stages of our move and I was unloading a POD at 5 AM this morning before work and then heading back over after work in 90 +F degrees and well about 80% humidity.
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... 90 +F degrees and well about 80% humidity.
:o