All cables are created equal (?)

Audiovista · « **on:** 9 Sep 2019, 08:35 pm »

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):

Then I cut it and what I found was very strange:

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):

The difference is dramatic, in the cross section, color of the Copper, quality of insulation... best illustrated by the image below:

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

Speedskater · « **Reply #1 on:** 9 Sep 2019, 09:50 pm »

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.

Audiovista · « **Reply #2 on:** 10 Sep 2019, 10:47 am »

Quote from: Speedskater on 9 Sep 2019, 09:50 pm

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.

Nick77 · « **Reply #3 on:** 10 Sep 2019, 12:41 pm »

Wow such a great revelation for those that swear by their stock cables.

That no doubt would easily show up in listening tests, especially on a source component.

rollo · « **Reply #4 on:** 10 Sep 2019, 01:24 pm »

BRILLIANT !!!!

charles

richidoo · « **Reply #5 on:** 10 Sep 2019, 01:40 pm »

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.

jmc207 · « **Reply #6 on:** 10 Sep 2019, 02:07 pm »

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/

Wind Chaser · « **Reply #7 on:** 10 Sep 2019, 02:34 pm »

Quote from: Audiovista on 9 Sep 2019, 08:35 pm

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!

Audiovista · « **Reply #8 on:** 10 Sep 2019, 02:52 pm »

twitch54 · « **Reply #9 on:** 10 Sep 2019, 03:06 pm »

thankfully, powering your PC and not your audio gear !

Nick77 · « **Reply #10 on:** 10 Sep 2019, 03:16 pm »

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.

twitch54 · « **Reply #11 on:** 10 Sep 2019, 03:34 pm »

Quote from: Nick77 on 10 Sep 2019, 03:16 pm

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 !

Tyson · « **Reply #12 on:** 10 Sep 2019, 04:09 pm »

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.

DaveC113 · « **Reply #13 on:** 10 Sep 2019, 06:38 pm »

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.

Audiovista · « **Reply #14 on:** 12 Sep 2019, 08:39 am »

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.

Audiovista · « **Reply #15 on:** 13 Sep 2019, 06:29 pm »

Time to make my own extension cord... with longer and thicker cable. I am currently in Europe, hence EU receptacles and plug.

rollo · « **Reply #16 on:** 14 Sep 2019, 05:42 pm »

Boris do not make the mistake that it is only wire and plugs. Lose the Engineers manual and use your ears.

charles

Audiovista · « **Reply #17 on:** 15 Sep 2019, 10:03 am »

Quote from: rollo on 14 Sep 2019, 05:42 pm

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.

blindman5 · « **Reply #18 on:** 23 Jul 2020, 08:34 am »

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.

Audiovista · « **Reply #19 on:** 23 Jul 2020, 08:20 pm »

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!

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.

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

Cheers,
Boris