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 Post subject: THHN Speaker Cables
PostPosted: 29 Jul 2016, 01:04 
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Joined: 28 Dec 2010, 22:07
Posts: 319
I'm currently making a pair of speaker cables from THHN wire. They are 24 inches (60cm) in length and are designed for a bookshelf layout where the amplifier sits between the speakers or in close proximity.

THHN wire is 14g stranded electrical wire sold in 500ft rolls. At the price I paid, the per-foot cost of wire is USD $0.066. I am placing on there standard banana plugs and binding each pair of wires with nylon cable ties. The result is a robust audio cable that could carry many amps of current from the amplifier to a speaker. At audio frequencies, skin effect will only raise the resistance of the cables enough to be a very small fraction of the load impedance.

Even though I'm only working with short lengths now, I can see myself making longer cables in the future if I have a better listening setup.

Ed

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 Post subject: Re: THHN Speaker Cables
PostPosted: 29 Jul 2016, 12:16 
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Joined: 08 Aug 2009, 03:11
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Location: Chilliwack, BC
Let us know how it sounds!

Two caveats I've found with household electrical wire:
1) They aren't copper, but a steel alloy and
2) "Oxygen free" is a term that will grind any helpline conversation to a halt ;)

ME: Your product [nnnnn], Is it oxygen free?
Home Depot 1-800-expert line: ......
Home Depot 1-800-expert line: What's that mean?

Good luck!

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 Post subject: Re: THHN Speaker Cables
PostPosted: 30 Jul 2016, 01:25 
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Joined: 28 Dec 2010, 22:07
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Geek wrote:
1) They aren't copper, but a steel alloy and


Where do you find that information? Below is a link to the exact wire I used. Aluminum may be used for distribution wires but that inside a house is relatively pure copper. It may not be seven-nines (99.99999%) but it is predominately copper and conducts alternating current with success.

http://www.cerrowire.com/files/file/Circuit%20Sized%20THHN-THWN2%200316.pdf

As for the Oxygen Free label, I'm not sure I'll pay extra money for copper cable labeled that. The cable I have will conduct tens of amps before it starts to heat up. If I have that problem, I can wind together multiple conductors or buy thicker wire. It will take a long length of wire or a vast amount of impurities before a reasonable length of speaker wire approaches 8 ohms in resistance.

Ed

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 Post subject: Re: THHN Speaker Cables
PostPosted: 30 Jul 2016, 03:21 
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Location: Chilliwack, BC
BowToEd wrote:
Geek wrote:
1) They aren't copper, but a steel alloy and


Where do you find that information?


By hitting it accidently with a Dremel and watching the sparks fly!

So I took some samples to my belt sander and half of them (the newer ones) threw sparks :eek:

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 Post subject: Re: THHN Speaker Cables
PostPosted: 05 Aug 2016, 15:12 
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Geek wrote:
BowToEd wrote:
Geek wrote:
1) They aren't copper, but a steel alloy and


Where do you find that information?


By hitting it accidently with a Dremel and watching the sparks fly!

So I took some samples to my belt sander and half of them (the newer ones) threw sparks :eek:


Then you have bootleg wire - probably repackaged copperweld (TM) wire that was bootlegged. Household wiring must be entirely virgin copper by code, and THHN wire is emphatically copper as described by the OP.

As to the OP - banana plugs are generally a wretched connector unless they are the cinch-type - the socket tightens onto the plug. Keep in mind that these are only friction-type connectors that may be stressed, bent, wear out from use, displaced by wandering cats and much more. Try to use a positive connector that actually clamps onto the wire and the amp.


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 Post subject: Re: THHN Speaker Cables
PostPosted: 16 Oct 2016, 11:50 
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Joined: 01 Jun 2013, 09:05
Posts: 677
GEEK wrote:

By hitting it accidently with a Dremel and watching the sparks fly!

So I took some samples to my belt sander and half of them (the newer ones) threw sparks :eek:


Quote:
Then you have bootleg wire - probably repackaged copperweld (TM) wire that was bootlegged. Household wiring must be entirely virgin copper by code, and THHN wire is emphatically copper as described by the OP.


:hot:

Yes there is something wrong if domestic mains has steel conductors. Some breaker boards used in the UK had a copper plated steel buss wire from the main breaker to the individual circuit breakers, the buss wire loosened with heat and cooling and caused the boards to set fire.
You can't clamp down very well on steel with copper/brass terminals (the steel is harder).

From a sonic point of view I like mains solid core for DC current in PSU's but I strip the PVC and replace with PTFE sleeve.
I prefer it to OFC, LCOFC is better.. :D
NB just for interest Orange drop 715 have copper plated steel lead outs and actually sound better than the 716 which has copper, but that's just horses for courses :horseshoe: <<NB no oxen..LOL

What the effect is with this plating is a weird concept, cheaper? strange..Amtrans are playing with Gold plated OFC I have never tried it.
I have tried Nickle wire and it doesn't sound like copper. What a PITA to solder :D .

Obviously Steel wire armour is a different thing.


Regards
M. Gregg

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 Post subject: Re: THHN Speaker Cables
PostPosted: 16 Oct 2016, 17:01 
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Joined: 05 Aug 2016, 14:35
Posts: 220
Geek wrote:
Let us know how it sounds!

Two caveats I've found with household electrical wire:
1) They aren't copper, but a steel alloy and
2) "Oxygen free" is a term that will grind any helpline conversation to a halt ;)

ME: Your product [nnnnn], Is it oxygen free?
Home Depot 1-800-expert line: ......
Home Depot 1-800-expert line: What's that mean?

Good luck!


Geek!!!!

You are dead wrong when you suggest, state or imply that "household wire" is any sort of steel alloy, contains steel, is made from, with or anything else to do with steel. First, that would violate several sections of the NEC, second, it would be impossible to work with, and last, it would fail in pretty short order. Copper and steel are quite galvanically active unless very specific and expensive provisions are made.... see Copperweld below.

Please supply independently verifiable proof of your statement.

Now, there is a material called "Copperweld", which is a copper-clad high strength wire typically used in highly specialized applications such as transmitting antennas, exterior high powered antennas, electric fences, invisible fences you get the picture.


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 Post subject: Re: THHN Speaker Cables
PostPosted: 16 Oct 2016, 19:03 
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Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
While I don't have that wire on hand anymore, it's not the only "copper" that contains ferrous materials.

Here's some "OFC Pure Copper" speaker wire.... yes, that's a magnet sticking to it.


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* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


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 Post subject: Re: THHN Speaker Cables
PostPosted: 17 Oct 2016, 10:50 
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Hi All, please note that there is never a reason to attack people personally on this forum.

I've edited out posts/comments that are off topic or do not comply with our rules.

Thanks,
Gio

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 Post subject: Re: THHN Speaker Cables
PostPosted: 17 Oct 2016, 11:40 
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Joined: 01 Jun 2013, 09:05
Posts: 677
Geek wrote:
While I don't have that wire on hand anymore, it's not the only "copper" that contains ferrous materials.

Here's some "OFC Pure Copper" speaker wire.... yes, that's a magnet sticking to it.


Can't get a magnet to stick to any of my cables..OFC, LCOFC or wire..
Just tried it for fun.. :eek: they would have to contain ferrous material :confused:

However some magnets won't stick to a steel car body either..LOL but that contains filler :D .
OK..I'll have a guess the speaker leads are magnetised with DC..do I win a cuddly toy?
Squirrel cage comes to mind..
:beer:

Regards
M. Gregg

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