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At what length does gauge matter?

post #1 of 12
4/17/10 at 9:05pm
Thread Starter 
I am a fan of Mogami W2893 which is a starquad of 26awg conductors, which has worked wonderfully for some short headphone cables and interconnects. At what length (extension cable) should I look at a lower awg of conductor, any? I probably wouldn't exceed 15 feet at this point.
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post #2 of 12
4/17/10 at 9:46pm
Quote:
Originally Posted by FraGGleR View Post
I am a fan of Mogami W2893 which is a starquad of 26awg conductors, which has worked wonderfully for some short headphone cables and interconnects. At what length (extension cable) should I look at a lower awg of conductor, any? I probably wouldn't exceed 15 feet at this point.
A nice table here says your 26AWG wire is 0.62 ohms for 15 ft (1.24 ohms round trip). Since your HD650 are 300 ohms, cable resistance is insignificant.

Other factors may come into play though.
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post #3 of 12
4/19/10 at 6:49pm
Thread Starter 
So at least from an impedance standpoint, as long as the wire's impedance is not greater than the impedance of the headphones, there should be no degradation in the sound?

What about capacitance? I understand that a high capacitance in a cable can impact the frequency response, but I haven't seen anything that tells me when that would occur. I don't want any high frequency roll off. Most of the lowest capacitance cables are single channel (coax) which would necessitate two separate cables twisted together which I have never seen someone do for an extension cable.

Starquad's do tend to have higher capacitance, but seem to be the natural choice for an extension cable unless I use the shield for ground with a standard two channel mic or audio cable.

I know a ton of people have made extension cables, have any of you ever looked at these figures before building?
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post #4 of 12
4/19/10 at 7:01pm
Quote:
Originally Posted by FraGGleR View Post
So at least from an impedance standpoint, as long as the wire's impedance is not greater than the impedance of the headphones, there should be no degradation in the sound?

What about capacitance? I understand that a high capacitance in a cable can impact the frequency response, but I haven't seen anything that tells me when that would occur. I don't want any high frequency roll off. Most of the lowest capacitance cables are single channel (coax) which would necessitate two separate cables twisted together which I have never seen someone do for an extension cable.

Starquad's do tend to have higher capacitance, but seem to be the natural choice for an extension cable unless I use the shield for ground with a standard two channel mic or audio cable.

I know a ton of people have made extension cables, have any of you ever looked at these figures before building?
Impedance and resistance are different factors. In impedance (the AC version of resistance), DC resistance plays a role. However, inductance and capacitance also have an effect.

Sound quality being relative, if all of the impedance was purely resistive, there should be no change in sound quality, only loudness really. However, with inductance and capacitance, there will be roll off at the ends at extreme values (think 250kHz etc.) and VERY excessive capacitance (like those Jena interconnects...) can blow your electronics.

There are twinaxial cables, but starquad should be just fine. When I use starquad for unbalanced, I use 2 conductors for signal, and 2 for ground with either a floating shield or using the shield as a drain from one end (depending on what I'm using the cable for). I also tend to build cables strictly on a need to use basis however.

Most of the values aren't important [rather, inconsequential] for consumer lengths (15ft extension cables are nothing). However, when it comes to 100-200ft patch cords for concert use, inductance and capacitance come into play. Seeing as a dynamic headphone driver don't present a purely resistive load either, slight increases in impedance due to cable build shouldn't be a big factor.
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post #5 of 12
4/20/10 at 2:50pm
Thread Starter 
Perfect Jageur, exactly what I was looking for. Basically for anything that I am going to do (low power home audio), I can use any cable that suits my purposes.
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post #6 of 12
4/20/10 at 3:19pm
you may find this page helpful for future reference.
link
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post #7 of 12
4/20/10 at 11:49pm
Thread Starter 
Awesome link, Nikongod. I bookmarked. Thanks.
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post #8 of 12
4/21/10 at 8:57am
Quote:
Originally Posted by nikongod View Post
you may find this page helpful for future reference.
link
My favorite link for this discussion as well.
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post #9 of 12
4/21/10 at 9:26am
Very interesting link... Cheers
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post #10 of 12
4/21/10 at 11:48am
Just put my DMM to my Grado extension wire, which is 15ft of standard 24AWG starquad.
0.4 Ω it showed.
Even with a low imp Grado (32Ω) it is 1/4 of the conservatively recommended 5% value.
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post #11 of 12
4/21/10 at 12:00pm
Quote:
Originally Posted by nikongod View Post
you may find this page helpful for future reference.
link
Very nice link. Thank you for sharing this info ! I've bookmarked this link in my computer.
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post #12 of 12
5/7/10 at 5:51pm
Quote:
Originally Posted by limpidglitch View Post

Just put my DMM to my Grado extension wire, which is 15ft of standard 24AWG starquad.
0.4 Ω it showed.
Even with a low imp Grado (32Ω) it is 1/4 of the conservatively recommended 5% value.

Your measurement of 0.4 ohms for 15 feet of AWG 24 agrees quite well with the value calculated using data from the Wikki wire guage table.

 

(15 feet) x (25.67 ohm)/(1000 feet) = 0.385 ohm

 

Science is great!


 

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