Wire gauge and capacitance woes.

[Garbz]

Ok so we're back where I was a year ago asking questions about wire gauges.

This time round though i'm looking for speaker cables, and i'm looking at you Cat5e. Cat5e has 8 strands of 24AWG wire, Cat6 has 8 strands of 23AWG, at least this holds where i'm buying it from. All wires are solid core.

So then the question is what is the Gauge (so i can check the current rating) of 4 of these wires in parrallel, and the full 8 strands of Cat5. I guess given that I can figure out 2 and 4 lengths of cable etc.

Now part 2:

Is capacitance only affected by running the signal along with it's return close to each other? i.e. if I use one cat5 cable for +ve the other for GND how does the capacitance compare to if I use 4strands from each wire for +ve and the remaining for GND?

I've just been playing a lot with wires today and I need some phyics to ease my mind

 

[Tomo]

Hi,

I can't answer your first one, but I can tell you about the second.

The capacitance depends on the distance and the surface area. For example, a coax will have entire solenoid of charges at the mesh so ain't good if you are solely looking for low cap.

Anyways, the important thing is how the wires are placed with the jacket. If the 8 strands are placed flat, I would think capacitance will not be your problem. It wouldn't matter whether you do 1strand-7strand or 4strand-4strand since only thing that matter is distance between the wires. (I would worry about current since speakers eat current.)

If the strands are braided or crammed together, you get whole lotta uncertainties. I would think 1strand-7strand will give you less surface area to worry about, thus, less cap. But if I were you, I would do something like this.

2strand-4strand-2strand

Have the center FLOATING. This will reduce the capacitance. Also, this will reduce the probability of those 2strand's to get too close to each other. (But it's all theoretical. So fun experimenting. Don't forget to report your findings.

)

Tomo

P.S. Dood Can I make this MY IDEA and copyright?

 

[BlazerFRS]

Wire gauge is determined by the cross sectional area of conductor in the wire.

Since a 23AWG wire has a cross sectional area of .0003173 square inches, 4 in parallel gives a total cross sectional area of .0012692 square inches; ALMOST equivilant to 18AWG (which is .001276 square inches).... I'd think of it as 20AWG just to be safest.

8 in parallel gives an area of .0025384 square inches, ALMOST equivilent to 15AWG (which is .002558 square inches)... I'd consider this 17 or 18AWG to be safe.

Hope this helps you out!

I used this chart to do the math, BTW:
http://www.thepanelshop.com/Wire_table.htm

 

[GWN]

I find this calculator very handy when calculating total AWG from multiples of the same gauge or multiples of different gauge.

http://home.hiwaay.net/~rgs/awgcalculator.html

As BlazerFRS mentioned 4 strands of 24 AWG is around 18 AWG and 8 is around 15 AWG.

 

[Garbz]

Thanks for the wire gauge calculator and theory guys.

Just to clarify on capacitance. The wires are cat5e. 4 x twisted pair configuration. What i'm asking is if there's any different between running both signal and return through the same length of cat5e, or just a signal.

I.e. is capacitance lower if the return is run down a separate length of wire? Think of it as a twisted mess of 16 conductors or 2x 8 conductors separated.

 

[Carbonman]

For speaker cable, worry more about inductance for its impact on sound quality. The only time capacitance is really an issue with speakers is if the amp goes into oscillation because the capacitive load is too great to drive.
Interconnects are where capacitance becomes a big issue regarding sonics. Inductance is less serious an issue here.
Of course, keeping RCL as low as possible in all situations and running the shortest cable lengths possible are the rules of thumb to follow.

 

[mono]

Quote:

is capacitance lower if the return is run down a separate length of wire? Think of it as a twisted mess of 16 conductors or 2x 8 conductors separated.

Yes it should be lower... how much I can't tell you.

 

[Garbz]

Ok thanks. Time to go get out the box and give these buggers a try

/EDIT: Oh another question for you. How does inductance fit into it? I know resistance is caused by the size, length and type of conductor, but what causes inductance?

 

[looser101]

In case you missed it there was a link in a recent thread that will probably answer most of your questions. It deals with speaker cables and includes different configurations for Cat5.

Link

All the best,

-R-

 

[Garbz]

Thanks. No i didn't miss it, but I did loose it. It actually gave me the idea to throw some cat5 at my bass drivers since the Eichmann speaker cables while the highs are fantastic seemed a bit muddy in the lows.

Actually everything worked very well. Currently running 4 lengths to each speaker and the cat5 is powering only the bass driver. Vast improvement over the eichmanns in a single cable config.