What gauge wire to I need to hook up a cab?

[martinw]

Skin effect only really comes into play at much higher than audio frequencies, where it's effect is negligible.

Good quality two core mains cable is a good alternative to specialist speaker cable, and just as good.

[jpfamps]

You can work out what gauge of wire required using the following formula:

I = sqrt (W/R)

For example, to deliver 100 W into 16 Ohms:

I = sqrt (100/16) = 2.5 A

So you would require a wire rated for 2.5 amps minimum so 16/0.2 (thats 16 strands of 0.2 mm) which is rated at 3A will be fine. I generally use 24/0.2 which is rated at 6 A.

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=6198&doy=9m11#spec

Obviously it would seem that the thicker the cable the better, however if the cable is too thick it is very difficult to solder to the speaker and jack terminals.

Two further observations. I've NEVER seen speaker cable fail in an amp, even in transistor amps where the output has shorted out. Secondly, have you ever seen the guage of wire used for speaker coils? You might be surprised how small it is!


I don't advise using solid core wire as it can break more easily due to metal fatigue, especially if you are not careful stripping it and you score the wire. I often see broken solid core wires in older amps. I doubt there would be any difference in sound. It is occasionally argued that skin effect makes multicore wire  a better conductor at high frequencies so should be more trebly, however this is nonsense as skin effect only starts to become an issue a frequencies well outside the audio range.

Where anyone has cared to investigate in a scientific manner for hi-fi purposes no-one has demonstated any differences in the sounds of cables. See the link below for a good article on this by Douglas Self (someone who does really know what he is talking about).

http://www.dself.dsl.pipex.com/ampins/pseudo/subjectv.htm

[TwilightOdyssey]

^ jpfamps, my head just exploded.

Thanx for the detailed explanation. Your writing style is very easy to understand even with these complex subjects!

I'm not going to get into the 'do different cables sound different debate', as that's my bread and butter and I'm not going to incriminate myself! PDT_008

I will say that unless you've really heard ANY kind of equipment swap (including cables) on any kind of reference system, you would agree that the subjective waters get both muddy & deep very fast. (I'm not referring solely to multi kila-buck systems, but any reference system within a set price point, even though any real reference system is not going to be "cheap")

[Will]

Thanks for the good explation, wasn't finding the thread too interesting before, but I'm sure that will be a random bit of information that will stay with me  :D

[HTH AMPS]

Marshall used something around 22 gauge, so anything bigger than that.

22 gauge is like phone wire!!

I think you mean 12 gauge.

22-gauge as in a 0.022 gauge string (would 3rd on a 11 set).

The stuff Marshall uses ain't very thick at all, it's probably not even 22 gauge.

 :twisted:

??

Sorry, but now I'm really confused.

Are you referring to the gauge of a single strand, or the aggregate gauge of the wire??

A strand of 22 ga wire is NOT sufficient to carry the current demands of a amplifier's signal to the drivers in a cab.

wire gauge is based on the actual core size, not the insulating material.  the stuff you see inside a Marshall 4x12 is no different to the gauge of wire you commonly see inside a guitar pedal like a DS-1.

next time you're in Maplins/Radio Shack, have a look at some 22 guage wire and see how thin it is.  or (better still), look inside a Marshall 4x12 and see how thin the wire is.

here's some 24 gauge on the Maplins website - this is thicker than the stuff Marshall uses... http://www.maplin.co.uk/module.aspx?ModuleNo=6198&doy=8m11

 :twisted:

Interesting.

22ga is still woefully inadequate.

That 24 gauge stuff from Maplins is rated for 6A. If it was inadequate there would be Marshall cabs all over the place dropping like flies.  In reality, quite the opposite is true.

 :twisted:

[Kesus T]

The 24/ 0.2 stuff from maplins is 24 strand not 24 gauge!!!
Useable for 16ohm speaker use but at 4 ohm use, will just be over required 5A needed.
Once again Heavier, 22swg in your previous example is only the gauge of one strandin a twist. Many strands are needed to allow the passage of up to 5 A of current.
The article by Douglas self on subjectivity is only subjective itself. Think i shall remain subjective on someone elses subjectivity :lol:

[jpfamps]

22swg solid core wire is 0.771 mm in diameter and is rated for about 8 amps.

Wire rating are very conservative with respect to current carrying capacity.  Wire is rated for "permissible voltage drop" ie at the maximum rated current the voltage drop across the wire will not exceed a specified value per unit length. This is very important for power transmission over long distances. The current require to melt the cable with be much higher than this rated current, so 24/02 from Maplins will be fine for guitar cabinet wiring.

As I stated in a previous post, the wire used in speaker voice coils is surprisingly thin. It needs to be a thin as possible to keep the weigh of the voice coil down. The wire in a speaker voice coil will melt  at much lower currents than even the often very shandy wire seen in many speaker cabinets.

[Kesus T]

Are we talking about cabling from head to cab in this thread, or internal wiring of a cabinet? :?

[Elliot]

I dunno anymore - I was talking about internal wiring - In the end I used some Guitar Amp/PA cable cut up and wired. Doesn't seem to have any ill effect.

[Kesus T]

My bad! - I was only talkin about amp to cab hook-up  :oops: