Speaker cable question

[MartyGrass]

They say that a guitar cable should not be used to connect an amp with a speaker cabinet. Is this true? If so, why?

 

Thanks.

[kbp810]

It is absolutely true

 

Guitar cables are meant to carry a small signal, low current, and also needs to be shielded to help keep out unwanted noises... the center conductor in a high quality guitar cable should be well capable of handling the duties of a speaker wire; but even at that, the outside shielding wire is not. (and your average guitar cable's center conductor would not be well suited at all!).

 

The speaker cable needs to be able to handle much higher current, and in turn does not require any shielding.

 

You should never use a guitar cable to connect an amp to a speaker/speaker cab

[GuitArtMan]

Yes it's true. Guitar cables are typically a small gauge, I'm not sure what gauge but probably around 20 or so. Guitar cables are also shielded; in fact the correct term is single conductor shielded. The hot goes through the center of the cable while the shield is connected to ground. This works great for guitar to amp, but is not good as a speaker cable for two reasons: the gauge just isn't thick enough to handle the current; the shield actually becomes a problem in this case (I'm not sure if it radiates RF or picks up RF or both). The problem is it works and can lure you into a false sense of security. Speaker cables are two conductor, typically 16 gauge at minimum and are non shielded.

[bobmeyrick]

They say that a guitar cable should not be used to connect an amp with a speaker cabinet. Is this true? If so, why?

 

Thanks.

Yes, it is true. Speaker cables need a low resistance (around 0.1ohms) to carry a much bigger current, and consequently have thick conductors (made up of several thin conductors for flexibility). Guitar cables carry much smaller currents and have much thinner conductors - they couldn't handle the power being transferred from amp to speaker.

[MartyGrass]

I think I get it now. Now I have to buy a couple speaker cables.

 

So what's the worst case scenario pushing a speaker cabinet with a guitar cable?

[212Mavguy]

Can cause damage to your tube amp. A real speaker cable is not very expensive at all. Foolish to not have the right thing.

[kbp810]

Yep

 

Either the conductor or shielding wire could burn out and cause an open, or the middle insulator could melt and cause a short... either would be very bad for the amp. (similar to turning your amp on without a speaker/cab connected at all, which is a very, very, bad thing! - not sure if you recall my ghost in the house post regarding my 5E3)

 

About the best case scenario you will get sound that could be impacted by strange noises, buzzes, feedback, and so forth.

 

I wouldn't do it, find some speaker cables

[yoslate]

...what's that smell...?

[JohnCovach]

Maybe because combo amps have been so popular in the last several years, there are a lot of musicians I've run into--usually younger ones--who aren't aware that you should never turn your amp on unless you've got the speakers connected. For speaker cables, use the heavier gauge ones. A lot of players insist that better speaker cables lead to better tone, but who knows if that's really very true in the real world. They at least lead to better reliability.

 

I'm also surprised that some players will grab a speaker cable and use it as a guitar cord. Now that can be a noisy affair!!

[212Mavguy]

JC! Right ON!

[MartyGrass]

I got some cables at Guitar Center. I did pay extra for Monsters and doubt it will add any value. But they are gold!

 

I'm tagging my cords for speakers so there is no confusion ever.

[mars_hall]

The current that a wire can handle depends on its gauge, length, and frequency

ISo what's the worst case scenario pushing a speaker cabinet with a guitar cable?

 

Worst case is the cable is going to open up (think burned out bulb) or melt the dielectric shorting the conductors. Neither is any good for the amp output section.

 

Much depends on the wire guage and materials used. The larger the gauge, the more current it can handle. The longer it is, the more power is dissipated by the cable (heat) and the less that arrives at the speaker. The better the dielectric material (insulation), the less the chance for breakdown between conductors.

 

http://www.powerstre...m/Wire_Size.htm

[tulk1]

I got some cables at Guitar Center. I did pay extra for Monsters and doubt it will add any value. But they are gold!

 

I'm tagging my cords for speakers so there is no confusion ever.

Well, then that's GOT to be better.

 

The tagging is a great idea!

[mars_hall]

I got to thinking about it and decided to try to put together a chart that uses the current handling capabilty of the AWG gauges found in the chart at the link above and relate them to the minimum gauge cable you could use for a speaker application. Hope I haven't ignored something. Wattage is a familiar unit of power and Ohms is one for resistance or impedance. Current is measured in Amperes (A).

 

Power = Current x Current x Resistance

 

so simplified, if you have 200 watts being delivered at a 2 ohm speaker, you have 10 amps of current being delivered (i.e. 200 Watts = 10A x 10A x 2 ohms). To find the current, you just divide the wattage by the resistance (impedance) and then take the square root of the result.

 

http://www.powerstre...m/Wire_Size.htm

 

So using the chart found at the link above where we are talking about power transmission, you must have cable capable of safely carrying 10A, so the minimum AWG gauge would be 11.

 

 

Bare in mind, we are talking about the wire itself and not considering the insulating jacket material, which is generally designed to match the max requirements of the gauge and application.

[MartyGrass]

Monster cables, Halloween. It somehow made sense. I already had two pumpkins in the car and was picking up my daughter at a Halloween party.

[Hfan]

I got to thinking about it and decided to try to put together a chart that uses the current handling capabilty of the AWG gauges found in the chart at the link above and relate them to the minimum gauge cable you could use for a speaker application. Hope I haven't ignored something. Wattage is a familiar unit of power and Ohms is one for resistance or impedance. Current is measured in Amperes (A).

 

Power = Current x Current x Resistance

 

so simplified, if you have 200 watts being delivered at a 2 ohm speaker, you have 10 amps of current being delivered (i.e. 200 Watts = 10A x 10A x 2 ohms). To find the current, you just divide the wattage by the resistance (impedance) and then take the square root of the result.

 

http://www.powerstre...m/Wire_Size.htm

 

So using the chart found at the link above where we are talking about power transmission, you must have cable capable of safely carrying 10A, so the minimum AWG gauge would be 11.

 

 

Bare in mind, we are talking about the wire itself and not considering the insulating jacket material, which is generally designed to match the max requirements of the gauge and application.

Mark, Could you be more specific? Only kidding. This was a good subject. I always knew you needed speaker cables for speaker applications, now I know why.

[111518]

Here's a calculator from the Weber site. I think it is basically in line with Mars Hall's calculations, although this uses output at the amp and factors in the length of the cable, which can have a significant impact:

 

http://www.webervst.com/gauge.htm

[mars_hall]

Some make blanket statements based on hearsay without much to back up a claim. A fish has no concept of water and words are cheap.

 

Numbers can be passed and/or manipulated, but in the words of Eric; She don’t lie, she don’t lie, she don’t lie

[mars_hall]

Here's a calculator from the Weber site. I think it is basically in line with Mars Hall's calculations, although this uses output at the amp and factors in the length of the cable, which can have a significant impact:

 

http://www.webervst.com/gauge.htm

Nice calculator

[bolero]

you can also just use standard lamp power cord wire ( a tip I got from Ted Weber RIP )

 

even better: here's a tip I got from Mark Norwine, I have made a few high quality speaker cables this way

 

he carries a set of cutters in his car & any time he see's a vaccuum cleaner on the curb on garbage day etc, he cuts off the power cord because they make excellent speaker cables!

 

naturally you need to solder the 1/4" ends on

[Spectrum13]

Time for a plug.

 

I THOUGHT I had quality cables but decided to shorten the length from guitar to amp. Did not need 20 feet to my delay did not need 10 feet from delay to amp and did not need 8 feet to jump channels. For a reasonable cost, three GT cables arrived in the mail.

 

Biggest surprise when I plugged in was I forgot I was playing Lollar P90s. No hum. Huh? Before you consider a pickup swap for noiseless P90, call our own Steiner he makes the best.

[Genericmusic]

Time for a plug. Before you consider a pickup swap for noiseless P90, call our own Steiner he makes the best.

[Guest HRB853370]

I think I get it now. Now I have to buy a couple speaker cables.

 

So what's the worst case scenario pushing a speaker cabinet with a guitar cable?

 

The worst that can happen? Your speakers will turn into pumpkins at midnight if you continue this practice. Marty, quit being so frugal and invest in some high quality 24 gauge speaker cable. They are NOT that expensive and if you have been using guitar cables, you will notice the difference immediately. All the words of wisdom have been previously posted above my reply!!

[Guest HRB853370]

Time for a plug.

 

I THOUGHT I had quality cables but decided to shorten the length from guitar to amp. Did not need 20 feet to my delay did not need 10 feet from delay to amp and did not need 8 feet to jump channels. For a reasonable cost, three GT cables arrived in the mail.

 

Biggest surprise when I plugged in was I forgot I was playing Lollar P90s. No hum. Huh? Before you consider a pickup swap for noiseless P90, call our own Steiner he makes the best.

 

Now aren't you glad you took my advice Dan?

[kbp810]

Some make blanket statements based on hearsay without much to back up a claim. A fish has no concept of water and words are cheap.

 

Numbers can be passed and/or manipulated, but in the words of Eric; She don’t lie, she don’t lie, she don’t lie

But the internet wouldn't be the internet without it's plethora of blanket statements

 

You are correct, statements carry a much higher value when suppported by data, verifiable facts, and/or at least a specific detailed explanation.... something I am unfortunatley often guilty of not doing; "lazy posting", if you will.