Speaker Vs Instrument (Guitar) cables

MisterTim

Active Member
Yes, they're both 1/4" and unbalanced. But you really shouldn't use them interchangeably.

What other argument points besides...

Instrument cable cannot handle the power and heat buildup going through them from a power amp. Instrument cable is braided shield, speaker cable is two conductor unshielded (usually...).

What else?

Instrument cable isn't necessarily a braided shield, it's just shielded.

Speaker cable is 2 conductors, instrument cable is 1 conductor and a grounded shield. They're just different.

Why do you need arguments for this?
 

jeffsw6

Member
Trying to educate the high ups about purchasing decisions.
Do musicians ever unplug their guitars before the channel/rig is muted, and produce a popping sound through the PA? If you think that could be a way to get your bosses to approve funds for guitar cords, I suggest these handy cables with special Neutrik connectors: GBNC-SILENT also available in right-angle version

If you are owning guitar cables for lending to musicians, be sure you label them very effectively and remember to collect them at the end of the gig.
 

jeffsw6

Member
So why didn't my wedge cables melt for all those years?
:rolleyes:
For the same reason that a 1000w PAR can won't melt a 16awg extension cord -- the RMS draw through the cable is insufficient to actually damage it or cause a fire. That doesn't mean it's a good idea.

Of course, a typical 22AWG instrument cable is intended for 1 amp or less, and will melt almost instantly with 40 amps. At some point between those two current values, the conductor insulation will catch on fire.

Also, damping factor of the amplifier/loudspeaker system is influenced significantly by the speaker cable.

If your monitors are run at fairly quiet levels, sure, a 22awg cable is probably not a hazard and does not audibly affect the system performance.

If you are like me, and are sometimes running 4Ω monitor circuits at 500w RMS (measured drive level, with amp into limiter and signal hovering between -6dB and -3dB from 1000w peak limit) then you can turn to Ohm's Law and find that your monitor speaker cable is probably carrying around 8 amps of current. You can then figure the temperature rise and resistance change of the 22AWG cable to find that the cable would ultimately be heated to about 130C, which would ignite the insulation, but will not be hot enough to melt the conductor itself, so if they don't short together and trip fault protection in the amplifier, the conductors will sustain a fire.

This is how electrical fires happen. Using instrument cables for loudspeakers is stupid. Why take a chance?
 

epimetheus

Well-Known Member
For the same reason that a 1000w PAR can won't melt a 16awg extension cord -- the RMS draw through the cable is insufficient to actually damage it or cause a fire. That doesn't mean it's a good idea.

Of course, a typical 22AWG instrument cable is intended for 1 amp or less, and will melt almost instantly with 40 amps. At some point between those two current values, the conductor insulation will catch on fire.

Also, damping factor of the amplifier/loudspeaker system is influenced significantly by the speaker cable.

If your monitors are run at fairly quiet levels, sure, a 22awg cable is probably not a hazard and does not audibly affect the system performance.

If you are like me, and are sometimes running 4Ω monitor circuits at 500w RMS (measured drive level, with amp into limiter and signal hovering between -6dB and -3dB from 1000w peak limit) then you can turn to Ohm's Law and find that your monitor speaker cable is probably carrying around 8 amps of current. You can then figure the temperature rise and resistance change of the 22AWG cable to find that the cable would ultimately be heated to about 130C, which would ignite the insulation, but will not be hot enough to melt the conductor itself, so if they don't short together and trip fault protection in the amplifier, the conductors will sustain a fire.

This is how electrical fires happen. Using instrument cables for loudspeakers is stupid. Why take a chance?

I'm pretty sure most cable insulation is flame retardant. While it may melt and allow the conductor to short and thus spark causing a fire, I don't think the insulation will spontaneously ignite. Somebody correct me if I'm wrong here and, if possible, provide a source of your information.
 

jeffsw6

Member
I'm pretty sure most cable insulation is flame retardant. While it may melt and allow the conductor to short and thus spark causing a fire, I don't think the insulation will spontaneously ignite. Somebody correct me if I'm wrong here and, if possible, provide a source of your information.
Most things will ignite if you get them hot enough, including electrical cable insulation. This is why cable insulation has a design temperature rating that should not be exceeded, and why you must de-rate conductors in high ambient temperature environments, depending on insulation temperature rating, to prevent cable damage or catastrophic fire.

If you need a source for this information, pick up a copy of the NEC, or read the outer jacket on different cable stock. Insulators are commonly rated for e.g. 60C 75C 90C and so on. There are de-rating tables and formulas in the NEC and its annexes.
 

epimetheus

Well-Known Member
Most things will ignite if you get them hot enough, including electrical cable insulation. This is why cable insulation has a design temperature rating that should not be exceeded, and why you must de-rate conductors in high ambient temperature environments, depending on insulation temperature rating, to prevent cable damage or catastrophic fire.

If you need a source for this information, pick up a copy of the NEC, or read the outer jacket on different cable stock. Insulators are commonly rated for e.g. 60C 75C 90C and so on. There are de-rating tables and formulas in the NEC and its annexes.

I'm very well aware on the temperature rating on conductors, I use the NEC on almost a daily basis (my day job is electrical substation design). The conductor temperature rating is not the temperature above which it will ignite though. It means the conductor will properly function at or below that temperature indefinitely. I'm not debating that a cable run hotter than it is rated for will fail, it will, eventually. I'm arguing that the insulation wont combust on its own.
 

jeffsw6

Member
I'm very well aware on the temperature rating on conductors, I use the NEC on almost a daily basis (my day job is electrical substation design). The conductor temperature rating is not the temperature above which it will ignite though. It means the conductor will properly function at or below that temperature indefinitely. I'm not debating that a cable run hotter than it is rated for will fail, it will, eventually. I'm arguing that the insulation wont combust on its own.
Well, if you are making that as a blanket statement about all electrical cable insulation, you are wrong. TPE will burn readily. Most cables with an MHSA approval for use in mines will not. Consider also that the cable may be in contact with other materials that could ignite.

Since you are in the electrical power industry, you are probably at least aware of old-style "knob and tube" wiring, with no insulator. Electricians involved in removing that crap from old buildings often note that, in some respects, it is safer than modern cable, precisely because it does not have an insulator that retains heat and can be an ignition source.
 

epimetheus

Well-Known Member
Well, if you are making that as a blanket statement about all electrical cable insulation, you are wrong. TPE will burn readily. Most cables with an MHSA approval for use in mines will not. Consider also that the cable may be in contact with other materials that could ignite.

Since you are in the electrical power industry, you are probably at least aware of old-style "knob and tube" wiring, with no insulator. Electricians involved in removing that crap from old buildings often note that, in some respects, it is safer than modern cable, precisely because it does not have an insulator that retains heat and can be an ignition source.

I was referring to the topic at hand, speaker and instrument cables. I'm not talking about power cable or any other type of cable. Are you saying that if you overloaded a speaker or instrument cable to the point of failure, the insulation would catch fire? That's all I'm trying to figure out here. I'm pretty darn sure it wont, but enlighten me.
 

MisterTim

Active Member
If you think that could be a way to get your bosses to approve funds for guitar cords, I suggest these handy cables with special Neutrik connectors: GBNC-SILENT also available in right-angle version.
These are awesome connectors, but don't pay that terrible price for them, just buy the connectors and bulk cable and make them yourself. It's $12 in parts for a silent 6' instrument cable. This is what I use on my (real) guitar cables, on Mogami W2524.

I've seen EWI mentioned quite a few times on here, but I don't know why, because every time I've looked, their prices are awful.
 
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MisterTim

Active Member
As compared to what?

Audiopile Products

I generally use Redco for this type of stuff.

Here's the price for an Neutrik NL4MP
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(because that's what's on my brain):

Redco: $1.98
Markertek: $2.06
Amazon: $2.19
Parts Express: $2.19
FullCompass: $2.58
Mouser: $2.70
MCM: $2.99
Audiopile: $3.00
AudioGear: $3.25
Sweetwater: $4.19
MusiciansFriend: $4.46
Zzounds: $4.95
B&H: $4.95
GuitarCenter: $6.99

Okay, so they're not as bad as I thought, I'm just spoiled by Redco + 25% academic discount + free shipping. But seriously, every time I've looked, Redco has the best prices on connectors and bulk cabling. Great service, too.
 
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jeffsw6

Member
I was referring to the topic at hand, speaker and instrument cables. I'm not talking about power cable or any other type of cable. Are you saying that if you overloaded a speaker or instrument cable to the point of failure, the insulation would catch fire? That's all I'm trying to figure out here. I'm pretty darn sure it wont, but enlighten me.
It depends on what type of insulation is on the cable. That is why I say TPE will burn and MHSA-approved cables won't. Copper is copper, but there are many different kinds of insulation. This really isn't a cut-and-dry yes/no. It is a case of, anyone using a 22AWG instrument cable as a speaker cable is careless and negligent, and should not be doing that given the low cost of suitable speaker cables compared to everything else we deal with.

I've seen EWI mentioned quite a few times on here, but I don't know why, because every time I've looked, their prices are awful.
It depends on what you are buying. I will admit to not having done any shopping around for similar silent guitar cables before posting that link, though; I just wanted to give the OP another idea of how he might gain approval for buying instrument cables.
 

epimetheus

Well-Known Member
It is a case of, anyone using a 22AWG instrument cable as a speaker cable is careless and negligent, and should not be doing that given the low cost of suitable speaker cables compared to everything else we deal with.

Sometimes the world just doesn't work this way. If the system works with 5 hot spots connected to one amp channel with instrument cables, it's quite difficult to convince the person who's responsible for the budget to change it.

Related to the silent 1/4" connectors, I don't like them. That's one more connection to go bad. Cables get beat to crap, especially instrument cables, in my experience. And now you want to put a reed switch in the mix? No thanks. I'll keep beating the crap out of the artists until they mute before unplugging.:twisted:
 

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