Why Not Use Instrument Cable?

[Lucid_Lunatic]

I have heard tons of you guys post not to use an instrument cable to plug up your amps cabinet. I guess I'm dense on this one, but I have to ask... Why? I use speaker cables on my amps, but I have had them go out on me and use an instrument cable til I got another speaker cable. Can I screw something up like this?

 

[jerryjg]

Re: Why Not Use Instrument Cable?

in theory yes. In practise, Ivenever heard of anyone, even people who used any kind of cable they found. I wouldnt do it, but i doubt it will hurt for the short term.
Myabe if your playing balls out professionally every night. Just get a good speaker cable and be done with it.The Marshall speaker cables on ebay arent expensive and they are very good thick qulity cables.

 

[metlking]

Re: Why Not Use Instrument Cable?

I'm no expert: It's got something to do with the low resistance (or high) of an instrument cable causing harm to the output transformer, especially on a tube amp..........this is what I've always heard!

 

[Fikealox]

Re: Why Not Use Instrument Cable?

Instrument cables just can't take the current or load involved. (Speaker cables actually have a lower resistance than instrument cables, generally speaking).

 

[Gearjoneser]

Re: Why Not Use Instrument Cable?

In a pinch, you'd be better off cutting a 3 foot piece of lamp cord, and soldering 2 ends to it.

 

[ratherdashing]

Re: Why Not Use Instrument Cable?

This has been covered before many times, but I'll give you a quick explanation anyway.

The reason you use different kinds of cable is because you are dealing with two kinds of electric signal: high impedance (guitar to amp) and low impedance (amp to cab).

Your guitar sends a high impedance signal (very weak) to the amp. It is not susceptible to resistance on the cable (because it's already high impedance, a few extra ohms from the cable won't hurt it), but it is very vulnerable to RF interference. This is why guitar cables are shielded and use fairly thin wires.

The amp sends a low impedance signal to the speakers. This signal is not vulnerable to RF like a guitar signal because it is very powerful. It is, however, vulnerable to high impedance cables because the amp is only expecting a few ohms impedance, and any extra is going to change that. This is why speaker cable has no shielding and big conductors, like an AC power cord.

You can get away with using a speaker cable in place of a guitar cable, but you will probably notice you have more noise in your sound as a result. You can't get away with using a guitar cable for speaker cab connections because of the impedance problem explained above. At best you'll alter your tone, and at worst you'll wreck your output transformer.

Speaker cables are generally cheaper than guitar cables, so there's really no excuse for not using one.

 

[Sludgenutz]

Re: Why Not Use Instrument Cable?

Lucid, the tiny center conductor of a coaxial cable is both fragile, and not capable of passing large speaker current (amps).

This has nothing to do with tone, but with simple application. Don't send a Honda to the job of diesel tow truck.

The worst part about using instrument cables as speaker cables are that they are merely noisy/popping instrument cables plugged into an amp...but they equal amp death when mis-used as speaker cables. "Shorts", and "Opens" are not to be tolerated under ANY circumstance.

Most people would be better off throwing a damaged or old speaker cable in the trash, and buying a new one, rather than trusting an old/bashed cable forever.

 

[jerryjg]

Re: Why Not Use Instrument Cable?

Wanna see a *real speaker cable?..My Pro-Co Fat-Max. 8 Gauge!!;

 

[millsart]

Re: Why Not Use Instrument Cable?

Speaker cables are generally cheaper than guitar cables, so there's really no excuse for not using one.

And they are definatly cheaper than buying a new output transformer for your amp! lol

 

[PUCKBOY99]

Re: Why Not Use Instrument Cable?

YUP....accidentally used an instrument cable once into a VHT 2/50/2. Blew the fuse & fried a resistor. :smack:

 

[uOpt]

Re: Why Not Use Instrument Cable?

The "instrument" cable is actually a special cable for electric guitars with passive pickups.

Active guitars and synths are happy with mic cable.

Both mic and guitar cable have more resistance, which is usually fine. But they can have much more resistance at a joint or from kinks and still work fine for low power but overhead with amp->speaker power levels.

As you might be aware, zero load on a tube power amp breaks it. So even if you can take the efficiency loss of the higher resistance cable, you probably don't want to take the higher risk of the cable breaking.