Okay, let’s settle something.
Once and for all.
You hear?
You hear me?!
…hello?
Fine. I’ll just talk to this paperclip.
Mr. Paperclip, why do we keep being told not to use guitar cables as speaker cables? They look identical, and they fit in the same jack sockets. So why the insistence from Mr. Stapler over there that you absolutely must use the right one?
Well, turns out there is a reason, and it’s not just audiophile pedantry (though that does play a part).
Guitar Cables: Delicate But Necessary
Guitar cables, also known as instrument cables, are designed for high-impedance, low-power signals; the tiny electrical whispers coming from your guitar’s pickups. These signals are sensitive, easily corrupted by interference, and require shielding to stop them from picking up the hums, buzzes, and random bursts of electromagnetic jibbleflibs floating around your room.
Here’s what makes a good guitar cable:
- Shielding. Without it, your signal will turn into an obnoxious AM radio antenna.
- Low capacitance. This prevents the high-end of your tone from being slowly murdered as the signal travels down the cable.
- Durability. Because let’s be honest, you’re going to step on it. A lot.
“But what about resistance? Doesn’t that matter?”
Well, Mr. Paperclip, that’s an interesting question. But the answer is no. Not in this case. Even a bit of cheap wire won’t have enough resistance to impact a signal being fed into an amp with an input impedance in the tens or hundreds of thousands of ohms. That’s why resistance isn’t a priority for guitar cables.
“Who are you calling a bit of cheap wire, you massive, fleshy wanker?”
No, Mr. Paperclip, I’m talking about the cheap wire inside guitar cables. You, on the other hand, are made of premium-grade, high-tensile steel, meticulously engineered to hold together at least three sheets of A4 paper with unwavering determination. Your strength is legendary, but alas, even your mighty grip cannot solve the problem of impedance mismatching in audio cables.
“Fair enough”.
Now, if you’ll kindly stop taking things so personally, we can get back to the lesson at hand.
“Prick”.
Speaker Cables: The Exact Opposite
Speaker cables, on the other hand, are not dealing with tiny, delicate signals. Instead, they are hauling serious current from your amp to your speakers. This is a low-impedance, high-power situation, which means all the things that mattered for instrument cables — shielding, capacitance — are suddenly irrelevant. Instead, we have one major concern: resistance.
In a speaker cable, high resistance is bad. It saps power from your amp and can actually overheat your gear. And this is precisely why you shouldn’t use a guitar cable in place of a speaker cable. The tiny, skinny wire inside an instrument cable simply isn’t built to handle the current required by a speaker. At best, you’ll get signal loss. At worst, you’ll seriously damage something, rather like an insolent paperclip in a microwave.
A good speaker cable has:
- Thicker wire. More copper = less resistance.
- Physical durability. Because if you’re gigging, everything gets abused.
- Low resistance. Otherwise, you’re just throttling your amp.
What Happens If You Mix Them Up?
If you plug a speaker cable where a guitar cable should be, you’ll be rewarded with glorious hum, or interference from a French radio station, because speaker cables have no shielding. Your tone will be drenched in unwanted noise, which, granted, isn’t always a bad thing, but in this case can lead to much standing on chairs in the corner of the room trying to find the one spot where it’s not happening.
“So why are instrument and speaker cables identical in appearance if they serve such different purposes?”
Good question, Mr. Paperclip. The answer lies in standardised connectors — the ¼-inch (6.35mm) jack was first developed in the late 19th century for use in telephone switchboards. When early electric guitars and amplifiers emerged in the 1930s and ’40s, manufacturers adopted the same connector because it was widely available and reliable. Speaker jacks followed suit, which is why we now have two very different types of cables using the same plug.
“Crikey. So you’re saying that guitar cables are fragile little things that need shielding from the cruel world, while speaker cables are burly, no-nonsense workhorses that just need to move power with minimal resistance?”
That’s exactly right, Mr. Paperclip.
“And if you mix them up, bad things happen? Your amp could get fried, your tone could be ruined, and in extreme cases, you might accidentally summon a disembodied Frenchman into your practice space?”
Correct again, Mr. Paperclip.
“Well, in that case, I shall use my incredible tensile strength to pin a note to the notice board that says: ‘DON’T MIX UP YOUR FUCKING CABLES, IDIOT’, just in case you forget. And then, I’ll kill everyone in the world.”
A fine idea, Mr. Paperclip. A fine idea indeed.
