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Tone Tip: Speaker Cables — Use ’Em!

Dave Hunter | 09.10.2008
Welcome to the final installment of this run of my Gibson Tone Tips series. If you have been following the Tips  so far, you’ll know that most of them are simple, easy-hit suggestions that can help you maximize the performance of your guitar, amp, or effects pedals with just a little care and attention, and minimal cash outlay. This one might at first seem even simpler than most, but I have encountered so many guitarists doing it wrong that it seems worth taking the time to spell it out: when connecting an amp head to an extension cabinet, or wiring up a replacement connection in a combo amp, use a speaker cable — and by that, I mean a real speaker cable. The difference between getting this right and getting it wrong, as simple as it is, can play a big part in determining the virtue of your tone, and in preventing expensive amp repairs down the road.

When I say “real speaker cable,” I mean a two-core cable where each stranded core is of an equal gauge (thickness), and — this is the key — not a guitar cord, which has one insulated stranded “positive” wire in the middle of a braided shield serving as the “ground” connection. This might seem obvious: speaker cable for connecting speakers, guitar cords for plugging in your guitar, but the importance of getting it right stems from more than just the name on the wire. While a genuine speaker cable of good quality delivers the amp’s output equally to the speaker’s positive and negative terminals, the unequal design of a guitar cord — again, one thin insulated signal wire, surrounded by one very wide shield — introduces a lot of unwanted capacitance to the connection, which can create an impedance mismatch between amp and speaker. On top of this, the thin positive wire in a guitar cord is of a much lower gauge than you would normally want to use to make an output connection, especially from a powerful amp. The impedance mismatch will in itself strain your amp’s output tubes and output transformer, and will severely choke and dull down your tone as a result; if that thin “hot” wire inside the guitar cord gets too hot and shorts, you could blow your output transformer entirely, necessitating an expensive repair.

The trouble arises from the fact that, in the form taken by many speaker cables made for use with guitar amps, the two types of connecting cables can often look the same from the outside. Most good, modern speaker cables will have their function printed on the outer sheath somewhere, and some will be noticeably thicker than guitar cords, but if it doesn’t say, or if you just don’t know one way or the other, don’t make any assumptions. What often occurs, too, is that a guitarist buys a used amp-and-cab set that comes with a so-called “speaker cable” that the previous owner has used with it for years, and assumes this must indeed be a speaker cable … whereas the guy had been getting away with a guitar cord all along. He might have had the good fortune to avoid damaging the amp in any severe way, but his tone will have suffered at the very least, and so will yours.

How can you tell the difference, if there aren’t words on the cable to tell you? Unscrew the barrel (shield) of the plug at one end, if you can, and take a look at the connections inside. If it’s a guitar cord, you’ll very clearly see one thin “positive” wire in the center connected to the terminal from the tip of the plug, and a braided outer shield that has been twisted and connected to the ground of the plug. A genuine speaker cable, on the other hand, will have two similar looking insulated wires inside (often the insulation on one is white, the other black, but different colors are frequently used too), both of which come from the center of the cord, rather than one being a braided shield that encloses the other. If you can’t check the cable, and have even the least suspicion at all, don’t use it. Discard it, and get a genuine speaker cable. It isn’t worth taking the chance to save the $10 or $20 a decent piece of wire will cost you.

A lot of players wire up their own speaker cables. It’s easy to do, if you know the basics of soldering and have the tools, and usually saves you some money versus purchasing cables, while also giving you the option of customizing the length to suit your needs. Any good quality hi-fi speaker hook-up wire will do the job, and you can often still buy this by the foot or the yard at good hardware stores, or buy a full spool and have plenty on hand for your future needs. Very short amp-to-speaker connections within smaller combo amps can get away with 18 AWG (American Wire Gauge) wire, but I’d want to use 16 AWG for anything more than a foot or so, or 14 AWG for longer cables of two to four feet or more (this is just leaning toward the cautious—and why not, since you’re making these yourself). It’s also worth leaning toward heavier gauges for more powerful amps, which can heat up thinner wires at high output levels. Along with the cable, you just need a pair of good quality phone plugs, a soldering iron, and a little solder, and hook it all up (many plugs have screw-terminal connections, but I don’t trust them: remove the screws entirely and make a good solder connection to the terminal, so you know it’ll hold). With thicker wire gauges the larger plugs available from some suppliers will make it easier to make good connections, and to fit the screw-on barrel over the cable. Even if you have plenty of wire to use, make your cables only as long as you really need them to be and your amp will thank you for it. And while you’re at it, make a spare and carry it to every gig … so you don’t resort to using a guitar cord again out of desperation when your main cord suddenly goes missing. 

However great a guitar you’ve got, however rare and refined your priceless vintage or “boutique” tube amp, and despite the precision high-end guitar cords you might be using in front of it, using a guitar cord to make the connection between amp and speaker will instantly deplete your tone. Get a quality speaker cable, or wire up your own, and you will at least know that all the goodness you’re putting into the front end of your amp is making its way out the back.