capacitance

When we started playing a few decades ago, guitar cables had sproingy coils and crackled when we moved. They cut out after a dozen or so gigs and were basically something to be fought with. Unavoidably, they had an adverse impact on our sound. Today, cables comprise a multi-tiered industry of their own, ranging in price and design from just a few bucks for a no frills wire to thousands of dollars for the kind of cutting edge technology that you’ll only find in the best studios on the planet. Somewhere in between is a world of choices that can be overwhelming once you start exploring what a “good cable” is all about. For some, “good” means absolute neutrality. Then again, neutrality might be the last thing you want – consider Hendrix’ penchant for high capacitance coily cords due their ability to tame the highs of early Strats that had no tone control for the bridge pickup. Depending on your gear and the sound you’re looking for, there is a cord out there that will do exactly what you need it to do – open up your mids, make you a little spankier, make you a little boomier, etc. Of course, even the best sounding cable might not be the thing for you if it can’t hold up to the rigors of your particular drill. Great-sounding cables made for the studio might be fine for the guy who uses the over/under wrapping method religiously and doesn’t move an inch on stage, but what about the guy who jumps around a lot and can’t wrap a cord to save his life?

Before we proceed we feel it is necessary to address those of you who still haven’t drunk the punch on the idea of high-end cables improving your tone. We’ll put it to you this way, don’t knock ‘em ‘til you’ve tried ‘em.

Early Enlightenment

As we started trying out the cables you’ll read about here, our conversations ran to things like, “Hey, this one would be great for jazz,” or “Y’know, this one is a lot brighter than those others,” and “This one’s really punchy!”

There really are sonic differences between guitar cables and those differences have everything to do with a cable’s design. Some are more traditional, with a stranded conductor inside a shield. Some use two conductors plus a full shield. Some seek out premium copper and shielding materials. Some go even farther yet in their eternal quest for tone. And – beyond the wire – we found a lot of difference in the feel of these cables.

Right off, we need to tell you that if you’re after an answer to “What’s the best sounding cable?” or “What’s the best cable value?” you’ve come to the wrong place. This is not a shootout: essentially, once you get past the generic house-brand cables, “best” becomes a relative term. So instead of picking a winner, we’re going to focus on five things about our batch of cables: design, sound, durability, handling characteristics – and for the more timid among us, we’ll factor in the price, too.

• By design, we refer to the materials that were chosen and the way they were assembled. This includes the number and kind of conductors, the shielding design, the jacket material and the kinds of plugs. Ultimately, design affects sound, durability and handling.

• Sound is a subjective element. Rather than developing a set of para-scientific tests, we took cables into a studio setting, played through them, and got feedback from each other and from our bandmates. We chose not to record cables and get lost in waveforms and plotted response curves which are impossible to gauge accurately when used with a guitar or bass played by human hands. So instead of testing these cables assembly line-like, we worked with them for a while and treated them like a musician would, not a scientist. We spent time with them and began to appreciate their differences. What we noticed most in the cables were their frequency response, detail, transient response, and their punch.

• Differences in handling tend to stand out when you spend a lot of time with a lot of different cables. Flexibility of cables was quickly notable, with some flopping nicely on the floor and others always remaining in loops. Some cables had a rough feel. Some were soft and cozy. Overall, we maintain that sound is paramount, but a few cables lost favor with us because of their handling characteristics.

• We also thought that durability of a cable was important. A key consideration was the kind of strain relief at the plugs, but we also thought about the durability of the conductor and shielding materials and the choices of jacket and insulation materials.

• Price is a factor for all of us to some degree. Because of their cost, price – at some point – will likely outweigh choosing a cable that seems to have an ideal balance of design, sound and feel. But when you’ve put out plenty of cash for just the right guitar and amp, it’s a shame to sell your gear short with a mediocre performing cable that just won’t last.

But First…The Geek Factor

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We all know that a guitar cable is just a wire that carries a signal from the instrument to the amplifier. However, that wire must be shielded from noise sources that are ubiquitous in our modern environment, whether from nearby magnetic fields (such as your amplifier’s transformers), from nearby power lines and house wiring, and even from radio frequencies that fill the air around us. (Just plug in your guitar with an unshielded speaker cable and you’ll struggle to hear your tone over all the humming and buzzing.)

A cable is typically shielded via a braided conductor attached to ground that surrounds the insulator of the inner conductor. The inner conductor itself must be fully capable of carrying the voltage produced by the pickup, which isn’t too tough an assignment in the case of a guitar cable – we’re talking about voltages in the 0.1V to 1.0V range.

The shield may also carry signal by design, since the signal is composed of a positive and negative phase. The inner conductor carries the + signal and is termed “hot.” The negative signal is called the “return” and is usually carried by the shield which in this case must be connected at both ends.

Some designers use a separate second wire to carry the return signal. The shield encircles both wires, which is then connected to ground on only one end. In that case, the shield only serves to protect from external sources of noise – it doesn’t actually carry a signal like with a single conductor cable.

The theory with this two-conductor-plus-shield design is that it reduces the tendency of the + signal to bleed to ground through the shield. There are some high end manufacturers that insert another type of shield between the signal wires and the ground shield, too. This is often a thin conductive carbon polymer. One cable designer we talked with explained that the extra shield helps prevent the + signal from seeking a route to ground and thus reinforces the strength of the signal.

Where the Rubber Meets the Shield

Just under a cable’s jacket made of rubber, plastic, cloth or other material, you’ll find a metallic shield formed from thin copper strands and wrapped in either a flat spiral or a braid. Some cables also use a shielding made of aluminum foil reinforced with polymer film. This second kind of shield is usually not the sole source of shielding in a cable, but is instead usually combined with the spiral or braided copper shield.

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The effectiveness of the shield is directly proportional to the surface area of insulator that it covers and is expressed as a percent (usually over 90%). Spiral wrap is favored in many high end cables because of a proposed advantage in signal carrying ability and completeness of wrap, while braided shield is quite a bit stronger and resistant to physical distortion. A very tight braided shield makes for a stiff cable.

Following the Conductor

The conductor of choice in most cases is copper, though there are high end cables using silver for its increased conductance. Whatever wire gets used has inherent resistance (that weakens your signal) and the interaction between shield and core also induces a capacitance in the cable (which hides those sparkling highs). Conductors used in guitar cables may be solid or made up of fine strands often wrapped together in a spiral – and sometimes the strands are braided together in a complex configuration, as well.

If copper strands are used they may be bare or tinned with a metal coating. The idea here is that the all-important high frequencies tend to be carried at the very exterior layer of the copper strands. If left untinned, there may be some oxidation over time which will interfere with these surface-seeking high freqs and reduce their presence. However, tinning them with solder also reduces their conductance. To compensate, some manufacturers tin with silver, which theoretically might enhance and protect the highs.

...the capacitance of a cable is considered one of its most important design parameters. The lower the capacitance the better the high frequency response. That does not necessarily mean that the lowest capacitance cable is the best sounding – but it’s a step in the right design direction.

But designing a cable’s conductor is even more complex. Some cables use extremely fine strands of copper, while some have a lesser strand count – expense is a factor in this decision. Some solid copper conductors use techniques to align the copper molecules to theoretically enhance signal. They may also use a special subinsulator to protect the copper from flexion fatigue. Stranded copper is stronger in this regard and doesn’t need special protection. Solid silver conductors are more susceptible to fatigue and breakage. Some cable designers, citing transmission line theory, use a twisted pair of center conductors for the hot signal. There even are designs that use two complete cables twisted together and then joined at each connector to achieve their sonic goal.

Insulated From Reality

The material used to insulate the internal signal wire is also of major importance. Basically, this material is what separates the two signal paths. Insulation is a dielectric (non conductive) material that is rated according to its insulating abilities by what is called a “dielectric constant.” The importance of insulation in cable design is that with two current-carrying surfaces separated by a dielectric material, a capacitor is created. The larger the value of the capacitor, the greater tendency it has to conduct high frequencies to ground – just like in your guitar’s tone control.

As you probably guessed, the capacitance of a cable is considered one of its most important design parameters. The lower the capacitance the better the high frequency response. That does not necessarily mean that the lowest capacitance cable is the best sounding – but it’s a step in the right design direction.

Luckily, in recent years even inexpensive cables have been able to achieve fairly low capacitance due to development of better dielectric materials based on polyethylene and other polymers. Older cable designs depended on rubber or neoprene insulators, both of which yield much higher capacitance. High-end cables may use enhanced polymers to lower capacitance even more. The thickness of the insulator and as well as its geometric accuracy may also affect the ultimate cable sound.

Frequency Transmission

What started off as a discussion about an innocent piece of wire with a couple of shiny plugs has gotten quite complex. One last thing needs to be considered – how guitar frequencies are transmitted by a cable.

Most basically, the signal carried by a cable’s conductors has bandwidth – a sound’s lowest to highest frequencies. In the case of an electric guitar or bass, this bandwidth is not really all that wide. The signal sent from the guitar also has phase relationships among its frequencies, which are defined by the string vibrating in the magnetic field of the pickup, and then affected by the character of the wire in your cable.

In all, creating a great-sounding cable is certainly not a matter of chance. How a designer puts all of these cable parameters together creates and defines a cable’s sound and character. And those are key factors making a guitar cable more or less attractive to you, the potential buyer.

At Last - Digging Into the Pile of Cables

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For this two-part article, we will review more than a dozen cables from 11 manufacturers. Some could be considered exotics, while others are basic but sturdy. The least expensive cable we looked at was in the $30 range, but several had an MSRP of $50 to $100 – with several exotics listing for $150 or more.

In the end, we received so many cables that we had to break up this article into two parts. This part discusses a range of premium cables that generally lists for less than $75. The next installment will take on cables that tilt toward the exotic – and the expensive. In that part, we’ll also bring you comments from cable designers themselves that dig into the theory behind their super-high-end cables.

To learn about these cables, we took them into our rehearsal studio– where you can really hear sonic detail – and gave them a close listen through our rigs at home as well. As nerdy as it might sound, we really spent some quality time with these pieces of wire.

For bass, Dan tested cables with a passive ’74 Fender Jazz Bass and a recent active G&L L-2500 five-string into a hi-fi SWR Workingman’s 12 bass amp. On guitar, Bob played a Tom Anderson Cobra Special-S with Anderson mini humbuckers plugged into a David Allen “Old Flame” with a Weber 15” Californian speaker.

In this first article, we will review seven cable designs from four manufacturers, organized by brand, and then from highest to lowest price. For each cable, we’ll begin with the manufacturer’s description of the cable’s makeup and the list price. Then we’ll share our impressions of their design, sound, handling and durability. Remember, Bob will present the guitar player’s perspective, while Dan will speak for the low-enders among us.

Pro Co

Bob’s overview:First I have to make full disclosure. I am a Pro Co fan. I have gigged with the same set of Pro Co cables for the past 15 years or so and have never had a problem with either sound or durability. I used one of these old cables as my go-to reference in listening tests.

Lifelines Line Cable (MSRP $51.49)
15’ cable with transmission line design with 4-conductor microphone cable connected in pairs, spiral shield attached at one end only, double plastic strain relief, G&H plugs.

Bob says: I found this cable to have a sweet full sound across the entire guitar tonal spectrum with a goodly amount of punch, presence and detail. It is a bit thicker and heavier than the cables I am used to but lays down nicely on stage and coils well at the end of the gig when the last thing you want to do is wrestle with an uppity cable. It is built like the proverbial brick house with double strain relief and Kevlar fiber running down the middle to prevent the cable from stretching. It also incorporates some high tech cable design by utilizing double twisted pairs to handle the signal and a unipoint ground on the shield.

Dan says: This is a great full frequency cable for bass - excellent transient response, clear and detailed sound. It has a particularly thick jacket, but thankfully, it’s rubbery and flexible, if a bit heavy. I really appreciate the double heat-shrink strain relief; that makes for a cable that should last a long time. Using black heat-shrink for the amp end of the cable is a nice touch.