XLO cables-choice of materials and geometry

 

All cables are constructed using three components: the dielectric, the conductor and the termination.  The choice and quality of all three components are a function of budget considerations. Materials and manufacturing processes do make sonic differences-for the better, or the worse. How these three components are assembled is referred to as a cable’s geometry.  And at XLO, geometry is key to addressing the physics of signal transmission and key to your best choice in cables-from entry to our very best.

 

 

 

XLO dielectrics

 

In a cable, the dielectric is the insulating material surrounding and separating the conductors, and just like the dielectric in a capacitor* will store signal energy that is passed through it. This energy is stored in the dielectric during each phase of the signal’s polarity (positive or negative) and released when that polarity changes. Because the dielectric stores positive energy during the positive signal phase and negative energy during the negative, the energy that is released when the phase changes is always out-of-phase with the new signal energy coming in and will thus create cancellations and/or out-of-phase artifacts that change the original signal, and therefore the sound.

Poor quality or poorly chosen cable dielectrics are often the reason why cables have a distinct "sonic signature”. For minimum sonic effect, the dielectric in a cable must store as little energy as possible, (what is called a low dielectric constant), and it must return the stored energy in the smallest possible increment of time (what is called a high "dump rate."

DuPont Teflon has the lowest dielectric constant and the quickest dump rate of any wire insulation material now available, and Teflon or Teflon variants are the only dielectric materials that XLO uses. The ethylene polymers and co-polymers used in XLO/VDO (including proprietary products such as Elvax, Surlyn and Alathon) are much less expensive than Teflon, and come very close to matching Teflon’s performance.

The lowest performance dielectric materials are PVC compounds, thermoplastic rubbers and nylon. These are inexpensive, easy to use, and tend to have a nice texture or "feel". While many manufacturers make extensive use of these materials, XLO only use PVC for outer jacketing on its lowest cost cables.

*An energy storage device that's formed when any two electrical conductors (the "plates") are separated by any non-conductor-the dielectric.

 

 

 

XLO “field balanced” technology- a breakthrough cable geometry to definitively address electromagnetic, electrostatic fields and their interrelationship

 

XLO’s “field balanced” technology is still considered revolutionary and is at the heart of every cable XLO. Cable designs were developed to improve signal transmission by optimizing and balancing the relationship between the current-controlled electromagnetic field formed around a cable’s conductors and the electrostatic field formed around its insulation when passing an audio or digital/video signal.

When current is passed through a wire, an electromagnetic field is formed around the conductor. When the current-carrying wire is insulated, an electrostatic field is also formed around the insulation. Both of these fields – the current-controlled

electromagnetic field and the voltage-controlled electrostatic field, affect the passage of signal information, and can have a significant effect on the sound of an audio cable. Many cable designers have tried to deal with one or the other of these field phenomena (usually the electromagnetic field), but until XLO, no one had ever recognized the importance of both fields and of their interrelationship. The fact of it is that there is only one optimum relationship for the two fields, and where that relationship is present, signal transmission is materially improved.

The field-balanced geometry imposes a strict approach to a cable’s construction and explains why XLO cables look distinct from other brands and even from each other based on the intended use.

Different applications have different current- to-voltage ratios, and voltage and current control the intensity of the different fields. Phono cables pass very tiny currents at equally tiny voltages; line-level cables pass relatively very large voltages with very little current flow; and speaker cables need to be able to pass very large currents at relatively small voltages. With different current/voltage ratios creating different relative field intensities, but only a single optimum field relationship, different constructions are necessary to achieve the same point of balance.

 

 

 

XLO’s discovery and control of Capacitive Discharge Artifacts

 

Signal-destructive currents stored in a cable’s dielectrics and released out-of phase into the signal path every time an audio, digital or video signal changes Signal-destructive currents stored in a cable’s dielectrics and released out-of-polarity. By definition, a capacitor is an energy storage device formed when one or more non-conductors (the dielectric(s) separate two or more electrical conductors (the plates”). A cable meets this definition, and will, like all capacitors, store signal energy that is passed through it. This energy is stored in the dielectric during each phase of the signal’s polarity (positive or negative) and released when that polarity changes. Because the dielectric stores positive energy during the positive signal phase and negative energy during the negative, the energy that is released when the phase changes is always out-of-phase with the new signal energy coming in and will thus create cancellations and/or out-of-phase artifacts.

 

 

XLO and shielding

 

Shielding affects sound. Even shielding done the right way acts like an additional capacitor, and creates "dump artifacts" that will audibly change the sound of the system. For this reason, most XLO cables are constructed without shielding. To keep the sonic effect of shielding to an absolute minimum, XLO cables that are shielded*

are insulated with shielding spaced as far as possible from the signal conductors and grounded outside the signal path. Even so, to the critical listener, neutrality may be affected, if only very slightly. XLO recommends that, for systems of the highest resolution, shielding for line level interconnects should not be used unless severe EMI or RFI problems make shielded interconnects necessary. It's generally preferable to deal with, or accept, any shielding affects to annoying hum, noise and static problems that seriously degrade the sound.

Different shielding materials have their greatest efficiency at different frequency ranges. By using two entirely different shielding materials (copper and aluminum), XLO/HT cables offer a broader range of protection from electromagnetic (EMI) and Radio Frequency (RFI) noise and interference.

* XLO shielded cables: phono cables; HT cables

 

XLO: copper vs. silver conductors

 

With the exception of XLO digital/video cables and our least expensive analog cables, XLO cables use laboratory grade copper instead of silver. Why? For the only reason that counts--copper sounds better*.

Silver has slightly less DC resistance compared to copper, and, for this reason, some believe that silver conductors ought to sound better. However, that just isn't the case: music signals are always AC, not DC. As silver has greater self-inductance properties compared to copper, silver conductors will have a much sharper AC resistivity gradient between their center and their surface than copper conductors of the same size. As a result, silver conductor of any size and any length will always have more "skin-effect phase shift" than an identical conductor made of copper. Skin-effect phase shift helps explain a distinctive "shiny", "silvery" sound that is associated with silver conductors and preferred by some over copper.

XLO cables utilize silver conductors in megahertz-range (digital or video) applications, because at these frequencies, the signal is carried at or very near the extreme outer surface of the cable. As a result, skin-effect phase shift is not an issue.

 

 

XLO and silver-clad conductors

 

The depth to which a signal penetrates a conductor is directly related to the frequencies with lower frequencies passing through the entire conductor and higher frequency signals confined to ever-shallower passage as their frequency increases. Mega hertz-range signals, like those for digital and video, travel on or near the very surface of the conductor. By using a precisely calculated thickness of silver cladding over a high-purity copper conductor (so that signals are passing only through the silver cladding), XLO silver-clad cables are able to provide the high frequency advantages of pure silver at a very modest price.

 

 

XLO and 6N (99.99997% pure) OCC copper

 

In audio grade high-end cables and interconnects the purity of the copper is important and consequently specified to contain a percentage of “pure” copper, with the balance impurities. These are generally iron, sulfur, arsenic and additional trace elements.  Higher-purity copper is specified as 99.99997% pure and referred to as “six-nines” copper.

A second factor affecting copper’s quality for high end cables and interconnects is the actual grain structure of the copper. When copper is “drawn” to size, the process creates a grain structure that are, in effect, tiny discontinuities in the copper. These discontinuities set up tiny circuits at the grain boundaries as the signal crosses each grain. The highest-quality technique used for drawing copper is called Ohno Continuous Casting or OCC.

Pure Copper Ohno Continuous Casting” PC-OCC is manufactured by a process invented in the United States in the 1920’s. This was called “zone refining” and was used in metallurgical and physics laboratories to produce very small quantities of ultra-pure copper for experimentation. As originally practiced, “zone-refining” utilized a special crucible heated only at one point, into which ordinary copper was introduced for melting and purification. As the copper melted, the impurities in it flowed to, and stayed at the hottest point, and pure copper flowed out through a controlled off-side opening in a process of continuous casting. Because the hot purified copper was cooled only very slowly, it annealed to contain only very few extremely long crystals (as much as 700 feet). This is important because crystal junctures are where remaining impurities, including ferrous metals and sulfur, gather and interfere with signal flow: the fewer the crystal junctures, the better the copper’s performance as a conductor.

 

 

XLO and oxygen-free copper (OFC)

 

Oxygen causes oxidation, and with copper interacts to form copper oxides that can affect the copper conductor’s physical properties to degrade the sound

 

 

XLO and cryogenic treatment

 

Reserved for XLO’s higher quality cables, copper is subjected to a period of ultra-low temperature and then, slowly brought to room temperature. The process alters the molecular structure and, for some reason, results in better sound.

 

*Laboratory grade copper generally costs more than silver and can take as much as half a year between the date of order and final delivery.

 

 

XLO WaveLink Technology for digital and video

 

The wavelengths of electrical signals at audio frequencies are never less than 15 thousand meters long, and may be as long as 15 million meters. On the other hand, digital and video wavelength signals are never more than 100 meters. With the signals they carry having minimum wavelength differences of multiple orders of magnitude, it was obvious to XLO that the design parameters that optimize performance in audio cables cannot possibly be the same as those that will optimize performance in digital and video cables.

Today’s video and digital technology is truly remarkable. XLO’s insistence on cable neutrality is just as relevant in the digital/video realms as it is in the analog. XLO cables allow your audio/video system(s) to take full advantage of today’s cutting-edge signal processing.

WaveLink technology integrates materials and construction geometry to produce optimum performance for digital and video signals. As the frequency range of digital and video signals is significantly different from electric signals (analog), they require cable construction and materials uniquely needed to conduct these signals without cable interference. The benefits: Video reproduction is cleaner, sharper, brighter, with amazing resolution and breathtaking, natural colour. As for your digital system… XLO cables simply get out of the way, allowing your system to deliver it’s full potential.

 

XLO speaker cable

 

An amplifier’s “damping factor” is an expression of its ability to control the movement of a loudspeaker driver. All drivers have mass, and the greater the mass and the greater its movement, the greater the inertia that must be overcome in accelerating and decelerating its diaphragm (typically a cone) to follow the signal fed to it by the amplifier. Because the biggest (most massive) drivers in a speaker system are its woofers, and because bass signals require the most cone movement to produce, it is to accurate bass reproduction that amplifier dam

Speaker cables are functional extensions of an amplifier’s output terminals that bring an amplifier’s signal to the speakers’ inputs. Because speaker cables are part of the amplifier, they directly affect the amplifier’s effective output impedance and, in consequence, it’s damping factor – the amplifier’s ability to control the motion of the speaker’s drivers. Especially at low frequencies, that can leave your speaker’s drivers near-totally uncontrolled and can clearly and obviously affect the sound of your system.

Additionally, speaker cables, as all cables in your system, are subject to phase shift, to capacitive discharge effects, to filter effects that can actually change the frequency-response of your system, and even to something that, though of little consequence elsewhere, is of great importance for speaker cables: electromagnetic discharge effects (“EDE”) that can smear or even cancel low-level detail. The advanced design and state-of-the-art materials technology of XLO’s “Electric Series” speaker cables offer solutions to all these problems.

ping is most important.

 

XLO and balanced speaker cables

 

If you have an amplifier with balanced (also referred to as differential outputs), XLO’s balanced speaker cables are the only cables that you should consider using. All speaker cables generate Electromagnetic Discharge Effects (“EDE”) to create out-of-phase currents that can cancel low-level detail and create spurious noise artifacts. The problem is basic to physics, and, for most amplifiers, nothing can be done can to correct electromagnetic discharge effects. However, for amplifiers with balanced (or differential) output, XLO has designed special balanced speaker cables, that can reduce or eliminate EDE and add as much as 12 dB of improved resolution, imaging, and detail to the sound of your system.

 

 

XLO and bi wiring? Does it really sound better?

 

It depends.

To make speakers suitable for bi wiring, speaker manufacturers have to separate the “high-pass” and “low-pass” elements of the crossover. To allow bi wiring (as many speaker do not bi wire) manufacturers generally use a pair of stamped brass straps (jumpers) running between the two sets of binding posts. Brass jumpers are often used-an unfortunate choice- as brass among other nasty characteristics, only has about 20 percent of the conductivity of copper, and can negatively impact the sound if the speaker is used normally wired.

XLO believes that much or all of the improvement that seems to come from bi wiring may actually come about just from removing the brass straps. XLO provides “jumpers” that sound as good as bi wiring and avoids the cost of bi-wired cables.

XLO connectors and hand termination

The third component of any cable is the termination- and the choice of materials for the connectors and quality of the actual termination and connectors will affect sound quality. For this reason, XLO cables are hand terminated with XLO’s own low self-inductance, Teflon® dielectric, 24 K direct gold-plated RCA connectors or Bush-Wellman alloy conductors for balanced cables.

 

 

XLO connectors and hand termination

 

The third component of any cable is the termination- and the choice of materials for the connectors and quality of the actual termination and connectors will affect sound quality. For this reason, XLO cables are hand terminated with XLO’s own low self-inductance, Teflon® dielectric, 24 K direct gold-plated RCA connectors or Bush-Wellman alloy conductors for balanced cables.

 

Cable capacitance/inductance/impedance

 

All XLO cable lines feature very low capacitance and inductance ensuring an excellent match with a wide variety of components. A cable correctly terminated at its characteristic impedance will act as if it were infinitely long, and will pass signal with no signal reflections or standing waves*. Cable conductor capacitance is addressed by the use of a low dielectric constant to reduce or eliminate the amount of audio signal energy lost due to cable capacitance.

 

*Because both Capacitance and Inductance are reactive (capacitance trying to store energy, and inductance trying to create it), the total of the reactive factors combine with the electrical resistance of the conductor(s) to produce a new kind of analog to DC resistance which applies only to AC currents. This is called Impedance.  Characteristic Impedance is the combined effect of resistance capacitance and inductance (all of them) at a particular range of frequencies The Characteristic Impedance of a cable (or a circuit) is the impedance created by the resistive and reactive elements at a given range of frequencies.