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May 2000 EAResponsible Wiring With the advent of the Nordost cable companys Cable Burn-In Device (aka CBID 1, nicknamed The Cable Toaster) and a parallel announcement of the imminent introduction of Audiodharmas Cable Cooker[TM] 2.0, I thought it prudent to investigate the subject of cable break-in a bit more thoroughly. It would be too easy and lazy to assume carte blanche style that we need a cure for a disease when many pronounce this ailment to be utterly imaginary. Others, acknowledging the break-in phenomenon per se, have countered with a literally flippant observation -- that the listener breaks in and not the wire. Something just cracked -- did you hear that?
I contacted as many cable manufacturers as I could reach via e-mail and invited their opinions on the subject. Needless to say, the empirical evidence -- the tuned-in ear -- that has long since held that cables do sound different after a certain amount of use, found much support from those who chose to reply. This even included unexpected explanations for the sensitive few who -- some might call them dangerously obsessed -- feel that cables revert back through non-use and behave momentarily bent out of shape when moved or handled. Rather than accepting these responses at face value and concluding the whole affair to be an open-and-shut case of in flagranti derelicti, I was, in light of my columns name, professionally bound to ask "Y." If cables require break-in, why? Does continuous current over time wear down a cables peculiar reticence to drop its ego, get out of the way and just humbly serve the music? For starters, nearly everyone agreed that the perfect cable would be surrounded by air instead of a traditional dielectric. Better yet but apparently quite impractical, a true vacuum would be king. You see, a dielectric or insulator is supposed to perform just one seemingly simple function -- prevent electrical interaction between conductors and make for safe handling and installation. The perfect insulator would thus act as an absolutely inert substance. It would pass on nothing. It wouldnt interact with the host to affect the signal-carrying conductor in any way. This perfect theoretical ideal of an utterly non-conductive, purely passive medium quickly evaporates into thin air when reality hits. Bam. Air. Of course. AIR! Well, shy of suspending individual and nekkid
conductors from miniature cloth lines, which still leaves them open to radio-frequency
contamination, 100% air insulation is not practical. Why such prudish aversion to physical contact with the conductors sheathing? Simply put, DuPont Teflon -- in one form or another universally acclaimed as the dielectric of choice -- does not remain as utterly passive as air would. Being physical, it absorbs energy but also re-radiates it again. Surprisingly, most manufacturers queried agree on the plastic as the primary culprit that mandates burn-in. While some very minor details are ascribed to different cause, lets face it -- how many cable makers have the requisite state-of-the-art ultra-high-frequency-spectrum analyzers or electron microscopes to study molecular-level cable behavior themselves? Most cutting-edge cable research happens in the medical, military and aerospace industry and is concerned with burn-in procedures solely for "mean time between failure" testing, not for any change in actual performance. While audio-related observations might thus coincide perfectly between different participants, the quest to explain the rationale behind them is by force still beset with clues, hunches and theories. One relies on whats already measurably known about cables in general. One also is forced to go beyond the empirical simply in an attempt to account for all observations in audio, namely those that in the absence of not-yet-measurable proof would otherwise fall by the wayside. While some might call this mumbo jumbo, such speculative thoroughness often precipitates eventual new branches of science that manifest the old maxim "if the right question is asked, the answer invariably follows." Remember further that whatever cables these manufacturers use as basis for their opinions differ in construction, geometry, conductor and dielectric material and tolerances. Bill Lowe of AudioQuest holds that the molecules in the dielectric are being formed through exposure to current and undergo a restructuring from haphazard to uniform order over time. A dielectric thats equalized on a molecular level becomes more passive and absorbs and releases less energy. Hence it interacts less with the actual signal and causes less distortion. To prevent a re-forming to random molecular disorder at rest, Lowe recommends to leave a system playing at all times or at least powered up. This maintains a base electrical potential if not actual constant micro current in the cable. He states in no uncertain terms that prolonged non-use returns cables to near their virgin pre-conditioned state. Joe Reynolds of Nordost cites a release of gases that are trapped during the Teflon-extrusion process as one of the physical changes a cable undergoes during break-in. This is related to physical impurities in the raw conductor materials -- copper, silver or alloy -- which even in their most refined ultra-pure forms are never entirely eliminated, only minimized. As signal travels through the crystalline lattice structures of the conductive metal, it seeks the path of least resistance around impeding impurities, just as water flows around rocks and other obstructions. Over time, actual changes occur in the molecular latticework as current flow creates its own pathways. This effect, dubbed quantum tunneling, has been filmed in the UK with a very high-resolution imaging device. Reynolds is also fully aware of the impact
dielectric interaction has upon signal propagation. A dielectrics propensity to
absorb and release energy centers around a value called the dielectric constant. Pure air
or a vacuum has a dielectric constant of 1. This is used as a theoretical reference point.
A commonly employed inexpensive insulator, PVC, is plainly plagued with a high level of
time-delayed energy dissipation. It causes a smearing of the signal and can be heard as a
loss of detail, dulling of transients and a reduction of apparent speed and incisiveness.
It should come as no surprise that PVC features a very high dielectric constant from 3.5
to 5. Contrast this to the 2.1 of extruded Teflon Nordost uses in their regular cable
line. In their admittedly very expensive, top-of-the-line monofilament interconnect called
Quattro Fil, this value is undercut further to arrive at a low 1.38. For the sake of factual accuracy and as Caelin Gabriel of Shunyata Research properly reminds us, in the context of a true air dielectric -- no insulation whatsoever, being literally suspended in free space -- shielding from electromagnetic fields is entirely unaccounted for. Shielding absolutely requires an electrically conductive substance, usually in the outer cable structure, and electromagnetic fields are generated around any conductor the moment signal passes. Hence commercially viable wire billed as "air cables" still must rely on traditional shielding techniques. This is real-world stuff meeting theory and neither invalidates cables with true in-built air spaces nor the inherent performance benefits such tricky mechanical construction bestows. George Cardas of Cardas Audio corroborates with both Nordost and AudioQuest by talking about an asymmetrically distributed standing charge in the dielectric that equalizes over time. He refers to the high-voltage test that many manufacturers routinely employ to momentarily check for dielectric integrity. Such a precipitously applied voltage shock, run through conductors to check for potential shorts, causes a charged build-up that creates in turn a minute but physical expansion of the dielectric called piezoelectric effect. It settles down and dissipates only over time. This standing voltage is said to be actually measurable in the millivolt range. Its also claimed to be the cause of cable microphonics. One effect of cable conditioning or burn-in should then be the reduction or elimination of microphonic distortion. Like AudioQuest, Cardas recommends maintaining a constant low-level signal in the cable at all times. He further lists mechanically induced stress from bending and handling as contributing factor for uneven build-up of dielectric charge that, due to stray capacitance, generates whats called triboelectric noise during short-term release. Cardas has developed a proprietary fluid which, when applied to the dielectric as a thin coating, creates a certain conductivity of the outermost dielectric layer, which reduces its absorption and dissipation factor. This is said to minimize the need for break-in and again suggests that certain differences in cable geometry and materials could offset some or most benefits of burn-in. To be more blunt, before-and-after differences might range from drastic to barely noticeable. If true, après cable-burn could be less rewarding for audiophiles than après skiing is for burning muscles or libido-crazed jocks. Steven Hill of StraightWire concurs with the initial energization of the dielectrics that exhibit minor capacitive tendencies which stabilize over time. He uses as a visual analogy Saran wrap or heat-shrink and how it reacts over an object when hit with a heat gun. It shrinks, changes textures and becomes stable. When reheated, the changes are much less dramatic than during the first process. Hill cites as audible break-in changes improved midrange coherence, smoother highs and bass that can become better controlled though not more dynamic. Litzed cables, where each individual conductor is encapsulated by insulation, in his experience require more break-in than equivalent raw-conductor designs. Steve Lampen is a well-published technical writer and technology specialist at Belden Electronics Division. Belden is by far the largest US manufacturer of actual raw and pre-packaged wire. They supply many specialist cable makers in various industries other than audio, amongst them telecommunication, medical and military. The available and ongoing research in these fields is extremely sophisticated and comprehensive. However, its mostly concerned with exceedingly long runs of cables that transmit much higher frequency signals than the complex, harmonically rich waveforms found in audio, and under usually more adverse mechanical and environmental conditions. A massive corporation like Belden thus cant readily document audio-specific performance issues outside clearly measurable parameters such as capacitance, inductance and impedance. Lampen was very clear, though, that contrary to audiophile notions, Belden is very interested and committed to furthering the understanding of audio-related performance concerns. He cites as one of many examples a double-blind listening test, independently run in conjunction with Speaker Builder Magazine, to investigate the hotly disputed subject of cable directionality. [See www.belden.com/products/rahesctp.htm for detailed results]. This study gave no evidence that directionality is a controllable phenomenon. The test subjects were unable to determine by ear in which direction the cables had been manufactured. Had they been successful, Belden would have implemented such findings immediately to produce and market a superior directional wire, undoubtedly making a handsome earning with audiophiles in the process. They do, however, manufacture a number of air-dielectric cables dubbed "semi-solids." Products #9913 and #9269 use a polyethylene, #89913 and #89269 a Teflon helix to position and suspend the conductor in "thin air." Dielectric absorption is recognized as a very real phenomenon but considered of real concern mainly in the megahertz range well outside the audio band. Lampen isnt aware of any scientific evidence to support notions of dielectric equalization. If it did occur, the actual dielectric constant of the plastic would lower and affect capacitance and impedance, none of which their own testing of various powered-on, powered-off cycles over extended time segments has shown. Lampen did acknowledge that, as George Cardas mentioned, high-voltage testing is a standard procedure and does occur at Belden. However, if the piezoelectric effect claimed from such treatment were true, hed again expect a parallel change in the cables capacitance and impedance. An e-mail about high voltages stored in data cables, said to be due to high voltage testing, was in fact circulated at Belden just recently. Simply shorting the conductors will release that charge and, as far as Lampen is aware of, there is no other effect on the cable. He concurs with Cardas, though, on triboelectric noise generated from handling and flexing a cable. Beldens engineering solution to minimize such behavior are carbon-impregnated layers that "short out" inter-layer voltages, employed in Belden models #9239, 9223 and 9224.
Matthew Bond of TARA Labs began correlating measurements with subjective listening tests as early as 1987 and measured the major reason for the burn-in phenomenon in 1992. While an electron microscope would show the physical inconsistencies and imperfections in the adhesion of the dielectric to the conductor, he used an ultra-high-frequency Hewlett-Packard spectrum analyzer to monitor energy storage (frequency vs. time) in the dielectric material around a conductor. Using subtractive calculations off raw-wire values, he learned about the precise factors various tolerances and applications of dielectrics add. These results confirmed assumptions an earlier subjective experiment had generated. At that time, Bond suspended two very thin naked conductors in parallel, spaced about a 1/4" apart on a wooden jig, to create an odd-looking but functional interconnect. A parallel setup involved the same conductors but this time encapsulated in different dielectrics to allow him to listen to the sound of the dielectric in comparison. In line with Bill Lowes observations on dielectric equalization, the nude cable didnt break in whereas the dressed ones changed their sound over a period of time before they stabilized. After that, they approached but did not entirely duplicate the still superior-sounding raw cable. Based on these original experiments, a long evolutionary process of manufacturing expertise continues at TARA Labs today to implement Bonds belief that the best cable geometry is as simple as possible to minimize dielectric colorations. This resulted in the above-mentioned line of RSC Air cables. This line culminated in 1999 with the introduction of the worlds first true vacuum cable, putting the thumbscrews onto the notion that a vacuum dielectric is impossibly impractical. It actually seems to be impractical for reasons quite different than the actual manufacturing process. If Bond is to be believed, TARA Labs' The Zero turned out to be too revealing to be useful to anyone but a select few in possession of truly superior audio systems. Hence commercial release of The Zero hasnt been rushed even though fully working samples have been around for over a year. The first production run was finally scheduled for spring 2000 and The Zero is now available for those daring enough to risk utter frustration with their existing systems. Creating a gas-tight mechanical seal via internal O-rings, custom-designed RCA jacks with integral pressure valves are used to evacuate the internal air and permanently seal in the vacuum during the final manufacturing steps. On the subject of Teflons slight superiority to polyethylene with regard to their dielectric constants of 2.1 versus 2.3, Bond mentioned that polyethylene -- unlike Teflon, which doesnt remain stable -- can be infused with glass micro-spheres. Being hollow and air-filled, these spheres literally inject air into the plastic and help lower polyethylenes dielectric constant to 1.6. Matthew Bond, though very specific on many parameters, essentially copies the above statements by Bill Lowe of AudioQuest to a "T." When I showed him a pre-publication draft of this article, he verbally circled that short paragraph as being the perfectly condensed answer that succinctly explains the entire break-in phenomenon in a nutshell, everything else being superfluous. Jerry Ramsey of Audio Magic knows cable break-in to be a very real while not necessarily measurable phenomenon and uses a 120v break-in routine over a three-day period to accelerate break-in of his cables before they get shipped to a customer. Still, after uncoiling them for final installation, an additional eight hours of nonstop music playback are required to overcome the effects of uncoiling the wire from its packaging materials. On the subject of directionality, Jerry has an opinion which, taken in the context of what all these cable makers have been saying so far, sounds perfectly reasonable even though I had never thought of it that way. He claims -- and extensive listening tests with an experienced panel were used to verify this -- that cables become directional simply through use. He offers that verification of this phenomenon is easily duplicated by anyone interested. All thats required are cables of truly symmetrical design where the shield construction is identical on both ends. Simply reverse the cables after theyve been in the system for an extended period of time. Jerry suggests that the sonics will immediately and perceptibly suffer until the cable re-settles in the new direction. This requires another break-in period equal in length to the original one. This process of reversing a cables burned-in sonic directionality can be continued ad infinitum. The reason Audio Magic uses directional markers in their symmetrical designs is not to suggest that the cables are delivered directional. Its simply to remind a customer about which end is which should he rewire his system by swapping components or re-siting his audio rack. Jerry chuckled reminiscing about the early days when directionally marked cables first hit the scene. Pretty soon consumers acted as though cables without directional arrows on their jackets werent high-end any longer. Responding to this trend, a custom of directionalizing cables has taken hold of the industry ever since regardless of the, at least based on this inquiry, overwhelming absence of any available scientific documentation on the subject. Stephen Creamer of Nirvana Audio is yet another manufacturer who seconds all the above observations on dielectric equalization. Akin to Nordost's, Nirvanas solution for lowering the dielectric constant of Teflon to 1.4 involves a wrap of amorphous PTFE precisely tension-spaced with an air gap between layers. I also asked Creamer about the subject of wire directionality on which most other parties chose to remain mute. Outside of directionality being designed into a cable through asymmetrical shields, Creamer differentiates between polycrystalline copper and monocrystal versions. Polycrystals are said to behave isotropically, meaning their properties are non-directional. Conversely, single crystal copper is said to be "bi." One measurable example that might support parallel notions of audible directionality is termed the Young modulus. This gives a stiffness value for a material under tension. Single-crystal copper varies from a low 67 Gpa to a high 192 Gpa depending on orientation while polycrystalline copper retains the same 111 Gpa either way. When a conductor is flexed, crystal fracturing in the metal occurs and the signal will create a new pathway. Always one fond of creating new problems to be contemplated and agonized over by overly neurotic audiophiles, I hereby propose a new, still patent-pending conundrum: If your cable is of the monocrystal variety, how will you know what direction to bend it in so as to avoid undue fracturing? Back on track. Creamer reminds us that the best termination is no termination -- point-to-point hard wiring or surface-mount technology is inherently superior to cables that connect components via terminals of some kind. Cable termination, whether by crimping pressure or soldering heat, applies brute force to the crystalline structure of the joined materials. He feels that simply playing music through the cables and their conduit joints eventually restructures their internal molecular makeup to form new pathways between the discontinuity of dissimilar metals. This echoes Joe Reynolds observation on the quantum-tunneling effect. During the prototype phase of new Nirvana products, a panel that comprises listeners of all ages and backgrounds takes extensive notes and is compensated for time and effort with actual product. In each case, these listeners who dont know of or communicate with each other, report correlating, burn-in related changes. Some hasten this conditioning period with commercially available burn-in CDs, others use square wave and pulse generators, tuner-sourced white noise or just plain music. Creamer personally prefers the latter as it allows him to follow the process through the various stages without shortcuts. However, hes also experimented with 12,000V at 30ma for 72 hours nonstop and reports that this high-potential method proved no more effective than any others. For lack of a better word, he talks about a cable assemblys need to relax before it reveals its best performance. Before you dismiss this term -- or similar ones as to equalize, to settle-in, to become symbiotic, to get saturated -- as misplaced to describe something as inert and non-animated as cable, lets hang a quick left for a brief metaphysical detour. This will momentarily get us into far-out territory and bears no relation to Nirvana Audio despite their name. But it might help create a context for those explanations in this article that are still speculative purely as a function of technology not being available yet -- or our ignorance on knowing how -- to measure and thereby explain whats patently audible. An old and well-known hermetic dictum states "as above so below." This refers to the fact that the laws and processes of the giant extrovert universe are holographically reflected in its most minute introvert parts, and vice versa. A common example is our solar system and its reflection in a molecule -- whether it be planets and moons spinning around a sun or protons and neutrons playing catch around a nucleus, the same physical laws are operative. Its merely a matter of scale. Are you still with me? Good, because the next and immediate conclusion might leave you gasping for fresh air when the consequences hit home. Look upon your own physical body now as a truly breathtaking galaxy of billions upon billions of spinning atoms, separated by more empty space than actual matter. All of this essential emptiness is bathed in your own shifting personal moods and emotions. If youre honest, youd confess right away that being a planet or even minor shrapnel of asteroid scrap in your universe is no fun most of the time. But lets quickly change perspective to something more becoming a healthy self-image as regional ruler of your personal cosmos. There are many easy examples of actually heroic ways in which emotions affect us. How about the wimpy fellow who couldnt even do ten push-ups but lifted up an entire car by himself to free his beloved wife trapped underneath in a traffic accident? Apparently defying his own physical limitations, his extreme determination and emotional intensity affected the very atoms of neurons, synapses, adrenals and amino acids to perform a task of which he usually wasnt capable. Our conditioned outlook on the physical universe around us has us view material objects as inert, bereft of feelings and consciousness, hence immune to being affected by either. So-called miracles and magic, apparently operative outside known laws and processes, can be more readily understood if the universe is considered animated by consciousness, just as the miniature universe of our physical being is animated, manifested and constantly affected by the consciousness of "I." From here, is it too vast a stretch to conclude that the external universe, made up of endless galaxies and solar systems, is the physical body or expression of one inconceivable, fathomless consciousness which most cultures refer to as Divine? Gotcha, but back to basics. Talking about "relaxation" in terms of a cable doesnt seem as farfetched when you apply self-observation and mate it to a sensible application of the above/below law. Maybe atoms and crystals inside a metallic conductor can be happy and relaxed, stressed out and uptight, organized or in disarray. Dont dismiss this dramatized statement as utterly ridiculous Weird Coast wackiness just because our left brain has been dry-cleaned to view things in antiquated black and white opposition. I sense that some of these wire manufacturers, having spent decades getting absorbed into the minutiae of their craft, guard their own "wacky" ideas that they dont dare share openly for fear of being branded charlatans. So Im merely, unprompted and surreptitiously, doing the honors myself, like shooting blanks hoping one will turn out to be live. You might chose to call it abuse, but lets have some fun, too, while we consider all the options. When everything is said and done though, trust your own ears. Audio has a way of turning opinions into facts that is positively scary. In conclusion and acknowledging the overlap of empirical observations and subsequent conclusions above, it seems fair and necessary to pronounce cable burn-in -- and thus the conditional requirement for a break-in period -- a very real subject. To obtain the full benefit for which the cables were designed in the first place, break-in should be considered mandatory. Accessories might prove helpful to accelerate what could be a very protracted process. Theres also the distinct possibility that certain or all cables, under regular use -- plainly listening to music -- may never fully break-in to strut their stuff unhampered. Would it surprise you that arguments for the latter would come from those who market cable burn-in accessories? But cynicism aside, even George Cardas who does not market his own cable burner was plain in stating that certain wires, based on geometries or materials, could take years to fully if ever equalize. Joe Reynolds of Nordost states that experiments with their own cables, using a virgin pair versus one in constant use for 1.5 years versus a virgin one after a 48 hours toasting treatment, clearly showed that even nonstop music-only signal will not arrive at the level of performance a properly designed burn-in device can deliver in a few days. So lets hand the mike to Marc S. Wauters of Audiodharma. Hell briefly sketch a plausible scenario that could make you suspect how regardless of the disturbing extent to which your listening excesses might have degenerated of late, break-in of your cables could be an ever-receding rainbow youll never catch. Here is a bit of basic math that portrays whats going on with your amplifier/cable interface. An average amplifier is driven to full output with a 2 volts peak signal. Since most listening occurs at levels significantly more modest, the average signal voltage is typically a mere fraction thereof. Amplifier input impedances vary from 10k ohms on the low side to several 100k ohms for certain tube amps, while a typical median and effective industry standard is 47k ohms. Lets use the best-case scenario: 2 volts / 10 k ohms = 200 microamperes This current flow inside the interconnect is only factual if we were talking continuous current. However, the voltage value we used to calculate this maximum current flow is not RMS but merely a very occasional peak. For arguments sake, though, lets say you played your system under these circumstances for one week nonstop. Youd arrive at an arbitrary current-time value, or CTV, of 168 hours x 0.0002 amperes = CTV of 0.0336 Hooked up instead to Audiodharmas Cable Cooker for the same time, our interconnect is exposed to a CTV 600 times greater -- 20.16. This is induced with a constant line voltage of 12 volts and a measured current of 120 milliamperes. The accompanying literature claims that this constant current causes much higher "stress" on the dielectric than can be obtained under even the most ideal of audio system conditions. Not much to argue about here. The question remains, though, whether this proposed "stress therapy" is ultimately a good thing for the dielectric. Our cable manufacturers above refer to dielectric equalization or relaxation as the main objective of cable conditioning. Stress and relaxation would seem odd compatriots. But maybe the word stress is just poorly chosen. Lets not get hung up on verbiage. Audiodharmas beta testers report that results for an interconnect conditioned by the Cable Cooker are often audible after as little as 24 hours of use. My question now became whether, to my own ears, this difference would turn out to be merely different or an unconditional and worthwhile improvement? Or would certain parameters improve and others suffer? The Audiodharma burn-in signal is generated by a square-wave oscillator that drives a MOSFET switching circuit to produce square-wave-plus-harmonics sweeps over a frequency band of 100 to 10,000 Hz. From the same 12 volt potential, their high-current speaker output draws 1.88 amperes continuous to give a steady-state signal level in excess of 22 watts. Wauters counters theoretical attempts of using his custom signal undiluted through the regular playback chain as opposed to using the inaudible Cable Cooker. He casually warns that this would cause listeners to run for aural shelter in a heartbeat. Apparently this signal is anything but musical or pleasant. Trying to replicate its effect with some solidly slamming and jarring music over reasonably efficient speakers would quickly clip the ears of even the most stamina-endowed listeners. Should your resident white-lab-coated audiopath prescribe this type of treatment as de rigeur to cure your ailing wires, you simply must have a Cable Cooker grill them for you or else risk melting your own cochlea like chocolate. Or should it be crisp your cochlea to charcoal instead? Under this scenario, having one extended marathon audiophile session after another obviously just wont do. And there you fantasized I was giving you the perfect excuse to neglect your love life and be released from trash and garden duty. You were hoping to forego fixing that rattle in your washing machine while zoning out endlessly to tune after tune, avoiding figuring out how to regulate the power factor on your central circuit board. Sorry but no. Grab a life and let a Cable Cooker do it for you. Or so at least theory mandates. Like you, I was by now eager to compare toasted to bland cable, cooked wire to raw conduit. In all fairness, I must warn you though -- Im a sushi fanatic and raw juice junky. Cooking just doesnt do it for me. Checking in with Joe Reynolds, it became quickly clear that the primary intent for the Nordost CBID 1 is really as a tool for their dealers, not the end-user of their cables. Dealers are empowered to offer enhanced customer service by burning in cables before theyre purchased. Call it take-out night instead of having to do the dishes yourself. Of course, if you were to insist on doing it yourself, Nordost would happily sell you your own cable toaster. Before a future installment reports on actual cable testing and detailed descriptions plus features of both burn-in devices, lets summarize what we think we know so far:
Now let the experiment begin. ...Srajan Ebaen
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