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Positive Feedback ISSUE 35
january/february 2008


cable research labs

Gold interconnects, speaker cables, and MK IV AC power cord - A New Audiophile Credo

as reviewed Myles B. Astor


gold series speaker cables





Martin-Logan Summit.

Conrad-Johnson Premier 140M amplifiers, ART Series 3 preamplifier, Premier 15 phono stage, and PASS Labs Xono phono stage.

Altis Audio CDT-III transport and 24/96 Reference DAC, Sony SCD-1 SACD player, VPI Super Scoutmaster turntable with JMW-9 Signature arm, Lyra Titan i and Helikon, and Clearaudio Discovery cartridges.

Audioquest Amazon (Bill Low Signature) interconnects, K2 and Everest speaker cables, Cable Research Labs Gold interconnect, Silver speaker cable and Mk. II AC cords, Phoenix Gold Arx 300 Series Bronze Level interconnects, Transparent Audio Reference XL speaker, interconnect cables, and AES/EBU digital interconnect cable, Siltech Gen 3 interconnect and speaker cables, ESP Reference Essence AC cords.

Sound Application AC outlets, Goldmund cones, Symposium Platforms and Roller Blocks, Silent Running Audio VPI Turntable Platform, Silent Running Audio Craz equipment stand, Audio Physics cartridge demagnetizer, Thor Audio Phono burn-in, Cartridge Man stylus gauge, MOBIE, Walker Audio damping discs, Shatki Stones, Lyra SPT, Kontak, RRL Super Vinyl wash and RRL Super Deep Cleaner, MF Stylus cleaning fluidOznow Zero Dust stylus cleaner, Marigo Labs Window damping dots, and Cable Elevators.


Wow! Were the cable's original designers, Paul Weitzel (Tube Research Labs) and Winston Ma (First impression Music), intimately familiar with the sound of live music! Weitzel has over 150 hours of reference quality, live DSD recordings at his disposal in addition to a heavily guarded vault of open reel master tapes. (How many audiophiles know that Weitzel had one of the first audiophile SACDs in the Sony catalog?) Ma, on the other hand, sports an impressive collection of master tapes recorded at Skywalker Ranch and Ocean Way Studios—not to mention access to the Decca master tapes. And it's that's unmistakable faithfulness to that "master tape sound" that comes across when listening to the massive, Cable Research Labs Gold interconnect and speaker cables and AC power cords.

High-end audio history, unfortunately, abounds with tales of companies with great sounding products that fell by the wayside. As economic history has taught us, timing often proves more important, than the product concept, when it comes to a company's success. For some unknown reason (s), the original Cable Research Labs cables never received their just due and bounced around the high-end audio scene for many years. Eventually Winston Ma sold his interest in the company to Garth Leerer of Musical Surroundings; Leerer later sold his shares to CRL's current owner, Chip Winston.

While details surrounding the original CRL cable's design are difficult to come by, Ma did share with me a few of the product's finer points at the 2008 CES Show. According to Ma, the cable's design concept began with using different, multiple gauge, solid-core conductors for different frequency ranges. Ma added that cable stiffness proved the limiting factor when selecting for instance, the ideal gauge for low frequencies; a cable using a 10 gauge conductor would be virtually unbendable! Another key aspect of the cable's design (and resulting sound) Ma explained was the choice of the number of conductors used in the cable's return leg (not an unknown quantity among cable designers). Choice of conductor material came pretty much from much trial and error; Ma regularly travels back and forth between the US and the Far East, allowing him to bring back samples of many different types of copper wire. Each wire sample was auditioned and the best sounding cable was selected, regardless of the surrounding hype.

The newest iteration of the Cable Research Labs Gold interconnect and speaker cable retains the original cable's design concepts with a few updates to make the cables easier to manufacture, slightly more flexible and give a more professional presentation. Two of the biggest manufacturing changes to the latest version of the Gold interconnects and speaker cables include upgrading of the conductors from 2 to 6N Cu and replacing the original cable's PVC insulation with polypropylene. Without question, though, the cable's biggest change involves replacing the original cable's Cardas connectors with the relatively new and unknown Australian manufactured Bocchino RCA plugs and spades lugs.

Cable Considerations

Regular visitors to the site recognize that Cable Research Labs' top-of-line Gold interconnect and second line CRL Silver Model speaker cables were two of my 2007 Positive Feedback Online Products of the Year. At that time, the principle reason for reviewing the Silver and not the Gold speaker cables was simple: the Gold's supersized spades lugs didn't fit on the Martin-Logan Summit's binding posts. Two of the four binding post nuts couldn't be backed off far enough, and I wasn't about to strip or break them, to permit the simultaneous connection of the spade lug and the jumper connection (used in the absence of bi-wiring). Later on the proverbial light went off and I realized that a bi-wired version of the CRL Gold speaker cable would eliminate the need for the jumpers and (hopefully) provide sufficient clearance for the supersized spade lugs to be properly tightened down. So soon after the Product of the Year selections were submitted, a pair of bi-wired Gold speaker cables arrived at my doorstep.  After all is said and done, the Gold and Silver cables are cut from the same sonic cloth; the Gold simply exhibits even more realistic image dimensionality, low frequency extension, ambience retrieval, and low level resolution.

gold series speaker cables

The cable's stiffness may also complicate installation. While the breakout sections alleviate some of the wire's stress, don't expect to sharply bend either of the cables. (As a corollary, make sure the interconnect is long enough so that the cable's tension doesn't shift the equipment around.) Next, check that the speaker cable spade lugs are squarely centered in and connected to the binding post before tightening; it's also not a bad idea to hold the cable while tightening down the speaker or amplifier binding posts. Finally, be certain that The BrendaTM B3 connector's locking cylinder is firmly and securely inserted into the equipment's input jack before tightening the ClawLock™.

The AC power cords, on the other hand, are fairly flexible and the Oyaide AC plugs solidly lock into my cryogenically treated Sound Applications AC receptacles. There's no sign of droopy connections! Combined with the Gold interconnect and speaker cables, the Mk. IVs allow for the extraction of the last vestiges of low frequency extension, low level information and ambience from the rest of the audio system.

Finally, CRL breaks-in all cables prior to shipping with the Cable Cooker. Unfortunately, breaking-in cables with the Cable Cooker is an inexact science: like drugs, just because a little bit is good, more is not necessarily better. So all CRL cables are prepared "medium-rare" e.g. on the conservative side and it's clear another 50 to 100 hours more of playing are required for them to sound their best. Still for someone running a tube amplifier, 50 to a 100 hours sounds a whole lot better than 200 or 300 hours of playing. Straight out of the box, cables sounded pleasant enough, but a touch frequency and dynamically constricted. Much of these reservations disappear within 20 hours of playing—but at least another 80 hours is required to flesh out the cable's dynamic qualities.

Do No Harm

Perhaps all cable designers should take a Hippocratic oath e.g. do no harm to the sound, before being allowed to enter the high-end audio club. Until the entry of the CRL cables, choosing a reference cable was akin to voting for political candidates or choosing the lesser of two evils. Nothing drove me faster to the mute button than hyperdetailed, harmonically thin and most significantly, bright cables. There's none of those qualities in evidence with the new CRL cables. Only music! The new CRL Gold cables allowed my reference system, most notably conrad-johnson's two latest statement products, the ART Series 3 preamplifier and LP140M monoblock amplifiers, to bloom and hence, the individual qualities of each and every recording. Placing the cables atop the new Shunyata Dark Field Elevators (as compared to the older ceramic Cable Elevators) easily adds a half to one star to their performance.

The cable's most impressive attribute is its ability to amalgamate all the individual musical elements into one cohesive package.  Unlike those cables belonging to the reductionist school of reproduction, no one quality of the CRLs stands out to the detriment of another, allowing the listener to appreciate the nuances of the recording more than ever. Not only does the Gold present a synergistic balance among individual musical elements, but this balance remains unwavering across the audio frequency spectrum.

That's coupled with the CRLs incredible smoothness, liquidity, freedom from distortion and lack of grain. This smoothness doesn't come, like badly designed single-ended tube amplifier designs, at the expense of microdynamic contrasts or low level resolution. Here the liquidity comes from an absence of amusical distortions that divert the ear's attention from the music along with the ability to reproduce the harmonic overtones of instruments. As a consequence, there's a much, much greater sense of musical continuity.

Adding to the cables believability factor is their gift for recreating the spatial information and spaciousness present on the very, very best (read analog) recordings. With all apologies to digital, this quality is something that analog recordings—and most older classical or live jazz recordings—have in spades. Take for instance the ‘60s recording of Bach's Quodlibet (Telefunken SAWT 9457-A). The soundstage extends from wall-to-wall and to the furthest reaches of the back wall. Singers float in and are awash in a sea of sound while the size of the recording space, wall and ceilings are intimately revealed. Also evident in spades is the Gold's great midrange purity on the singers and harpsichord. The CRL's show how amazingly well the new conrad-johnson gear captures the overtones of the singers and the harpsichord, particularly at low volume levels.

At the same time, the CRLs have an uncanny knack of revealing how the Telefunken recording engineers balanced the sound of the volume of the harpsichord against that of the singers. Too often, the singers are too soft. This causes one turn up the volume, resulting the harpsichord sounding too loud. On Quodlibet, this balance is probably as close to real as is humanly possible.

Take for example, a somewhat larger ensemble on Songs from the Fayrfax Manuscripts (MHS 4649). One can really appreciate when played back though the conrad-johnson/CRL combination, how recording engineer Tony Faulkner carefully balanced the direct with reflected/reverberant sound in a recording space typical of that where this music might have been originally performed. Faulkner remarkably captured both the sense of hall and the top of the recording venue on this recording. Voices are extremely natural sounding, nary any sense of harshness and easy to separate. There's an uncanny feeling of a real body with real weight and dimensionality standing in front of the microphones.

There's no doubt that a great deal of the cable's ability to recreate this sense of space and ambience is directly traceable to the cable's low frequency reproduction. The cable's low frequency performance is really revealed on discs such as SuperPercussion, Carlos Chavez: Toccata for Percussion Instruments (Super Analogue SSY 19), especially especially the "2nd Movement: largo and 3rd Movement: allegro un poco marziale." (Alternatively, try the somewhat more distantly mic'ed but nevertheless excellent sounding, Gale recording of the same music). Through the CRLs, drums exhibit a tremendous dynamic range and plumb the depths of the low end. At the other end of the frequency spectrum, bells and chimes are delicately rendered and their ringing and decay lasts forever. The care that went into this recording and manufacturing is really reflected in the tremendous sense of transparency from top to bottom of the musical spectrum. In fact, the CRL cables reveal more than any other cable, the tremendous differences in transparency in recordings, be they due to record wear or production quality.

No review of the CRL cables would be complete without a listen to one of my all time favorite references, Laurence Rosenthal's Rashomon (Carlton Records STLPX 5000). Talk about taking this recording to the next level! These cables have an uncanny ability to decipher Rosenthal's complexities and subtleties especially at medium to low volume levels. The slightest twang of string instruments or shaking of bells and decay or doubling of flutes are clearly revealed. That's coupled with a tremendous soundstage with layer upon layer of instruments. For the first time, one really appreciates how the engineers sat on their hands; it actually became annoying to have to constantly raise and lower the ART's volume controls (thanks goodness for remotes!). Just how much how much dynamics lie in Rashomon's grooves is nothing short of amazing—and this disc gives nothing away to the original 1S stamper Reiner Pines of Rome on RCA (like the Pines of Rome, one wonders how many cartridges of the day could actually track this disc!).

Art of the Koto - The music of Japan Played by Kimio Eto

The cables are not, however, without their colorations. Whatever they are, however, are always consonant with the music. Yes, the cables lean ever so slightly to the warm side of neutral, and on recordings such as Kimio Eto: The Art of the Koto (Elektra EKS-7234), gently rounds the plucking of the instrument without blurring. The Golds don't have the lowest noise floor and could sound a tad more open. In this case, the ear listens through this coloration due to the robustness of the instruments. (Here I also part company with the blackness crowd; cables shouldn't have any sound or color. Blackness is just another type of noise.) A little extra warmth in the upper bass area adds just a smidge of robustness to male vocalists. Low frequencies while deep and harmonically rich, lack just the ultimate speed, slam and dynamics at the forte end of the scale. That said, how the cables are dressed has a sizable impact on their sound and the new Shunyata's Dark Field elevators greatly ameliorate these colorations.

The Result

Master tape sound—that sense of unfettered dynamics especially in the lower octaves, harmonic completeness and that elusive sense of the recording space—are present in spades in the CRL cables. For the first time in a long time, found myself listening to longer periods of time, gaining a greater appreciation of my best recordings yet hearing more redeeming virtues on those less than ultimate discs. Other cables may come through for review that do other things better than the CRLs but it will take an exceptionally well balanced cable to surpass these supersized behemoths.

Technical Highlights

Gold Interconnect and Speaker Cable

Eliminate the terminations and the interconnect and the speaker cable could be fraternal twins! Lurking inside the supersized Gold interconnects are fourteen, multiple gauge (14 to 18) 6N OFC solid-core, polypropylene insulated conductors; eight conductors are in the positive leg and six in the return leg. CRL uses small "breakout" sections so the large diameter conductors can be terminated. In the breakout section, two-14 + 18 conductors and 14 +16 gauge conductors are used in the signal and return legs, respectively.

Likewise, the speaker cables are fashioned from multiple gauge 6N OFC, polypropylene insulated conductors. Each leg of the biwired speaker cable consists of 12 conductors at the amplifier end that are split into 6 conductors/leg at the speaker end.

As if the cable's diameter and solid-core construction didn't distinguish the cables from the competition, both the Gold interconnect and speaker cables are terminated with the Australian sourced, performance enhanced, Bocchino connectors. (currently, AudioQuest is the only other US cable company using Bocchino connectors). The Gold interconnects come outfitted with the expensive (and large) Bocchino Brenda™ (the Rocket) B3 connectors while the biwired Gold speaker cables arrived replete with Bocchino's newest FM29 spades lugs.

Each Bocchino Brenda™ B3 RCA connector is milled from solid, pure (no brass) 99.94% HCOFC (High Conductivity Oxygen Free Copper). After machining, each connector is then electroplated with a minimum of 8 to 11 microns of Silver. Each FM29 spades starts with the base HFOFC; the connector's finished milled surfaces are then directly electroplated with 8 to 11 microns of Silver. Among the benefits to employing pure copper connector, according to the connector designer Carmine Bocchino, is increased electrical conductivity (especially in the nano-ohm range) that manifests itself in an extremely fast transient attack, low coloration, increased information retrieval, more spatial cues and intimacy, more relaxed feeling, increased dimensionality and dynamic range. By contrast, many high-end connectors are machined from copper alloys such as brass or bronze, because Bocchino explains, "the metal's hardness makes machining much easier."  On the other hand, "the downside to using brass or bronze," Bocchino points out, "is that brass has only 20 to 28% the conductivity of Copper (or comparable to that of Nickel)."

It's noteworthy that Bocchino eschews the use of a ferromagnetic nickel layer between the copper and gold layers. According to Bocchino, "the use of nickel makes the connector look nicer and some feel it helps maintain the gold layer but it is sonically detrimental. Other manufacturers directly gold electroplate directly onto the Copper or Copper Alloy; though this may appear a good idea from an audiopurists point of view, the Copper Metal onto which the Gold is electroplated will absorb the Gold and the connector will then begin to corrode. For this reason it is necessary to have a non-absorption barrier between the gold and the Copper."

Unlike many other connectors, the internal wires are not soldered but crimped to the body of the plug (or spade) with non-magnetic stainless steel set screws. Before compression, CRL treats the connection with an American equivalent of the copper based "Australian plumbers anti-seize compound" to minimize oxidation and enhance signal transduction.  According to Bocchino, the advantage of using a compression fitting is that, "there's no transition medium for the signal to transit to go from the wire to the interconnector metal. Further, by virtue of the wire being firmly fastened into the metal of the BrendaB3 connector, signal transfer is as pure as is technologically possible without destroying the fine crystalline structure of the wire, and the obvious audio benefits that such a linear crystalline structure affords to the clear reproduction of music."

Finally The BrendaTM B3 connector's locking cylinder (referred to as a ClawLockTM ) secures the  the RCA plug to component's input jack.  This extremely tight junction ensures as Bocchino points out, "that RF and electromagnetic interference are quickly and quietly earthed into the return path resulting is an extremely low background noise floor."

Cable Research Labs Mk. 4 AC Power Cord

mark 4 power cord

Cable Research's Labs power cords are, in contrast to the Gold interconnect and speaker cables Gold interconnect and speaker cables, a completely new design. Designed from scratch by Art Almstead (of Twisted Pair Design and the importer of the Bocchino connectors), the CRL power cords come in two flavors, the unshielded Mk. 2 and shielded Mk. 4 models for use with power amplifiers sand front end equipment, respectively. Both the Mk. 2 and 4 power cords are constructed using fine stranded 6 N OCC (Ohno cast copper) with CL3 rated PVC insulation. (Almstead finds Teflon can be edgy)

As with the interconnect and speaker cables, a great deal of thought went into the choice of connectors. In the case of the AC power cords, Almstead terminates the cables with Oyaide C-079 AC and IEC plug, in large part due to the plug's polishing process that reduces microarcing and consequently reduces AC line noise. In fact, Almstead auditioned the Rhodium, Gold and Gold Palladium plugs and found the Gold plated to work best with the CRL power cords. (according to the Oxyaide literature, the Rhodium plated connector sounds pure and bold, the Gold plated connector sounds warm, spacious and luxurious and Gold/Palladium plated connector pure, vivid and extended.)

Oyaide's designers realized that AC plugs (and connectors) must fulfill a number of critical design parameters for optimal electrical contact and electron transfer including 1) maintain their exact shape over time, 2) possess the ability to be inserted, expand and make firm, long term contact, 3) display good electrical conductivity, 4) optimum plating materials and combinations thereof and thickness and 5) proper surface finish. To accomplish their goals, Oyaide connectors use Deoxidized Phosphor Bronze as a base material, thus satisfying the ability to maintain shape, contact and conductivity. According to Oyaide, Brass, due to its inability to maintain shape and its high levels of iron and lead, is a much poorer choice. (Copper, on the other hand, is a better conductor than brass but doesn't maintain contact as well.)

For the 079 plug, Oxyaide directly electroplates a superthick 2 micron layer of 24 K gold onto the twice polished deoxidized phosphor bronze base. After electroplating, the connector's surface is polished twice again. According to Oyaide this "jewelry polished finish" increases contact area and decreases microarcing/vibration in contact area and as a result, noise caused by gapping and smearing of the signal.  (Note that like Bocchino, Oyaide avoids using a nickel substrate.) Myles B. Astor

Gold interconnects: $2600 (1 Meter)/$2800 (2 meter); Gold speaker cables: $ 2800 (6 ft); Mk. II AC power cords $795; (1½ meter, shielded or unshielded)/$895 (2 meter, shielded or unshielded).

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