FEEDBACK ONLINE - ISSUE 21
KS 1011, KS 1021, and KS 1030 interconnects
as reviewed by Karl Lozier
In recent years, PFO and other magazines have been publishing a torrent of audio cable reviews, calling many of them the "best ever." It seems that almost everyone has gone into the cable business. Many have little experience in audio. Most either claim to have a cure for problems that we never knew existed, or claim that the revolutionary materials they use for the wire or its covering improve sound quality. Others say that "newly discovered" winding or braiding designs provide fantastic results. As many of us old-timers know, new and different is not always better. I have heard no demand for new cables, so why the proliferation? The answer seems to be that producing audio cables is simple and profitable. All that is needed is top-notch advertising and promotion, plus a glowing review in an audio publication. Newness creates interest, resulting in dozens of reviews.
Kimber Kable has been successfully manufacturing audio cables for more than twenty-five years, and enjoys the reputation of having the most extensive and up-to-date research facilities of any cable company. Ray Kimber can point with pride to over a half-million dollars of the finest test equipment, operated by professionally trained researchers. Given that, plus the largest research library around, it is no wonder that Kimber is the company that other companies try to unseat. Because magazines want to feature new products, some companies introduce new (or renamed) products almost every year. Kimber, on the other hand, says that it researched the Select series products so well that it would be difficult to make significant improvements.
When Ray Kimber established Kimber Kable in 1979, he was doing sound and light for a company in Los Angeles. Confronted with the problem of loudspeaker cables acting as antennas, he was able to cure the pickup of sound and noise by developing counter-rotating sets of conductors. Finalizing his braided-wire design resulted in a better signal-to-noise ratio (quieter background) and better musical fidelity. Kimber Kable was born, and so began thousands of tests of metals, insulations, adhesives, manufacturing protocols, connectors, stranding sizes, twisting and braiding methods, and so on—all still ongoing.
Kimber assembled a team of professionals that included an acoustical engineer, an electric engineer, a radar technician, a metrologist (no, that is not a misspelling of "meteorologist"), professional musicians and performers, audio industry veterans, and many others. Some Kimber employees have been with the company for close to twenty years. They are dedicated to research and development, not just of audio cables but microphones, specialty recording products, even loudspeakers. If anything has the potential to affect the sound quality of an audio cable, Kimber has almost assuredly researched it and tested its effects. Cryogenics is old news. The effect of color on the insulation layer of cables was researched, and the result? Clear is best. The list goes on and on.
Kimber Kable is proud of its OSCaR engineering process (Objective, Subjective, Correlation, and Results), which was developed over a period of years and uses special, proprietary sets of measurements. Kimber Kable personnel are extremely tight-lipped about these measurements. I have reason to suspect that twelve to twenty are typically performed. The result is an almost exacting correlation (better than 90 percent accuracy) between the measurements and listening evaluations. Kimber can take an audio cable and rather quickly "see" how it performs. Then they can add a strand of wire, change the gauge of all or some of the wires, or alter the insulating material, and quickly know how the resulting sound will change. They follow up with listening tests, though probably not as often as previously, and the tests probably take less time. Being able to predict how products will perform through the use of objective data allows Kimber to create cables with superior performance. They believe that their procedures have given groundbreaking results, particularly with their newer, value-priced products. I assumed (but did not ask) that the process was used to see whether any competitors were closing in on Kimber's products. Kimber is willing to compare their products with any in the world as long as the playing field is reasonably level, which means that the competitive product is in the same price range. Kimber does not go around issuing challenges, but they are confident that their products are the ones to beat.
If you were starting from scratch to design the very best cables, what factors would you consider the most important? Most would say that the choice of transmitting wire would be the starting point. What quality would be of utmost importance? How about the transmitability of electrical signals? In other words, how fast does the signal get from A to B, or from CD player to preamplifier, or from amplifier to loudspeakers? Possible choices include copper, titanium, beryllium, palladium, platinum, gold, tin, silver, and lead. Which transmits a signal the fastest? Is faster better? You also need to think about the size or thickness of the wires or strands. You might remember hearing that higher-frequency signals tend to travel on the outside of the wire, and that they move faster. Should you compensate by using thicker strands, using more skinny strands, or combining them in some sort of ratio? How many sizes should you use? If the resulting sound is a bit too bright, can you compensate by using a different covering, or perhaps a different color covering? The factors go on and on.
Silver has the greatest potential for use in audio cables because it is the best electrical conductor. Rightly or wrongly, it has earned the reputation of being bright or edgy sounding. Kimber has found that silver has to be treated very exactingly, including the way in which it is annealed and drawn through the die. Silver also seems to be critical of cable geometry. If all these factors are not correctly addressed, silver cables will sound sizzly, spitty, or bright. One attribute common to nearly all silver cable is a tight, articulate leading edge that reveals more of what is in front of it. It should be noted that gold is not a very good conductor, but does off a great "plating" to connectors due to that fact that it does not oxide.
The insulating covering, or dielectric, of an audio cable also has a profound effect on the signal, and different materials have different properties. A particularly important property is called the dielectric constant. The dielectric absorbs some of the energy of the audio signal and releases it later. How much is absorbed and released, and how quickly, are measurable. Kimber discovered that the color of the dielectric material affects the sound because the coloring agents are metallic (carbon for black, titanium for white, and so on).
For my listening tests and comparisons of several sets of Kimber cables, I decided to use the all-copper Select 1011 interconnects first, followed by the hybrid copper/silver 1021 Selects, and finally the all-silver 1030s. The zero in the last position of the model number of the Select KS 1030s indicates that there have not been any significant design changes since their introduction. The other two cables have undergone several design changes. As I understand it, the original design work was for an all-silver-conductor design, the 1030. Then came an all-copper sibling with fewer conducting strands, the 1010, and a hybrid silver/copper model, the 1020. These were attempts to retain the qualities of the 1030 at a substantially lower price. The three cables were more or less identical, except for the metals used as conductors. Therefore, any differences in sound quality can only be due to the differences in the metals used. The relatively new KS 1011s are basically copper KS 1030s, and the hybrid KS 1021s consist of half a 1011 and half a 1030.
Each model in the Select series is similarly constructed, with an inner core that helps reject interferences, including vibration. The conductors and a restraining matrix are applied together to the core. The clear-coated conductors (again to eliminate the influence of coloring agents) are readily visible under an open-weave covering that allows quick identification of the model at hand. Photographs usually reveal a small block, about half the size of a pack of cigarettes, with two holes in it through which the signal and return conductors pass. The wooden block has a directional arrow stamped onto it, and the cable model number. It is not a so-called "black box" with compensating circuitry. The block does not alter measured or audible frequency response.
In each case, I used two pairs of interconnects—one pair from the CD player to my Herron STP-2 tube preamp (see Herron for more) and the other, longer pair from the preamp to a pair of Herron M-150 solid-state amplifiers—so that differences between the one set of cables and another would be more readily apparent. The STP-2 preamp sounds particularly neutral, as only a superb tube preamp can sound. The relatively neutral power amplifiers do not betray their solid-state heritage, and do not have excessive deep- or mid-bass output or any edginess, coarseness, or irritating distortion in the treble. My Genesis G6.1 loudspeakers are highly revealing transducers, particularly in the mid and high frequencies. The CD/SACD player was a Sony DVP-S9000ES modified by Allen Wright. (This player was briefly reviewed in PFO Issue 15 by Editor David Robinson - see Sony for more.) Wright has developed an extensive, very high-quality upgrade for certain Sony two-channel players, including the original Sony SACD flagship, the SCD-1, and its counterpart, plus the SCD 777ES, the C333ES CD changer, and the DVP-S9000ES, the flagship that replaced the SCD-1. All are two-channel-only players. Wright's upgrade packages do not use vacuum tubes. The upgraded DVP-S9000ES is extremely musical. It removes edgy grunge and irritating grit from CD playback, and takes SACD playback significantly closer to its ultimate potential. It took a while to get used to the improvements, but it was a very enjoyable wait.
After a few weeks of listening solely to the upgraded Sony player (review forthcoming), I hooked up the all-copper Kimber Select 1011s. The 1011s are derived from Kimber's original all-copper Select 1010s, which were developed several years ago in response to dealer requests for high-quality interconnects that could balance the lean tonal balance of a growing number of loudspeakers. The KS 1010s became the KS 1011s by adding copper conductors, which changed the tonal balance. It is possible that the KS 1010s will offer a better tonal balance for some systems, at a lower price than the KS 1011s.
I had already tweaked the mid and tweeter controls of the Genesis speakers about an eighth of a decibel to match the sound of the newly upgraded player. One pair of the cables had approximately 150 hours of burn-in time, and the other pair had double that. My first few days of listening with the Kimber KS 1011s were done at relatively low levels. I hoped that by doing this, I would not reach any final judgments at such an early stage of the review process. Nevertheless, it was easy to discern the sonic changes. If your system is too lean in the bass and/or has a harsh or edgy treble, you will probably be pleased by the Kimber 1011s' complementary balance, but they will not be the best match for a system that has a neutral tonal balance. Irritating or edgy harshness was often pleasantly suppressed, but at the same time, positive musical qualities, including subtle details and microdynamics, were submerged. It would be logical to expect less of this effect if the system featured an integrated amp (or AV receiver), since only one pair of KS 1011s would be used. In my system, the effects were greatly ameliorated by substituting a pair of the all-silver KS 1030 cables in either position.
Next up were the KS-1021s, the copper/silver hybrids. These were developed from Kimber's original KS 1020s. As with the 1011s, the principal difference was the addition of more conductors. The 1021s share design and construction with the all-copper KS 1011s, except that the 1021s feature Kimber's unique Black Pearl silver conductors for the signal. The return has the same copper conductors found in the KS 1011s. The differences between the all- copper KS 1011s and the silver-and-copper KS 1021s were noticeable and significant. Gone was the added bass fullness and slight lack of subtle detail. The treble retained the smoothness and sweetness of the 1011s, while somehow gaining a very natural balance and offering more realistic detail.
Listening to three new Telarc discs I had received for review revealed that nothing was added to the lower registers of John Pizzarelli's guitar. The upper registers of Cheryl Bentyne's voice sounded feminine, with no added harshness or shrillness. The rhythm accompaniment on this disc is particularly good. It is also well recorded, and was reproduced well by the KS1021s. The third Telarc SACD was Mozart's Requiem, performed by Donald Runnicles with the Atlanta Symphony Orchestra and Chamber Chorus. The Kimber hybrid interconnects handled this rather large work without sounding strained or harsh. These interconnects turned out to be a real surprise. I was not expecting such excellent performance from the 1021s, but I found them to be among the three best interconnects I have heard in the past few years. At that point, I decided to see if the all-silver KS1030s could be even better.
It did not take long for the characteristics of the 1030s to emerge. Compared to the KS 1021s, which sounded very neutral, the 1030s had a slightly different sound. The bottom half of the frequency range had become a bit tighter, and a touch leaner. It was also apparent that in the upper midrange through the lower treble had a definite forwardness, though the effect was not the same as moving a few rows forward in a concert hall. I felt that I was hearing the polar opposite effect of the all-copper KS 1011s. While the hybrid KS 1021s sounded basically neutral, the all-copper 1011s sounded full, if not overly rich, and the all-silver KS 1030s sounded slightly lean and slightly bright. They were also revealing a great deal of additional detail. After a couple of hours of listening in the afternoon and a few more in the evening, I started to turn my system off, but remembered that Dick Diamond, Kimber's Director of Sales and Marketing, had mentioned that the 1030s might require a longer-than-usual burn-in time. While considering the idea that I might not have given the cables sufficient playing time, a small light bulb (or was it an LED?) went off in my brain.
The output of my new "pride and joy" CD player is much lower than that of my other players. My Herron preamplifier has a digital readout that indicates level. With the other players, the readout for serious listening had been 29. With the upgraded Sony, the readout was 52 for an equivalent listening level, so only a trickle of electric power was going into the interconnects between the player and the preamp. It might take weeks to fully burn in that cable, so I hooked up the KS 1030s to the Cary 306/200 player (which has a much higher output), placed Purist Audio Design's burn-in CD in the drawer, and played the CD for a little over forty hours.
After I reattached the KS 1030s to my reference player, the characteristics that I had previously noticed were greatly ameliorated. The "hopefully" fully burned-in 1030s still did not sound exactly like the 1021s with respect to tonal balance, but they were fairly close. The KS 1030s were now definitely superior. Their bass was a tad tighter, and it was more forceful and detailed. The upper midrange had become a bit more coherent and detailed. The differences were somewhere between subtle and slight. They would be of significance to a critical listener. Continued listening, plus more burn-in with the Purist Audio CD, resulted in a very noticeable change, which turned out to be the real thing, not the "recent memory effect" caused by simply getting used to the sound of a new component. This was the conclusion, finally, of the longest burn-in time in my memory, which includes reviewing more than a hundred cables.
With the fully burned-in KS 1030s, the bass range merged into the lower midrange flawlessly. There was no sense of anything being added. While recorded distortions were clearly revealed, they were never exaggerated. There was no hyper-detailing, just a subtly rounded exposure of musical detail. This was particularly evident in passages of loud, massed, high frequency sounds, in which the KS 1030s were able to delineate individual instruments. With all kinds of music, from large-scale orchestral music to the previously mentioned Telarc releases, the 1030s were consistently outstanding. They 1030s may offer the greatest coherence any cables within memory. I have never heard the equal of the sound I now hear in my listening room. I attribute this level of quality to the front-end components, including the Kimber Kable Select KS 1030s. This has been a busy year, and now a costly one. In addition to the fact that all of the above-mentioned components have become my references, I will be forced to add the KS 1030 interconnects to the system. The lesson here is that you should not listen to the best if you are not prepared to spend the money to purchase it.
The earlier models of the Kimber Select series had locking WBT RCA connectors. With these recent models, the newly developed WBT Nextgen connectors are available as an option. My review samples had the Nextgen connectors, which come in silver or copper. The new connectors are designed to have an impedance that is as close as possible to the desired 75 ohms. The small contact area acts in a manner analogous to the so-called star grounding system now used in preamplifiers and other components, which has the potential to eliminate eddy currents. Like all Kimber connectors, the Nextgens are round and smooth, which makes them difficult to work with on crowded component panels. I would prefer a five- or six-sided design. The new WBTs do not operate as smoothly as the old ones. They are not as impressive or confidence inspiring. Also, the contact area of the ground on the Nextgen connector is very small, and it is difficult to get a good contact unless the connector is pushed thoroughly into place. If this is done, these connectors make a better, and better-sounding, contact. Listening comparisons showed significant improvements in coherence and clarity. The improvements in sound quality were worth the extra care required when using the new connectors
It is easy to recommend Kimber's KS 1021 interconnects to anyone desiring high-performance, reasonably priced cables. To those desiring the best, go with the KS 1030s with the Nextgen silver connectors—which are now standard though the older WBT can be ordered as an option. These are the finest interconnects I have ever heard in my music system. The silver Nextgen RCAs are not an option—they are a requirement. To get the best out of the best, do not ignore the 1030s' requirement of 200 to 300 hours of burn-in time. The best always interests me. Almost the best at a significantly lower price intrigues me even more. With the Select KS 1030 interconnects and the KS 1021s, Kimber Kable has achieved both. Karl Lozier
I have to say that it is tough to argue with his findings. His evaluations parallel our own to a surprising degree. We are grateful of the time he spent evaluating the connectors as well and also concur with his findings. The new nextgen™ connectors, while offering many of the known WBT advantages such as the patented locking barrel mechanism, offer further refinements to the performance that can be expected of an RCA type connector.
After the many years that have been spent correlating scientific data and listening impressions it is gratifying to receive confirmation that your creations are providing a little musical joy.