Whether youre looking to build your first system or upgrade to better sound, when it comes to speaker cables and interconnects, youll find no shortage of choice in todays audio marketplace. Cable offerings crop up (and disappear) frequently, and a buyer faces a sometimes-bewildering variety of claims from different manufacturers. Excited chatter about le cable du jour is commonplace in todays Web salons.
Alpha-Core, Inc. has made its patented line of Goertz audio cables for almost 15 years. The company began in 1982 as a manufacturer of toroidal cores for power transformers. In 1993, Alpha-Core applied proprietary technology for laminating metal foil with dielectric materials to a flat cable design adapted by Danish engineer Ole Goertz for use as a speaker cable. Alpha-Core applies this same technology to produce a line of audio interconnects, along with cables for power-pulsed-laser systems used by US laboratories and laser manufacturers abroad.
The Goertz design philosophy holds that the ideal audio cable should contribute nothing to the signal passing through it. Alpha-Core addresses this goal by adopting a form-follows-function approach that relies on sound electrical engineering coupled with manufacturing expertise. Company founder and CEO Ulrik Poulsen explains that the design approach for Goertz speaker cables " is first to lower the inductance as far as possible in order to eliminate high-end roll-off and then to eliminate distortion due to reflections caused by impedance mismatch." Alpha-Core achieves results across different implementations by making cables that use flat, thin conductors laminated with a micro-thin dielectric and sandwiched together.
With its flat, stacked conductors in close proximity, the Goertz design offers an optimal geometry for achieving low inductance. Alternating current in a wire is associated to a magnetic field that expands and contracts around the conductor according to the changing positive and negative character of the AC waveform. As this magnetic field rises and falls, it can generate current in the opposite direction of the original current and thus impede its flow. The amount of this self-induced back current increases with faster rates of AC polarity change and can result in a roll-off of higher-frequency signals. Thanks to its thin dielectric and flat topology, the Alpha-Core conductor that returns the signal in the opposite direction is in extremely close proximity to the hot conductor. The signal polarity of the return is the opposite of the hot, and thus the magnetic fields of each cancel out or mitigate the self-inductance of the other.
The MI 2 speaker cables I received for review are made from 99.99%-pure oxygen-free copper (OFC). Alpha-Core also makes a solid-silver version, and the geometry is the same for both. The twin copper conductors of the MI 2 are 0.75" wide, 0.010" thick, and each is sheathed in a virgin PFTE Teflon dielectric that is only 0.0051" thick. The conductor cross-section approximates 10 AWG. Alpha-Core describes the conductors packaged in dielectric as "thick as a penny." The review samples came terminated with solid-silver spade lugs. Rhodium spades, bananas, or pin terminations are available at slightly lower cost. A six-foot length of MI 2 terminated with silver spades retails for $187 USD.
Alpha-Core claims that MI 2 exhibits "the lowest inductance in the business," measured at 6 nanohenrys per foot, and they cite the cables characteristic impedance at 2.5 ohms. Because of this low characteristic impedance, Ulrik Poulsen notes: "Reflection spikes are effectively blocked by a near [impedance] match at either the source or the load. The match does not have to be exact -- it is our experience that a single-digit impedance works equally well with 4-ohm or 8-ohm drivers."
While were reaching the outer limits of my technical understanding, a little research reveals the characteristic impedance of a cable is equal to the square root of the ratio of its inductance divided by its capacitance. In Alpha-Core cables, the cost of low inductance and low characteristic impedance is a relatively higher capacitance -- the MI 2s are specified at 0.95 nanofarads per foot. There is nothing inherently wrong with higher capacitance, although high-capacitance speaker cables may require more current to keep the cable charged during voltage shifts.
Other cable manufacturers may take a different tack by trading higher inductance for lower capacitance, or attempting to achieve what they believe is a proper balance of tradeoffs. Some will argue that the ideal cable has zero capacitance, zero inductance and zero resistance; nonetheless, all physical implementations are faced with the exigencies of the relationships between electrical properties and the variables of conductor materials. Part of the fun of audio cables is the wide array of different offerings, each a product of the designer's art, each hoping to strike that synergistic match in your system.
Alpha-Core notes that a small percentage of high-bandwidth amplifiers may oscillate into a low-impedance load. This is not a product of poor amp design, but may happen when very long runs of high-capacitance cables are used. If you run into this scenario, the company provides (at no charge) what they call "R/C links" -- a resistor and capacitor wired in series, also called a Zobel network. This fits across speaker terminals and compensates for the low impedance seen by the amplifier. I had no need for the R/C links in my system, as the MI 2s alone were a good electrical match between my 4-ohm speakers and my amps with their 2.5-ohm output impedance.
Along with the MI 2 speaker cables, Alpha-Core sent several pairs of the latest solid-silver Triode Quartz (TQ 2) interconnects, priced at $187 for a one-meter RCA terminated pair. A similar version made from oxygen-free copper is also available. The interconnects geometry is similar to that of the speaker cable: very thin flat conductors stacked in close proximity. The TQ 2 features narrow 21-AWG silver foil strips sandwiched on either side of a 99.99%-pure copper ground plane -- effectively a reverse stripline transmission design. The conductors are a mere 50 microns thick and the dielectric bonded to them is microscopically thin (0.0012") polyester terepthalate (PET). A sturdy clear PVC jacket protects the bundle of thin wire strips.
When the outer PVC jacket is extruded, the TQ 2s foil conductors are twisted or purled. This makes what otherwise would be a nearly unmanageable thin foil cable into one that is very easy to handle. Alpha-Core suggests the purling and the stripline-type geometry minimize interference from external magnetic fields and aid in RF rejection. The geometry of the TQ 2 yields low inductance benefits similar to those found in the MI 2 speaker cable. The ultra-thin polyester terepthalate lamination should reduce dielectric absorption and minimize the static that comes from movement of the cable components themselves (triboelectric noise), resulting in shorter settling time when the cables are moved. According to Alpha-Core, the capacitance of the TQ 2 is 50 picofarads per foot, inductance measures at 27 nanohenrys per foot, and impedance is 24 ohms.
Termination for the review pairs was black chrome RCAs with 24K gold-plated contacts and internal machined Teflon insulation. XLR connectors are also available. One of the thin silver conductors is colored blue, and this alternating with the reflective silver wire inside the clear insulator made the cables look like sparkling rope lights in my listening room.
My analog front-end consists of a Transfiguration Orpheus moving-coil cartridge aligned on an SME V tonearm mounted to a Teres 320 turntable. Thoroughly enchanted with Audio Research Corporations PH7 phono preamplifier, I purchased the unit I reviewed a few months ago. The SME tonearm connects to the PH7 via an antique FMS Blue II tonearm cable. Digital Red Book, DVD-A, and SACD playback comes from the excellent Ayre C-5xe multi-format player.
The Ayre C-5xe and PH7 send their signals to a Conrad-Johnson ACT2 line-stage preamp, which drives Atma-Sphere MA-1 Mk III mono amplifiers. These power Audio Physic Avanti Century speakers positioned in a classic nearfield setup. Ulrik Poulsen commented that the Goertz MI 2 speaker cable is arguably the best possible Alpha-Core choice for this amp/speaker combination.
The C-5xe and PH7 connect to the ACT2 with one-meter runs of Shunyata Researchs Altair Helix interconnect. From the ACT2 to Atma-Sphere amps I use three meters of Shunyatas top-of-the-line Antares Helix interconnect. All terminations are single-ended RCAs. Six-foot runs of spade-terminated Shunyata Andromeda Helix speaker cables connect amps and speakers.
All components except the PH7 receive electricity via a Shunyata Research Python Helix Alpha or Taipan Helix Alpha power cords. And all of these plug into a Shunyata Hydra Model-8 power conditioner that gets wall current via a Python Helix Alpha power cord.
Like many audiophiles, Im a bit of a tweaker and pay close attention to cable dressing. In what can sometimes be a rat's nest of wires behind the equipment rack, I use small Styrofoam blocks to keep cables separated at their inputs and in the middle of their runs. If wires must cross one another, I try to keep them separated and at a 90-degree angle to one another. For speaker cables and interconnects from preamp to amps, I raise all cables off the floor with small tripods made from chopsticks wrapped with a rubber band. Connectors are wiped with residue-free Kontak cleaner before installation, and every six months all cables gets re-cleaned to remove any oxidation that might form a barrier to signal integrity. The accumulated improvement from this attention to detail is small but noticeable.
Starting out, I was curious about break-in time. Some manufacturers claim their cables need hundreds of hours to reach optimal performance. It was refreshing to hear Ulrik Poulsen claim the minute amounts of active dielectric in Alpha-Core cables mean very short, if any, break-in. "I would say what you hear right out of the box is what you get," he commented. My experience was slightly different. I found the MI 2 speaker cables changed very little over the review period, but it took the TQ 2 some time to reach consistent performance.
Technical specifications may help winnow choices, but sonic assessment only comes from listening. I first listened to an all-TQ 2-cabled setup, then to the MI 2 speaker cables, patiently swapping cables in and out while giving each time to settle in. Finally, I tried an all Alpha-Core system.
Listening through wires
I started taking notes with all the TQ 2 interconnects in place. On first impression, music through the silver TQ 2s evinced a nice facility for microdynamic detail along with very impressive soundstage depth and width. On the "Main Title" from Dave Grusins Havana soundtrack CD [GRP Records GRD-2003] instruments emerged one by one from different depths and positions across the soundstage, gradually blending together to form a rich, dimensional Latin tapestry of percussion, guitar, and brass. Midrange detail was very good; I heard the faint slide of Lee Ritenours fingers along his guitars strings.
Like night in Havana, each note hung with resonance in thick tropical air. Coupled with a deep soundstage, the effect was a large-grained three-dimensional pointillist picture with a wee bit of emphasis on the dots -- analogous to a sonic digital photograph with too much sharpness on the black spaces between instruments. Lower-midrange and bass lacked a bit of weight, and Arturo Sandovals trumpet sounded slightly incisive without the rich glow of burnished brass. Switching to my analog system, I played "Caroling, Caroling" from Reference Recordings Star of Wonder [Reference Recordings RR-21], an arrangement performed entirely with hand bells by the San Francisco Ringmasters. The pointillistic resonance was much fainter -- more picture than dots -- from an analog source, although there was still a teeny bit of hardness and a slight lack of brassy sweetness from the strike of clappers on bells. I figured the TQ 2 could use a little break-in time.
Over the next few weeks, I played my system casually for several hours a day with the TQ 2s in place. They evolved during that time, and I stopped hearing changes at roughly the 40-hour mark. Backgrounds became darker, smoother and more coherent. The air around instruments no longer spread across the entire soundstage as instrumental outlines came into sharper focus. "Much better," say my notes. "They just needed a little time to settle in."
I listened to Claudio Abbado take the Berlin Philharmonic and Rundfunkchor through Brahms Nšnie, a big beautiful choral piece based on Schillers romantic poem about Beauty ephemeral and yearning unattained [Deutsche Grammophon 435 683-2]. The TQ 2s did nothing to inhibit my systems penetration of Brahms dense orchestration as they laid out both inner detail and separation among performers, even when choir and orchestra were going at it together.
True to early listening, I found the abiding strengths of the TQ 2 interconnects in their ability to deliver detail and dynamics with delicacy or power. They offered a big, open soundstage if it was present on the recording, one that was consistently exemplary in height, width, and depth. These cables are not shy on pacing and rhythmic control; music flowed with spontaneous vivacity. Clattering castanets had bite and snap as Fruhbeck de Burgos baton propelled the New Philharmonia Orchestra from Castile to Cordoba in Albenizs Suite Espanola [Decca/Classic Records 6355] -- an evocative journey across eight Spanish cities. It was easy to hear the Transfiguration Orpheus and PH7 reach into the corners of the soundstage to yield defined instrumental outlines and back-wall reflections. The initial attack of plucked cellos and basses was excellent in the Moorish Granada movement, as were the delicate pizzicato violins.
With TQ 2s connecting source, preamp, and amps, my listening notes describe a bated timbral lightness on brass, winds, and triangles. Violins had nice frequency extension though they lacked a touch of richness and bloom. I heard more emphasis on the fundamental, with diminished overtones in the higher octaves. The opening oboe on Nšnie emphasized attack over mid-tone development. There was neither harshness nor glare, though harmonic textures were less densely woven from the glockenspiel, alto flute, and upper-midrange strings on the Albeniz piece.
From start to finish, the MI 2 speaker cables were consistent performers. Across all combination of interconnects I threw at them, their character never wavered. They did not intrude; they did not say, "Hey look what I can do." They brought no sonic baggage. The MI 2s simply didnt draw attention to themselves -- they got out of the way -- and that in my book is high praise for any audio product. While the absence of vice may be virtue enough, there are some things that the MI 2s did well.
The proper presentation of pace and timing is key for musical flow and vivacity. From tender languor to shake your booty, when the right signals arrive at the right time, the musical performance (and not the audio component) sets the mood. With the MI 2s in place, my feet were bopping to the slick, pulsing techno beat of "Atom Bomb" and "Kitten Moon," as Flukes Risotto [Astralwerks 6224] rocked my listening room. The MI 2s got rhythm. Leading edges from synthesizer, bass, and drum machine were crisp and punchy. Reverberated electronic tones and vocals "beamed from Mars through your fillings" popped in and out, clear and clean from different heights and depths, often appearing several feet outside the speakers.
The MI 2s easily conveyed the steady confidence of Peter Maags tempos as he and the London Symphony perfectly captured the movement of rolling waves from Mendelssohns Fingals Cave [Decca/Speakers Corner 2246-45]. Hear the propulsive effect of Maags conducting as he drives the orchestra, ceaselessly, rhythmically, through the score. From swell to trough, loud to soft, large- and small-scale dynamic contrasts were excellent. I really like components that dont impose themselves upon the music. With the Goertz speaker cables in place, I sensed no glare, etch, or leanness at any point across the frequencies. Highs were smooth and open, and strings had realistic tone. As music flowed from amps to speakers, the MI 2s appeared to leave no mark. When my listening notes start describing music and not review products, Im hearing the good stuff -- and thats where the MI 2 speaker cables took me.
Some may feel a comparison of cables from Alpha-Core and Shunyata Research a bit disproportional given their difference in cost. A six-foot run of Shunyatas Andromeda Helix speaker cables goes for $1495, while one-meter pairs of the Antares Helix and Altair Helix interconnects go for $1995 and $995 respectively. I found the comparison educational, however. Here are different designs, each bound by the same physical properties of electricity and materials. Each adopts strikingly different implementations in construction and geometry to meet the designer's goals -- and, yes, at different price points.
Alpha-Core cables are flat, solid copper or silver strips sheathed in micro-thin dielectric and placed in extremely close proximity to one another. Shunyata builds cables from multiple strands of ultra-high-purity copper hand woven into a patented geometry of counter-rotating braids around a hollow core. Each designer reduces inductance by placing conductors to self-cancel magnetic fields. The inductance of the Alpha-Core cables is considerably lower, while the wide separation and 90-degree crossing angle of the Shunyata Helix conductors yield a cable much lower in capacitance.
Do these differences in materials and construction help account for differences in sound? Of course they do. Both Alpha-Core and Shunyata interconnects presented an excellent soundstage with nice layering front to back. On "Stimela," a live cut from Hugh Masekelas Hope [Wordly Triloka 7203-2], it was easy to discern the position of the musicians onstage relative to the audience. With the Altair and Antares in place, Masekela himself was a touch more dimensional, more separated from the band, as the performers outlines had slightly better focus. Transients through the TQ 2s were edge-quick on the attack from cymbals and bass guitar, whereas the Shunyata interconnects sounded less incisive and a bit more at ease with themselves.
Music evinced a touch of lightness through the TQ 2, a coolish tilt in the upper mids and highs, especially on the flugelhorn and cowbell. By direct contrast, the Shunyatas had the barest breath of warmth. While I heard these relative differences, both interconnects were close to tonal neutrality. Likewise, both communicated detail well without spotlighting small background sounds from the audience and musicians. By disclosing more harmonic detail, the Altair and Antares presented instruments and voices with realistic timbres from mid-tone through decay. Here, their clarity and tonal depth were markedly superior to that of the TQ 2 and through them music played with a relaxed naturalness. Rhythm and pace were equally good from both brands, and I heard no evidence of sluggishness in the midbass and below.
While the MI 2 speaker cables compared nicely with the Shunyata Andromeda, the latter simply offered more of what both did well. Each delivered a deep, high soundstage that, based on recording, sometimes extended beyond my speakers. Listening to Brahms Nšnie through the Shunyata cables, the large mass of musicians and choristers were more individually separated and focused farther back into the stage. Dynamic vocals from the chorus carried without sibilance. The Shunyata cables parsed upper-octave strings with a touch more bloom, though both cables extended well without glare or thinness. Low-bass articulation was clear and taut from each, though the Andromeda went slightly deeper with denser timbral information that distinguishes a bass clarinet from a contrabassoon. Indeed, across all frequencies, the Andromeda reflected musics rich tonal palette to reveal subtle note bendings and inflections. Throughout the comparison, the MI 2 performed where it counts with ťlan: macro- and microdynamic contrasts, timing, and soundstaging belied cost differences between the brands.
One difference I may not have noticed without direct A/B comparison was the Andromedas ultra-black background -- a depth of absence, if you will -- that lent focus and dimension. Once I understood this difference, I went back to the Shunyata interconnects, and, yep, it's there too. The Shunyata cables were smoother and removed a hint of gauze I previously had not realized was present. This may account for their overall greater transparency, richer tonality, and refined airiness in the treble and upper midrange.
Be that as it may, the MI 2 did not disappoint. From highs to lows, they stayed within themselves coherent and balanced. The presentation of music through them was convincingly realistic. And they cost far less than a full-Shunyata set. While they do not match the harmonic realism and clarity of the Shunyata cables, I am impressed with how much Alpha-Core does deliver for a fraction of the cost.
High-end audio may be the poster child for the law of diminishing returns. Some folks will think $200 interconnects or speaker cables are too expensive, and others will insist high fidelity requires high cost. But dont dismiss Alpha-Core Goertz cables because of their prices nor overlook them because you think you should pay more. Judge them on their performance in your system, and then assay their value. The silver TQ 2 may find a natural home in systems that could use the right touch of speed and detail. I especially commend the MI 2 speaker cables to your attention. Their non-intrusive mien and faithfulness to musics fundamental character should yield consistent results across a wide variety of speakers and amps.
As always, listen for yourself. You may find that the solid construction and quality performance of Alpha-Core cables make them a true high-end bargain.
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