Single Crystal Evaluation
The Harmonic Technology Entry Level Line Featuring Precision-Link, Cyber-Link, Pro AC-II, and Melody Line
Jason Serinus
4 January 2000


(2) $129/one-meter RCA-terminated Precision-Link interconnects.
(2) $99 one-meter/BNC-terminated Cyber-Link Copper digital interconnects.
(1) $250 8-ft. pair of Melody line 12 AWG Single Crystal speaker cables.
(6) $170 Pro-ACII A/C Power Cords (2 Meter Hubbell Male plug).
Harmonic Technology,
13100 Kirkham Way Unit 212,
Poway, CA 92064, USA,
POWA TEL: (858) 486-8386,
FAX: (858) 486-6633

"Depending upon your components’ individual strengths and weaknesses, and what happens when you connect them in sequence, the Harmonic Technology Pro AC-II power cord might prove just what you need."

When I bought my first entry-level high-end Rotel CD player over seven years ago, my dealer shocked and infuriated me by insisting that I had to spend at least $78 on his Audioquest Ruby interconnect in order to get decent sound out of the unit.

"$78 for an interconnect!" I exclaimed. "$78 for one measly meter of wire? You must be kidding."

Under protest, I took the Ruby home for audition. Exhibiting what I now realize were the first symptoms of audiophilia persemprelia, I also borrowed his more expensive Audioquest Quartz. Moreover, because I was sure he wished to gouge me out of house and home, I went to another store and borrowed an MIT interconnect that cost $49. Upon audition, the results could not be denied. The most expensive Quartz sounded the best of the lot. I ended up buying it, upset by the price, but thoroughly convinced that the quality of interconnect does make a huge difference in how much of a system’s full potential one can actually hear.

I’ve come a long way since then. The Quartz has mostly been sold, and the Audioquest that remains in my digital set-up is top-of-the-line stuff. However, I am still looking for that bargain line of cables that pulls the rug out from under the whole high-priced interconnect market.

This past September, when I had the opportunity to audition Clement’s wonderful system, he invited me to review the entry-level Harmonic Technology Precision-Link interconnects. Given my long-standing quest for the "best buy" bargain interconnect, and the positive contribution that Clement’s Harmonic Technology Pro-Silway Mk. II interconnects were presumably making to the sound of his stunning ultra high-resolution set-up, I of course said "yes."

One meter of Precision-Link interconnects retails for $129, considerably less than the $599 Nirvana SL-1 and $799 Tara Decade interconnects currently in my CD chain. Given the price and quality of my own interconnects, I asked both myself and Clement if it would it be fair for me to conduct this evaluation. Would I be so disappointed in the difference in performance that it would be in everyone’s best interest — and that includes readers — to give this review to someone who was used to listening to music through low-priced interconnects?

When I repeated this question to my Harmonic Technology contact, he was so confident in the quality of his entry-level products that he upped the ante by sending me enough entry-level interconnects, speakers cables and power cords to replace all in digital chain except those leading to my Hsu subwoofers. In addition to the two $129/meter RCA-terminated Precision-Link interconnects, I received two $99 BNC-terminated Cyber-Link Copper digital cables to replace my much-loved $600 Nirvana Transmission digital cables — cables that I chose after an extension audition in which they trounced five other brands, including the much-touted Illuminati D-60; a $250 8 ft. pair of Melody line 12 AWG Single Crystal speaker cables to replace my $3299 pair of silver AudioTruth Dragon II, and six Pro-ACII power cords, to variously replace my MIT ZII, XLO Purple, Cardas Hexlink V, PS Audio Power Link, and pair of Synergistic Master Coupler power cords.

Even before the shipment arrived, I received Harmonic Technology literature. The technical discussion of Robert Lee’s, (Former HT chief engineer) design was accompanied by many glowing testimonials. I glanced at the Table of Contents. What did I need with yet another position paper by a designer whose goal was to convince me that his design was superior to all other cable designs on the market? Everyone says this. The proof is in the listening, not the reading. So I put the literature aside, deciding to read it and share it with you only after my listening evaluations were complete.

The First Listen

The HT spokesperson told me that minimal break-in had been performed on the cables, and that they’d sound good from the start. Trusting him, I connected everything at the same time, separating cables and power cords from each other by inserting 1.5" square pieces of Styrofoam between cables that were touching. Since I had affixed Shakti On-Lines -- little devices that one fastens to cables and cords to reduce ring, lower noise, and increase the size and depth of the soundstage – on all but my digital interconnects, I removed these and placed them on the Harmonic Technology products. My digital chain, save for my Hsu subwoofers, was now totally connected by and powered through HT’s babies.

My first hit was that everything sounded too bright. An e-mail exchange revealed that the cables needed a short period to settle in. Since my experiences with other cables have revealed that manufacturers frequently underestimate the amount of time necessary for a cable to fully seat in a system, perhaps in order not to scare away potential customers, I turned on the XLO break-in tones, alternating them with full-range symphonic music, and let the music flow for days. I then demagnetized the system with the XLO disc, demagnetized a few of my favorite CDs with the Bedini Ultra-Clarifier, and began the evaluation.

I must confess to initial disappointment. Ever since I changed my amp and preamp, my system has excelled in transparency, accuracy of timbre, color, size of soundstage, and three-dimensionality. My latest improvements, the addition of the PS Audio P300 Power Plant and Power Link, and the upgrading of my Bruce Moore Companion preamp to II-C status (review forthcoming), have greatly increased my system’s reproduction of "air" and three-dimensionality, as well as its resolution, palpability, and believability. Alas, while the soundstage size remained intact with the Harmonic Technology chain in place, everything else seemed diminished. Images flattened, and various instruments and voices seemed run together without sufficient air to breathe. The midrange lost some of its fullness, as did the bass; color became more monotoned; and the black between the spaces became just a touch gray. The life and magic of a system that had frequently thrilled me (when it wasn’t driving me batty) were sadly absent.

At the same time as I was attempting to review these products, I began reviewing classical CDs for several print and web publications. Since I wanted my system sounding its best when evaluating music and sonics, I decided to return much of my system to its original state, and proceed with my Harmonic Technology evaluation in stages.

First, I replaced all the Harmonic Technology interconnects with my own, leaving only the HT power cords in the chain. Much of my old sound returned, but something was different. I still felt as if the sound was more uniform in color and a bit less lively. Not all the magic had returned.

Next, I returned all but two of my power cords to their original positions. This left Harmonic Technology cords on my Theta Gen. 5A single-ended DAC and Genesis Digital Lens. I noted the sound, and then returned my MIT-ZII cord to its usual place on the DAC. I switched back and forth a few times between HT and MIT cords while playing the same selections, and noted differences in sound. The cords were close, but the MIT, on the DAC at least, seemed a bit sweeter and had more definition, color, and bite. While the Harmonic Tech cord seemed smoother, with that smoothness seemed to come a concomitant loss of liveliness. It is this liveliness that made my system so magical to my ears.

I knew what I had to do next. Taking some deep breaths, and trying not to grit my teeth, I commenced a power cord audition procedure I had once performed several years earlier. At that time, my system’s highs had a certain irritating, tizzy quality that drove me batty. No matter how many pieces of equipment I had changed, or how many times I returned my tunable Chameleon III speakers, the problem had remained. So, at the suggestion of the irreplaceable Bob Cohen of The Cable Company, whose knowledge I consider a gift of the audio goddess, I first removed all my dedicated power cords, replaced them with the stock cords that usually come with equipment, and took a listen. The difference was immense. What ten minutes before had been a stunning, if problematic high-end system now sounded like a very good, but certainly far less expensive hi-fi set-up. (Trust me folks, good power cords make a huge difference).

"Along with the PS Audio Power Link, I would declare the Harmonic Technology Pro AC-II a Best Buy."

Then I invited a fellow audiophile over to help me. We chose one piece of equipment, my power amp, and connected, one at a time, each of what were then my five dedicated power cords. We carefully noted the differences in sound as we played the same CD tracks through each cord. Then we moved on to the preamp, and repeated the experiment. By the time we had finished listening to the last power cord, we had reached a degree of burnout intense enough to induce my friend to run out the door before we could do try the cords on any other equipment.

The experiment revealed that one of my power cords, bought used without prior audition, imbued my components with exactly the sonic characteristics that I had found so irritating in my system, and that a second, a more expensive issue from the same manufacturer, also negatively affected the sound. Two of my other cords, by XLO and MIT, were definite winners, while my (used) Cardas Hexlink V cord seemed to offer only a minor improvement over stock cords. Within a week, both offenders had been replaced by used Synergistic Master Couplers, another level of my system’s offensive sound had been eliminated, and joy returned to the Serinus household.

Now I was faced with repeating this massive experiment, this time alone. With smelling salts and oxygen on hand, and 911 programmed into auto dial, I set to work. I powered up everything through stock cords, confirmed the degradation, and then tried my different cords, first on my Pass Aleph 5 power amp (save the Hexlink V which was too short to reach), and then, a day later, on my modified Bruce Moore Companion II-C tubed preamp. Copious notes were taken.

Here is what I can say with certainty. The Synergistic Master Coupler, the most expensive cord of the lot, seemed the most solid in its presentation. It had great air, lots of color, much fullness, and the most midrange warmth and bass extension. The fabled "sound of the hall" that we reviewers love to talk about when listening to good orchestral recordings was clearly in evidence. Next in quality came the $150 PS Audio Power Link. With the greatest bite of the lot, an edge on stringed instruments and voices that might prove too much for an already-bright system, the Link delivered much focused detail, three-dimensionality and height, as well as a welcome fullness in the midrange and bass. A violin’s sound, for example, was clearly defined, rather than spread and wooly around the edges. Most importantly, the noise floor seemed lowered, with the black spaces around instruments much blacker and quieter than with most other cords. With the "sound of the hall" coming through quite clearly, I judged this cord of very high quality. [Note: This cord has been discontinued due to a lack of availability of key components. A new, beefier PS Audio Lab cord is due out before long. The PS Audio set-up sounded fab at CES; I look forward to auditioning this cord].

On the power amp at least, the Harmonic Technology Pro AC-II power cord seemed virtually as good as the PS Audio Power Link; only on the preamp, as it had done previously when connected to the DAC, did it seem to convey less color. (This suggests that different pieces of equipment work differently, and call for different interconnects and power cords in order to shine their best). Along with the now-deceased PS Audio Power Link, I would declare the Harmonic Technology Pro AC-II a Best Buy. On the power amp, I liked it better than the somewhat comparably priced MITZII and XLO Purple cords, and much more than the weakest cord in my system, the Cardas Hexlink V. (This conclusion does not negate the fact that, when the Pro AC-II replaced my two Master Couplers and one Power Link as well as my other cords, its conveyance of less color proved a disappointment.)

Because of this experiment, I would suggest readers experiment with various combinations of cords, including the Harmonic Technology Pro AC-II power cord. Depending upon your components’ individual strengths and weaknesses, and what happens when you connect them in sequence, the Harmonic Technology Pro AC-II power cord might prove just what you need.

"What I do know for certain is that they are such a good buy for the money that anyone who cannot spend much more than $250 for an 8 ft. pair of speaker cables would be foolish not to give them an audition"

For the remainder of my experiments, I returned all but one of my power cords to their usual positions. Feeling that the Harmonic Tech cord was superior to the Cardas Hexlink V that had powered my Genesis Digital Lens, I used the Harmonic Tech cord instead.

Next I replaced my AudioTruth silver Dragon II speaker cable with the Harmonic Tech Melody line 12 AWG Single Crystal copper speaker cables. Please note that there is a $3000 difference in the price of these cables, and that silver is a better conductor than copper [see technical discussion below]. Despite these differences, the Harmonic Technology Melody did a surprisingly good job. Sound was neither as full, as transparent or as extended as the Dragon II, but it was very good. How the HT Melody compares with some of the other supposed bargain-for-the-money cables on the market, such as those from DH Labs and Wireworld, I do not know. What I do know for certain is that they are such a good buy for the money that anyone who cannot spend much more than $250 for an 8 ft. pair of speaker cables would be foolish not to give them an audition. Just be sure to allow them enough time to fully seat in the system.

I was now left with evaluating the HT Precision-Link interconnects and Cyber-Link digital interconnects. The demand for CD reviews was growing, and I didn’t want to dismantle my whole digital chain one more time. Besides, I wanted to find a way to test these wires on a set-up whose price was more in line with the kind of systems that usually contain entry-level interconnects.

It just so happens that my AM/FM tuner is as entry-level as they come. This ancient pre-digital Kenwood is tuned by depressing little bars which cause a pointer to either "zzzz" up or down the frequency spectrum until it stops at something strong enough to command its attention. (That is, it zzzzs unless it gets stuck, in which case I give the tuner a moderate thump, and the pointer begins to zzzz anew). My Kenwood throws a very wide soundstage, but delivers too bright sound. (This isn’t helped by my physical location, whose imperfect FM reception does not warrant investing in a better tuner).

Usually, the Kenwood is connected to my preamp via a pair of used AudioTruth Emeralds ($275). For this experiment, I replaced them with a pair of $129 Harmonic Technology Precision-Links. I let them settle in for several days, and sat down to audition.

While I’m mainly an unamplified, classical music man, I chose the local light jazz, New Age FM station, because I thought there was a good chance that their music came directly from actual CDs and LPs, rather than from prerecorded tapes. After surviving a round of ads, I listened to somewhat musical selections by switching back and forth between the $275 Emerald, $17I Quartz, and $129 Precision Link. I assure you that I switched many, many times, determined to get as clear and unbiased a picture as possible.

The upshot was clear. The Emerald, retailing at over twice the price of the Precision Link, had a defining edge on the highs, as well as a sense of three-dimensional air and space, which conveyed more life and "realness" than the Precision Link. The softer Precision Link, on the other hand, conveyed a smoother sound that made my tuner more listenable and less fatiguing at higher volumes. The Quartz, recently discontinued, still had the conveted defining edge, but seemed thin in comparison, transmitting less sound overall than either of the other interconnects.

My conclusion? On this piece of equipment, at least, the non-fatiguing top on the entry-level Precision Link made for the most pleasant listening. It may not have conveyed all the three-dimensionality and air I desire, but for an entry-level interconnect, it is clearly a definite candidate for audition in a lower-priced soundsystem. In a system with a bright digital set-up, of which there are countless millions, it may in fact prove a best buy.

The Technology

"Harmonic Technology claims their unique purity processing contributes to realism."

The information that follows is distilled from a 15-page booklet by former Harmonic Technology engineer Robert Lee. Besides reporting that the before and after electron microscope pictures in the booklet reveal a tremendous difference between the crystal structure ordinary copper and Harmonic Technology’s single crystal copper, I cannot verify any claims made in the brochure.

Two metals conduct electricity better than all others: copper (98% conductivity) and silver (99% conductivity). Standard copper wire is usually manufactured to approximately 99.99% (4N, or 4 nine) purity; it still contains oxygen, which does not conduct electricity, plus a variety of other contaminants. Harmonic Technology, however, has pioneered an inexpensive method of refining metals to much higher levels of purity that 4N. This refining process is done in an oxygen-free atmosphere, greatly reducing the chance of long-term oxidation.

The collision of electrons with impurities in copper and silver modifies the harmonic structure of the signal, and is heard as harshness or brightness and/or veiling and dullness. Harmonic Technology claims their unique purity processing lessens this possibility, contributing to greater realism.

When copper wire is produced, thousands of crystals are inadvertently formed in the copper. These crystals form barriers which impede the natural flow of electrons, adding harshness and brightness to the sound and altering both image precision and sound stage focus. (The operative term is distortion). Approximately 500 crystal boundaries per foot are found in high-grade, oxygen-free copper wire, with as many as 1500 boundaries occurring in normal wire. Harmonic Technology provides electron microscope photographs of cross-sections of normal wire and their own Single Crystal™ OCC wires to demonstrate that there are precious few crystals in their wire.

Some other pluses of HT products: Harmonic Technology uses Teflon and air-filled polyethylene to insulate their wires, because such quality insulators do not modify the signal as do less costly insulators such as vinyl. Harmonic Technology’s Balanced Field Geometry™ reduces both inductance and capacitance to theoretical levels, allowing an almost perfect transmission-line path without alteration of the signal. Finally, HT’s connectors use Single Crystal high-purity 6N copper to provide the best transmission of detail in the signal.

Harmonic Technology’s RCA plugs terminations feature an outer locking barrel. This can be used as a "tuning" device to alter the sound of specific images within the sound stage. All joints are mechanically compressed (cold-welded) before solder (not as good a conductor of electricity as pure metals) is applied, helping create a strong bond which allows maximum conductivity of electricity.

Putting It All Together

Harmonic Technology makes an impressive line of entry-level cables and interconnects. While they have their limitations, they deliver great rewards for a relatively small investment. The Precision-Link and Cyber-Link interconnects will mate especially well with lower-priced equipment that tends toward brightness on top. For speakers that tend to dole out both bright highs and exaggerated lows, an audition of Melody 12 AWG Single Crystal speaker cables would prove wise. The Pro-ACII power cord, which represents a substantial improvement over stock cords, would again prove a good choice for certain systems. The products are complementary, and have a similar sonic signature. Given today’s prices, they are certainly great value for the money. You may find them just right for you.






















































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