Positive Feedback ISSUE 69
Sapphire Reference Speaker Cables - with an Interview of Cable-'Guru' Dana Robbins
as reviewed by John Zurek
I remember my first class in basic DC/AC circuitry. We learned Ohm's law, designed and bread boarded circuits, did a lot of trouble shooting, and spent what seemed like way too much time documenting our designs and results. After you complete a few labs you find out quickly there are some things that can seriously affect the design of your circuit that looks great on paper. The quality and tolerance of the components like the resistors and capacitors you use are certainly a factor. But also very germane are the huge problems that unintentional resistance (R), parasitic capacitance (C), and inductance (L) may have on your circuit or system. This can be especially problematic when using conductors of any length. I always wondered why most cable manufacturers never mention mitigating the crucial effects of R, L, and C in speaker cables and interconnects. After all, they are part of the circuit that connects your components, amp and speakers and could cause some very unfortunate problems.
Enter Dana Robbins and his company, DanaCable, which strives to eliminate the effects of R, L, and C on the free flow of audio signals by using a back to basics approach. The design, material, and unique construction of these cables result in very low R, C, and L measurements as compared to other cables. Dana is a degreed electrical engineer with 35 yrs experience; a cable and tube circuit guru, and is also a die-hard analog-loving audiophile with an outstanding ear.
According to Dana: "Cables cannot improve the sound of your system, but can certainly degrade it. A poorly designed cable can make reproduced music sound veiled and lifeless. We choose to get back to basics instead of going exotic in our approach. While others seek new, but often un-proven, materials, we strongly believe that when it comes to cables, more copper is better. For audio signal transport, copper is a tried and true and very cost effective material. We put more than 10,000 strands of Oxygen Free Copper (OFC) in our 8-weave Sapphire speaker cables, reducing R to 4 milliohms in a 2.0 meter pair. We construct our cables with a patent-pending technique to reduce L and C to a minimum, which ensures any effect they might have is well outside the audio range. Our speaker cables measure as low as 1.6uH in inductance and 270pF in capacitance for a 2.5 meter run. Besides holding the wires together, the weaving makes for a very flexible cable that audiophiles find very easy to install, as compared with large, stiff, and cumbersome cables. Lastly, we use high-quality connectors to terminate the cables to ensure the best possible performance." All DanaCable products are designed and handcrafted in the US.
My first exposure to DanaCables came when I reviewed the Gingko ClaraVu 7™ Modular Loudspeaker System. When Dana Robbins arrived at my place to set up the Gingkos (DanaCable is part of the Gingko Audio family of products) he came armed with a prototype of both his Sapphire speaker cable and interconnects. The first thing you notice is the very unusual weave design of the Sapphire speaker cable - quite a deviation from the norm. When I got familiar with the ClaraVu 7's character I swapped in the prototype speaker cables. Hitting play on my Ayre CX-7eMP let me experience a true transformation. One of the very few that have ever really come my way in audio. I experienced what has become the most important characteristic of reproduced music to me.
I felt the music singing to me in a way it never had before in my system and room. These unusual woven cables had quite an effect on the music and my perception of it. To say I was impressed is understating. When I rotated in the prototype interconnects the effects were even more pronounced. I stopped trying to hear and describe every nuance, which although were more prominent, became less and less important as parts as the whole of the music became really coherent.
I've been using the Sapphire Reference speaker cable for a few months now with a few different speakers. First with the awesome Gingko ClaraVu 7™, followed by the overachieving Tekton Pendragon, and lately with my Merlin VSM-MMis. The Sapphire Reference speaker cable was swapped with the original Sapphire prototypes during the Gingko Speaker review. They are at the top of the food chain of the DanaCable Speaker Cables line, with the Sapphire (also an 8-weave) and the Onyx (a 4-weave) rounding out the lineup. The Sapphire Reference speaker cables features include an 8-weave direct connection, Eight 8 awg wires per cable (no transition blocks), 10K+ strands of OFC per cable pair, with Bi-wire capability standard. Lots of copper makes the Sapphire Reference heavy while the distinct weave pattern leaves a rasta-like impression. Although weighty, they are easy to use and place because they are very flexible, and tend to stay put once placed. Dana prefers locking bananas, but spades are also available.
The Sapphire interconnect used for this review falls in a slightly different category, and sits in the middle of the DanaCable hierarchy flanked by the Onyx on the lower end and the Sapphire Reference interconnect on the top tier.
The Sapphire features premium gold-plated locking connectors for maximum signal transfer, high performance dielectric core for low capacitance, and a served shield with PVC inner jacket and added outer jacket for increased cable protection.
When I first listened to the Sapphire prototypes on my system with the ClaraVu 7™ Modular Loudspeaker System this was my reaction:
"After sampling a wide variety of discs over a week or so, I decided to insert the DanaCable speaker wires. All I can say is Wow. With the 8-weave DanaCable in the loop the Gingkos sprang to life. I was all of a sudden moving with the music. Involved
Glare removed, but sparkle added, and improved imaging cues. There was a palpable, natural flow and ease. Honestly, I've never been so moved by changing out one set of cables. My curiosity was totally piqued, so I pulled my interconnects out, and went with an all-DanaCable system. The last bit of glare vanished, and everything was more resolving, yet at the same time feeling smoother with an improved sense of pace."
The Sapphires really opened a new and exiting portal to the music, and also kicked up the wow factor like no other component I've reviewed. When I looked up the definition of "wow" Google came back with "expressing astonishment or admiration." That's about right. The music just seemed to flow out of the speakers, never strained. Details did not need to be extracted; they all existed on their own level and revealed themselves without effort. What was happening here? I first noticed the mid bass. Not only was it much more present, but much better defined, and quick, with no lingering effects. The low bass was also transformed. Deeper, faster, with more powerful impact, this was some of the best low bass I've heard from non-powered speakers. It was especially visceral without that bass aftertaste that many systems exhibit. The balance became more pleasing, less detached. The presentation of rest of the audio spectrum also changed for the better. Details in the mid and high ranges that were (who knew it?) previously masked now seemed to sing. Maybe they were hiding in that previously bad aftertaste? I heard more natural fast attacks and smoother, more refined delays of notes and voices. The entire soundstage blossomed with airy harmonic nuance, creating an incredibly alive musical experience, with a yin/yang balance of macro and micro dynamics. The Sapphires simply and easily unlocked a wealth of hidden potential in my system.
The Sapphire Reference does not lean in any direction. It seems perfectly neutral without the clinical characteristics that so many who claim neutrality are plagued with. It will uncover and deliver whatever is hiding in your recordings. For me that meant more pleasure, a better understanding of the music, and a desire to listen more whether the source was analog or some form of digital. The weave works.
The DanaCable Sapphire Reference is the essence of what a positive audio experience should be. First and foremost, they exhibited outstanding balance and musical strengths in every respect. Second, and maybe more important, was the feel. The sum of the ease, the flow, and impact made my system sing. Although heavy with an unusual weave pattern, they were easy to use, and come with a 30-day money-back return. I do predict that once you try them the 30 days will fly by, and if anything you'll become more enamored, like I have. The weave stays right here.
Dana Robbins has combined solid engineering expertise with high quality materials, common sense design, and absolute quality control to produce the Sapphire Reference, a speaker cable that I believe will compete favorably with any existing exotic design. My system simply gives me more pleasure than ever before when I use the DanaCable Sapphire References to complete the circuit between my power amp and my speakers. Remember: "Without deviation from the norm, progress is not possible" – FZ. Very highly recommended. John Zurek
DanaCable Sapphire Reference Speaker
Interview with Dana Robbins
John Zurek: With so many cable companies already established, what made you decide to go into the audio cable business?
Dana Robbins: DanaCable grew out of a problem solving session with my own reference system. I was always looking for improvements, a bit tighter bass response, more depth, better soundstage, etc. I was really into amplifier topologies, especially tube amps. I had been making design changes to my 845 SET tube amplifiers, and was seeing improved measurements on the bench. But when I would put the amps back into my system I wasn't hearing the improvements. So, I started measuring everything and eventually found that my speaker cable was the limiting factor.
JZ: Why is your speaker cable a deviation from the norm?
DR: The big difference is the ultra-low resistance of DanaCable speaker cable. At ~4.0 milliohms for a 2 meter length it is among the lowest in the industry. As a passive device a speaker cable has only three electrical parameters, R (resistance), L (inductance) and C (capacitance). Since the audio frequency spectrum tops out at 20KHz, R is the dominating factor here. That is not to say that L and C have no effect, we just have to manage their values to ensure that their first order affects are well above the audio spectrum.
JZ: Why is low resistance for a speaker cable so important?
DR: It's all about the damping factor, which is very important from the smallest flea powered SET systems, through 1 kilowatt solid-state systems and beyond. A normal voice coil driver in a speaker system is a motor/generator. By that I mean if we put an electrical signal into a driver it moves (like a linear motor) producing sound, and if with no signal applied the cone of the driver also moves, it creates an electrical signal (produces energy like a linear generator, this how a microphone works).
JZ: Why would the cone move on its own with no signal present?
DR: Most people don't understand the generator part, and don't fully realize how it negatively affects the reproduced music. Just like a child on a swing that keeps moving back and forth after you have stopped pushing, a speaker cone has mass and momentum too. Even when the signal stops the cone will continue to move until its stored energy is dissipated, which usually takes a few back and forth cycles. This can be seen in tone burst tests typically performed on loudspeakers. The worst offender in a loudspeaker system is usually the woofer, because it is the largest driver with the most mass.
JZ: How exactly does the damping factor relate to this?
DR: Damping factor is defined as the ratio of the electrical load impedance (say an 8 ohm speaker) to the source impedance (our amplifier). Take for instance an amplifier with an advertised damping factor (d.f.) of 100, referenced to an 8 ohm load. This means that the amplifiers impedance at its output is 8/100 = 0.08 ohms. So when the bass note stops and the woofer continues to move, the electrical energy developed by the woofer is then absorbed by the amplifier through this low output impedance. When this happens the amplifier is effectively applying the electrical brakes to the woofer. The lower the impedance the better and quicker job it can do stopping the movement of the woofer. In theory the higher the damping factor the better the control of the woofer. So the reproduced music will truer to the original source, but there are limits to this.
JZ: How does the resistance of the speaker cable play into this?
DR: Speaker cable resistance is in series with your amp and your speakers. This added resistance in the speaker cable degrades the damping factor.
Here is a damping factor example with average 16 awg speaker cable:
The actual d.f. for the system has now been reduced from 100 to 50. So the average 16 awg speaker cable has degraded the d.f. by a whopping 50%!
Now, the same example but with DanaCable speaker cable:
With the DanaCable the actual d.f. for the system has now been reduced from 100 to 95.2. So the DanaCable has degraded the d.f. by less than 5%, ten times less than the effect of the 16 awg cable (5% vs. 50%).
JZ: OK, the DanaCable shows a major improvement, but don't most audiophiles use heavier wire than 16 awg?
DR: I chose the 16 awg example because it makes the math straight forward. Obviously for heavier gauge wires the degradation is less, but even for 10 awg cable the d.f, would drop from 100 to about 80, a 20% reduction. Of course this is assuming that the connectors used don't add significant resistance, which when we are talking milliohms is very detrimental. DanaCable uses special locking connectors to ensure mating resistances are kept low to take advantage of the low resistance cable.
JZ: So... how does keeping the damping factor high translate to better sound?
DR: As you know music is not a steady state tone, and by it's own nature is a very complex and dynamic waveform. For instance when someone hits the bass drum the sound is a burst of energy that starts and stops every time the drum is hit. When drivers in a loudspeaker are not being faithful to the signal dynamics that they are being fed by the amplifier, the sound is inaccurate. Some describe this as a "muddy" or "congested" sound, where individual instruments and voices are not as distinct as they should be. With the DanaCable you will hear much tighter, well defined bass and mid-bass. This then opens up the midrange and high-end clarity because the bass and mid-bass overhang is gone, so there is no masking of the finer details in the music. Listeners have reported a deeper, wider and a better defined soundstage as well.
JZ: Why do you weave the cable?
DR: First and foremost the weaving allows us to control the inductance and capacitance as mentioned earlier. We have a patent pending on this so I can't go into too much detail. But I will tell you that construction layout that minimizes inductance tends to increase capacitance, and vice versa, so what we do is strike a balance between the two which gives us values that put the first order effects above the audio band and do no harm to the music. Secondly, the weaving allows us to have 8 large cables and maintain flexibility for such a large cable. If they were all in tied into a round bundle it would create way too stiff a cable.
JZ: What types of music did you listen to while developing the weave concept? Anything in particular you used for evaluation?
DR: Nothing in particular, I like most styles of music. I generally listen to a lot of jazz, and have a weakness for female vocalists.
JZ: Most cable companies tout exotic metallurgy composition or complex theories of dielectric absorption to achieve better performance. Why did you go with a different, simpler approach?
JZ: I know you also have interconnects available, but any plans for power cords or digital cables?
DR: DanaCable interconnects and digital cables are available now, but still in the process of patent development, so I will hold off on technical details. We also have power cords and digital cables in development. We'll be at the 2013 RMAF in the Gingko room offering the DanaCable Speaker Cable Shootout and performing a demo of damping factor and how it affects sound quality: http://www.gingkoaudio.com/index.html
JZ: Thanks Dana!