How does cable design affect the audio performance of digital cables?

When you’re looking for a digital interface, cable design is of the utmost importance, but what aspects of cable design matter, and how do they affect the performance of your digital cable? There are several electrical characteristics to consider, the top four being: characteristic impedance, capacitance, shielding and transmission speed. 


Characteristic Impedance: 

When speaking about the impedance characteristic of a digital signal, it is important to note that, while you may want to focus on the cable alone, the transmission line of a digital signal starts where the RF signal is generated inside the digital source and ends where the signal is decoded inside the digital receiver. However, for the cable alone, the impedance characteristic is defined as the ratio of voltage to current at the input to an infinite transmission line. The stability of the impedance characteristic depends on several design aspects of the cable, including conductor size and geometry, insulation material and the thickness of that insulation, and connector quality and type (75 Ω for S/PDIF, 110 Ω for AES/EBU, 90 Ω for USB, and 100 Ω for UTP Ethernet cables).


Capacitance: 

In digital cables, high capacitance of a cable will slow down voltage transitions, causing an unevenness to the flat portions of a square wave. When this happens, the D/A receiver on the other end of the signal will have a harder time identifying the data transmission. Many aspects of cable design that help to minimize capacitance are the same aspects that affect the impedance: decreasing the conductor diameter, changing the conductor geometry, and using insulation with a low dielectric constant. The art of designing a high-quality digital cable is finding the balance between what needs to be done to keep capacitance low and avoiding negative impact on the characteristic impedance of the cable. 

To keep capacitance low, Nordost implements their proprietary Mono-Filament technology in their digital cable design. By intricately and uniformly wrapping single or twisted pairs of FEP Mono-Filament around each conductor before encasing them in an extruded layer of high-quality FEP, each conductor is surrounded by its own air dielectric. In decreasing the interaction of the conductor to the insulation, the signal is no longer hampered like it is in more traditional digital cable designs.


Shielding:

Whereas in analog interconnects shielding is used only to keep foreign elements away from the signal, in digital transmission, shielding both keeps external radio frequencies and electromagnetic interference away as well as keeping RF signals inside of the cable itself. When designing a digital cable, one important thing to keep in mind is the compatibility of the specialized connectors with the shielding material, as that will determine how manufacturers implement the shielding into the design. 


Transmission Speeds: 

While fast transmission speeds are always sought after in cable design, for some digital cables it is absolutely essential. USB cables, for example, must perform a digital handshake (where the signal travels from source to destination and then back in 26 nanoseconds) to work. When using a conventional design, that handshake is only possible at short lengths. Nordost USB cables, on the other hand, employ Mono-Filament technology, enhancing signal speeds so much that we are able to build cables twice the length of a standard USB cable or longer, and still achieve a reliable handshake.


For more information like this, to better understand the technical challenges of digital audio data transmission, and to know what to listen for when auditioning digital audio cables read our download, Digital Audio Cables: How Can They Make a Difference?, now!  


Dealer Spotlight: Audio Connection, Sydney

By Bjorn Bengtsson

Audio Connection was founded by Josef Riediger in 1987, born out of his passion for high-end music reproduction. When he first started, Josef had a tiny shop in a the Sydney suburb, Bankstown, and sold only a handful of products (like the legendary Gryphon, to mention one brand). After seven very successful years, he had amassed enough funds and experience to move into a much larger facility in Leichhardt, where he continued to build on his earlier success. There, Josef expanded deeper and deeper into high-end HiFi and Home Cinema. Along the way, he met some amazing people from all walks of life, and built a solid reputation throughout the industry and among customers as a real stalwart of the Australian HiFi community. 

Nordost’s journey with Audio Connection started in the early 2000’s, when then-distributor Warren Stolmack brought in some earlier Nordost products for Josef to audition. Josef was so intrigued by the results he heard with Nordost in his system that he instantly signed on as a dealer and continued to spread the word about Nordost’s performance for many years to come. 

Not long after Mr. Stolmack introduced Nordost to Audio Connection, ‘yours truly’ had the opportunity to meet with the charismatic Josef, or Joe Riediger as most people referred to him. In that meeting I remember that Joe said, in his unmistakable accent, “I don’t need to hear them again, Warren already showed me. Valhalla is the best.”  This is a statement he never would have to amend.

From then on, there have been several Nordost demonstrations made in the Leichardt facility. I have had the privilege of spending several enjoyable and memorable evenings with the ever-present customer base of engaged Australian HiFi enthusiasts. One example of such a night to remember at Audio Connection you can even read about here, thanks to Soundstage Australia’s reporting.

Sadly, Josef passed away in September 2020, one week shy of his 71st birthday. His passion for hifi is upheld by the team he left behind, comprised of Janson, Jojo, Michael, Phil, Ken, and lead by his nephew, Nigel. Between this team, there’s almost 200 years of hifi experience, most of which was spent by Josef’s side, and all sharing his passion for audio. Audio Connection has recently gone through an extensive ‘face lift’ with new, superb sounding demo rooms, filled with a full range of some of the world’s most highly regarded high-end brands, as always. Including, of course, Nordost’s entire collection, all the way up to Odin 2.


Audio Connection

Address:137 Victoria Road
Drummoyne NSW
New south Wales
NSW 2025
Phone:02 9561 0788
Fax:02 97199630
Email:sales@audioconnection.com.au
Web:www.audioconnection.com.au

Nordost Playlist – July 2021

Nordost products are designed to allow you to enjoy your favorite performances as they were intended to be heard. All of us here are passionate about great music, and want to share our passion with you. Each one of us has our own style… We listen to a wide variety of artists and genres but, in a way, we appreciate them all. We thought that we would share a few of the songs on our own personal playlists with you each month. Some may be classics, some may be brand new, some may not even be to your tastes, but we hope that there is something here for everyone.

Here are some of the songs that we will have on rotation this July.


You can now listen to our monthly playlist here:  TIDAL  | SPOTIFY  |  QOBUZ


  1. We Cannot Resist—LUMP, Laura Marling, Mike Lindsay 
  2. Bed Head—Manchester Orchestra—Bed Head 
  3. Lowdown—Boz Scaggs—Silk Degrees 
  4. Slow Mover—Angie McMahon—Salt 
  5. You & Me—Dave Matthews Band—Big Whiskey and the GrooGrux King (Expanded Edition)
  6. Comerte Entera—C. Tangana, Toquinho—Comerte Entera
  7. Somebody Help Me—Otis Brown—Southside Chicago
  8. Tip Toe—SAULT—7
  9. Dreams—Fleetwood Mac—Rumours
  10. Against The Wind—Victory—The Broken Instrument