Review: Heresy with a Nordost Heimdall 2 ethernet cable

It has bothered me a bit and it took some thinking on what to do with the Nordost Heimdall 2 ethernet cables. The problem? They make a huge difference over my Supra Cat8 cables, let alone the generic Cat6a I was using before the Supra ones. And if someone dares to say “ethernet cables make a difference in sound reproduction” he will immediately get labeled as a fool, a crazy, or even worse, an audiophile.

The story goes back a few months, I was asked if I would be interested in “auditioning” some ethernet cables. The answer was, sure, as long as I don’t have to write a rave if they make zero difference over my Cat8 cables.


No such thing as Cat7 or Cat8 ethernet without the use of specialized connectors such as GG45  or TERA. The so-called “audiophile” ethernet cables who utilize plain RJ45 connectors don’t meet such criteria but they still proclaim themselves as Cat7 or 8 because, and this is my best possible explanation, the bandwidth they allow through meets the required specifications which are 600MHz and 2GHz for the 7 and 8 respectively, far above the audio requirements for even the heaviest DSD or DXD files.

Da system

My digital front end consists of a Synology NAS in raid0 configuration, a TP Link Archer router with linear power supply, an Odroid C2 based Linux streamer with linear power supply running Archphile OS and the Rockna Wavedream DAC (the first generation with the MSB Platinum modules) connected to the streamer with the Das Klang Richter USB cable. I normally run 11m of ethernet cable from the router to the streamer divided into two patches, the long one was a custom-built from Nordost as no 10m Heimdall 2 is readily available, then a Baaske medical grade network isolator placed on the last meter takes care of possible noise before entering the streamer’s gigabit input. Same 10 & 1m lengths were also purchased a few years back from a no name brand, then when Supra announced their Cat8 cables I moved on and got them as a “final” solution. Supra is a serious company, making value-for-the-money cables that would guarantee my peace of mind for years to come.

For test purposes, and since I wanted to eliminate as many bias factors as possible, the isolation filter and last meter of cable were taken out of the chain, so what I used was the vanilla plain Cat6a, the Supra Cat8 and the Nordost Heimdall 2, all running the exact same 10m from the TP Link router straight to the Odroid streamer.

As few of you will be familiar with the Odroid C2, this is, to the best of my knowledge, the most sophisticated single-board computer out there, with specs far above the Raspberry Pi 3, Udoo or Cubox. It packs a 1.5Ghz, 64bit, quad core ARM Cortex CPU, 2Gbyte DDR3 SDRAM, the OS runs on a blazing fast eMMC5.0 HS400 Flash Storage and it also has separate bus controllers for the Gigabit ethernet and the USB ports. There are a few available OS systems but my choice since back the days of Rpi2 remains Archphile, a stripped to the bone Archlinux based operating system. I run Archphile with the largest possible buffer size and always use the latest kernel available. The WiFi option is permanently turned off while the entire system, including the streamer, is powered from a dedicated power line coming straight from one of the three phases, used exclusively for that unique line. Not much left in chance.

Just to make sure it wasn’t something to do with my usual hardware additional tests were performed with the Auralic Aries femto clock & linear PSU streamer along with the latest Mytek Brooklyn DAC+. As a back up USB cable I use the dirty cheap Belkin Gold, which remains an excellent entry level proposition but comes nowhere close to my Das Klang Richter.


And no matter how you put it, no matter what the rest of the hardware was, there is a clearly audible difference between the Supra Cat8 and the Nordost Hemdall 2 Cat7 cables.

Trolls, unleash Hell

But give me a second first. The differences are so big in terms of soundstage depth and width, detail and air among the instruments that far exceeded my expectations. I am not sure where to attribute the differences and honestly I don’t even care that much, they are there. I went on and called some friends for a listen, not just some seasoned audiophiles or what some would call “believers”, I also invited my geekiest, DIYers, “bits are bits” guys I could think. They tried to explain the reason for the obvious decline in soundstage dimensions with the Cat8 cable, they inspected the Metz connectors on the Norodst cable and went on telling me that it probably is a matter of noise, grounding and shielding. Going through the net I stumbled upon a simple but well written page on eBay, where the author explains what are the fundamental differences between the various ethernet cables. The 6a must have grounded connectors, the 7 are fully shielded and each of the shielding layers must be grounded.

The other point that got me thinking is the fact that higher specs guarantee transmission for greater lengths, as ethernet cables are prone in picking interference.

For category 6a cables running at 10 Gbps speeds, 55 meters is the maximum allowable length, and even this length is only allowed in very good alien crosstalk conditions, or areas of low interference, such as when the cable is located far away from other cables that could cause interference

Could that be a logical explanation on why such differences exist? Could it be attributed to the thicker solid copper conductors vs the stranded and thinner ones of the Supra? Again, I don’t give a hoot. Not to mention that on paper the Supra cables rated @Cat8 are superior to the Nordost Cat7. Unfortunately, that is true only on paper, sound-wise there is an abyss between them. The price difference is also significant, the first meter of the Nordost comes at $700 while the Supra sells for approximately $50/m.

A heresy? Probably. A huge step up for my system? Most definitely so.

Now its time to face the music Hell. Feel free to bring it … as long as you have a first-hand experience.