Review: Network Acoustics tempus ethernet switch

[keithc]

Almost 20 years ago I attended a memorable lecture about traditional Chinese medicine. The speaker, a highly-published Professor Emeritus of Anesthesiology, shared incredible studies of how analgesic acupuncture is combined with hypnosis to perform heart surgery and, compared to our Western surgical lore, the patients in Asia awaken and recover quickly as if they had a minor procedure. Jeers, doubt and ridicule immediately erupted from the medical crowd as expected, especially from her U.S.-trained faculty who dismiss these observations as having no plausible scientific mechanism and can only be a placebo effect.

The speaker calmly looked at her colleagues and replied, "Well... it's not like any of us know how inhaled anesthesia work, either..."

Mic dropped.

There are things that we accept despite a lack of mechanistic explanation for how they work:
Consciousness.
Why mass causes gravitational force.
Love.
Our wives' emotions and their getting headaches at inopportune moments.
Or why some things matter in hi-end audio.

Which brings me to this review of the Network Acoustics tempus audiophile switch (their product names are all lower case). Among the spectrum of digital source components that should theoretically allow bit-perfect streaming playback, network switches receive special scrutiny for why they might affect audio quality (e.g. "switches transmit perfect error-free data in IT networks every day, so this is all snake oil"). I'll be the first to admit: I do not know why audiophile switches matter, no more than I can explain the pathophysiology behind Chinese medicine. Some folks ascribe to a reduction of electrical noise (from the switch's power supply, internal circuitry and incoming ethernet signal) transmitted to the streamer, while others opine about jitter, timing variations and blurring of square waves in audio protocols resulting in data corruption. The variation across each household's network 'noisiness' is probably also substantial. Personally I would love to see an actual analysis of how a music streamer's raw bitstream output change as a direct downstream effect of networking cables, power supplies, switches or isolation. But as someone who benefits from traditional medicine, I take a similar approach to my audio health: If it sounds good, I don't really care how it works... those who want measurement proof, please move along: you can't measure my back pain either.

Network Acoustics is a small U.K.-based company founded in 2020 by two friends, Rob Osbourne and Rich Trussell. They share an excitement about streaming music but were dissatisfied by the sound compared to their cherished analog rigs; then the Covid pandemic freed them from their day jobs (Rob a film producer and Rich an IT engineer) and they decided to pursue solutions for better digital playback. The result was the original eno ethernet filter, USB and ethernet cables, which were highly regarded and the success allowed their efforts to become a full-time endeavor. Rob describes their work as a passion project -- his excitement and energy "to make streaming their thing" is clearly evident when he describes their raison d'etre -- and their fame continued with the launch of the award-winning muon and muon pro family of products. Despite their growth, Rob and Rich oversee the final assembly and testing of each and every product, and they take pride in providing a level of customer service that they would want as consumers. They welcome audiophiles to try these products in their own systems, and increased their money back guarantee from 30 to 60 days to allow this. What can beat such a policy of assurance before investing in audio equipment?

Tempus was launched in 2023 as their exclusive and reference network switch. In asking Rob about its motivation and design philosophy, he talked about their former switch, the rubicon, which was created to complement the eno filter. However, rubicon only sold for less than one year due to supply chain challenges -- but this did not stop Rob and Rich in designing their next-generation switch. He describes their design culture as one based on empiric listening paired with a comprehensive rigor and relentless drive to explore endless numbers of component permutations for the best sound. After more than 3 years of development and exhaustively comparing against their competitors, tempus is their answer. This switch is fully designed in-house and has the sole focus on minimizing network noise. Rob admits the biggest reduction of noise was achieved not only with the circuit, components, or its clocks, but especially with tempus' power management and quality of its power supply; the system incorporates a multistage filtered hybrid design to circumvent what Rob felt were sonic compromises in traditional linear and switch-mode power supplies (and even dedicated battery-based power supplies) for audiophile switches. Network Acoustics isolates the power supply in a separate chassis, and the switch is encased in a specially-designed aluminum housing for further shielding. Beyond the power management system, Rob felt that tempus needs to support gigabit speed, have an abundance of ethernet ports to support larger A/V systems, the processing power to effortlessly stream to multiple ports, and a more mature and premium appearance than its predecessor.

I would propose my listening room's network is probably quite polluted since it is also my home office. The Comcast cable signal comes into our living room's Motorola MB7621 modem, and the signal then goes to a Netgear Orbi AX4200 mesh router before connecting with a standard TPLink 8-way switch; from here, one in-wall cable goes approximately 100 feet to my office. There the ethernet cable goes to another TPLink 8-way switch connected to a bunch of noisy work stuff: an Aruba gateway switch, an Avaya PoE VOIP device, and three computers. Then, a QSA-Lanedri Gamma ethernet cable runs from this TPLink to my existing audiophile switch, an Innuos PhoenixNET, from which a Network Acoustics muon pro streaming cable runs to my Lucas Domansky 'Minimax' Music Server. Tempus was evaluated in place of the PhoenixNET as a direct comparison. The remainder of the system consisted of a Lampizator Horizon DAC, a Riviera AIC10-Bal amplifier, and a pair of ZMF Caldera headphones. The system was powered by a Shunyata Denali 6000/V2 conditioner via a mix of QSA-Lanedri, Sablon Audio, and Shunyata AC cords. Standard CAT 5e and CAT 8 contractor-grade LAN cabling was used throughout the house up to the office TPLink switch.

 

[keithc]

(part 2)

During the month-plus tempus burned in, my first impression is that the Roon interface became significantly more responsive; starting/stopping songs or searching new music often had a noticeable lag with the PhoenixNET (compared to my ethernet directly plugged into my streamer), but this resolved with the tempus. This difference in responsiveness is unexpected given the relatively miniscule bandwidth needed by the Roon interface. I am also initially lukewarm about the tempus' appearance; my black version is an understated box, and it looks like... well, a switch, paired with a second PSU box with mismatched appearance (it has a different surface texture and non-rounded corners). While many would agree that network switches are rarely a visual centerpiece of an audio system, I would still say the Innuos gets a slight edge for its not-a-typical-computer-switch aesthetics. Call me shallow, but I'm hoping tempus 2.0 has an option for at least a wood fascia, or perhaps more intriguing visual features. Perhaps British racing green or duotone houndstooth, Rob?

Now to the meat and potatoes: tempus sounds amazing, and the improvement in sound is well beyond any first impressions I have. Even though the Innuos is no slouch, the tempus brings a greater naturalness and realism to my system that leaves me in disbelief. So much for "switches do not have a sound..."

There is a noticeable improvement in the separation and definition of individual instruments. One of my favorite recordings is I Am a Town by Mary Chapin Carpenter (Come On Come On, Qobuz 44.1/16): with tempus the interweaving of the strumming guitar, yearning strings and hard-struck piano are individually-intact yet spatially separated, each with their own beautiful melodies. In comparison, there is a slight blurring together of these elements with the PhoenixNET, such as at 1:20 the piano notes are more hidden behind Mary's voice; this blurring is evident only when the song is played back-to-back across both switches, but obviously enough that it results in my needing to concentrate harder on the song with the PhoenixNET to aurally 'see' the entire performance. In essence this results in tempus sounding 'more relaxed' -- a term which I imagined but never fully understood until now; the music is laid out without microscopic distractions that previously I did not realize were present... as if a certain amount of invisible noise around each instrument or voice has been removed.

Details and tonality also improved. For example, on the opening guitar solo on Dire Strait's Private Investigations (2022 Remaster, Qobuz 192/24) there is a subtle vibrato on each note which was lost with the PhoenixNET. The previously mentioned Mary Chapin's song ends with a contrasting duet with piano treble and deep cello notes, and tempus brings a rightness of the harmonics in each piano strike and the wooliness of the cello such that the song ends in a more romantic and expressive way. In contrast, the same segment on the PhoenixNET shows a slight hint of vocal edginess and incomplete piano and cello timbre, which previously I must have ignored. Adele's explosive vocals on the chorus of Hello (Qobuz 44.1/16) has an openness and magnitude that feels limitless on the tempus, but slightly edgy and strained on the Innuos. Diana Krall's A Case of You (Live in Paris, 24/96) is a very well-recorded solo piece at the Olympia, with her smokey voice, grand piano on the stage, dimmed lights, and very soft crackles of noise artifacts from the analog recording; tempus elevates the distinctiveness of each piano note, softens a bit of her vocal sibilance, and conveys an overall more intimate yet balanced performance. Not to say there is a change in frequency extension, nor a lack of pace, rhythm and drive, but the different elements of the sonic picture fits together in a more cohesive and real manner. The nuances are so difficult to explain, it is akin to DSD compared to Redbook audio.

How does tempus compare against just bare ethernet without a switch? With the naked ethernet, Bon Iver's opening vocals sound muffled on Taylor Swift's Exile, as if it was improperly mic'ed, less ambience and airy; Taylor's voice equally lost the clarity needed to be a quality digital recording, an analogy akin to going from SACD to a 320kb MP3 playback -- the effect is a de-beautification of the instruments and voices in a way that it invokes the term "digital harshness" rather than the smooth delivery of, dare I say, analog playback.

I found the choice of power cords significantly impacted tempus' performance. Comparison of the switches started with a basic Shunyata Venom power cord, however in later testing a newly-released Shunyata Gamma NR cord as well as a custom-made J.A.W. (initials of its maker) proprietary shielded power cords were also used. The Innuos was relatively agnostic to changing power cords, but the J.A.W. cord made a noticeable additional enhancement to tempus' timbre, air, and sense of realism. I'd definitely recommend anyone with a tempus to explore different power cords for an easy additional sonic improvement. Along the same vein, a Synergistic Research Pink fuse was also tried (network switches are wonderful for burning in new fuses!) which conveyed 10% more focus, clarity and details -- in Dire Strait's Sultans of Swing (Qobuz 192/24) the accompanying guitar's at 3:10 hits with a more dynamic twang and ring; songs had a stronger personality. The magnitude of difference after going back to the original fuse was akin to a downgrade in power or ethernet cords. If you have the tempus, stop whatever you are doing and order an aftermarket fuse right away -- as good as it is in stock form, the OEM fuse limits tempus' true performance. The synergistic (pun unintended) improvements using both an upgraded power cord and fuse propels the tempus to a huge advantage over my baseline PhoenixNET.

As a validation experiment, I brought the tempus (with OEM fuse) and PhoenixNET to my friend @kennyb123 's system for a 4-way network switch comparo: he uses an optical fiber to an EtherRegen with a Farad Super 3 and a Mutec master clock. @jeremya , another audiophile, joined us with his Synergistic Research Switch. I was not familiar with the host system's sound, but regardless of our individual tastes in music, all three of us indepedently agreed on our observations that tempus led the pack with its overall superior transparency, tonality and realism. Ironically, the first time we transitioned from tempus to the PhoenixNET, both Jeremy and Ken felt the latter's sound had more density and was more exciting; however on subsequent tracks we observed that the PhoenixNET's presentation was impressive and accentuated the melody ("like we're sitting on Diana Krall's lap"), while the tempus actually sounded more truthful, natural and balanced. Over the hours of back-and-forth switching across the various devices, tempus consistently brought smiles, nods and acknowledgments of "that's the performance" and conveyance of emotions. The scalability of the tempus with better power and ethernet cords was also verified at his house; while the switches each improved with better power cords, the tempus maintained its lead when paired with the best cables, and we found the QSA-Lanedri ethernet cable to outperform the optical fiber input. Ken and Jeremy's independent observations are linked here and here.

In full transparency -- the overall magnitude of change in my system, on the scale of audiophile effects, was small yet clearly evident especially on better recordings. Your mileage may vary, as the impact was larger on Ken's system. My opinion is that a proper network switch is necessary for those who stream digital music but only after they have made solid investments in digital front-end components. And yes, audiophile switches do cost a lot more than off-the-shelf Netgear switches... but there comes a point in one's system when the price of incremental improvement in the DAC or streamer would exceed the cost of the tempus, and the value for performance of the switch becomes evident. And especially when the benefits are repaid across the tens of thousands of streaming hours in an audiophile's journey, this purchase decision for a tempus becomes a no-brainer to me.

I have a newfound enjoyment of my beloved digital front-end. Until now, the PhoenixNET was like the wonderful girlfriend who seemed to have check all the boxes, and one that I could live with forever. But then the tempus came along, and her songs evoke silly laughs, visceral gasps and a joie de vivre that I never knew was missing... and damn, it's hard to go back. Farewell, Innous, we have had some great times, but I can only pick one.

 

[keithc]

Reserved