With the increasingly widespread streaming of digital music content to our audio systems, either from discs or streaming services (e.g., Tidal or Qobuz), many audiophiles are finding the need for an audio-grade Ethernet switch to connect their home computer network modems, routers, computers, drive arrays, etc. to an increasingly wide array of devices to mediate the transfer of digital content to digital-to-analog converters. As my digital streaming “front-end” has been in development for the last year and half or so, I’m finding there are now better audiophile-grade solutions that provide network access to my nearly 4TB of disc-based digital content, and to new content via streaming services.
UpTone Audio is a small audio-products firm based in Northern California. Company principal and founder, Alex Crespi, has been in the audio business for over 30 years, and was one of the co-founders of the well-regarded audio products company, Hovland, which was started in 1999 and closed in 2009. UpTone was founded in 2010, and all of its products are developed in close partnership with professional electronics engineer, John Swenson, who has had a long career designing the power-distribution networks deep inside large custom computer chips (the sort of devices that run high-speed network data centers). As UpTone Audio, Crespi and Swenson have developed a successful range of products for digital playback including the REGEN line of digital audio products and the UltraCap line of linear power supplies for digital components and music servers. John is also well-known as the hardware engineer for the popular Sonore Rendu series of products.
I purchased my $640 UpTone Audio EtherREGEN in October, 2019, and I can unequivocally say it has been instrumental in getting the audio performance of my digital streaming front end to a level where it is now as fully engaging, immersive, and enjoyable a musical experience as my turntable-based analog system.
Description and Features
The UpTone Audio EtherREGEN Ethernet switch utilizes the same oval-shaped aluminum case used for many UpTone Audio products, and measures 112mm x 110mm x 30mm. Of note, UpTone has specifically designed EtherREGEN so that it does not require an external linear power supply to provide nominal performance. Rather, it comes with an UpTone Audio switch-mode power supply specially designed to prevent the passage of high source-impedance leakage current to the EtherREGEN (more on this later).
The EtherREGEN is unique among Ethernet switches in that it uses a circuit topology called the Active Differential Isolation Moat or ADIM that completely isolates the side of the switch used for connecting network devices (typically the “A” side) from the side connected to the renderer, network bridge, or streamer (typically the “B” side). The ADIM provides electrical, galvanic, and noise isolation between the two sides. I’ll discuss the rationale and function of the “moat” in more detail in its own section in this review.
On the “A” side of EtherREGEN is a SFP (small form-factor, pluggable) cage for making fiber optic connections using an optical transceiver (Figure 1) and an RJ45 module composed of four specially manufactured copper Ethernet ports with status lights. There are 12 transformer cores in each port and the center-taps of these cores are grounded using capacitors to block port-to-port leakage current.
The “B” side of EtherREGEN (Figure 2) has a DC-power barrel jack, ground post, a single 100-Megabit RJ45 port with status lights, a switch for selecting the internal or an external clock, and a BNC connector for connecting an external clock, if hot-rodding your EtherREGEN is desired. The standard impedance for the clock connector is 75-ohm, but a 50-ohm clock connection can be ordered from UpTone Audio at no additional charge. While EtherREGEN works identically in both directions, the “B” side is typically connected to the computer, streamer, network bridge, endpoint renderer, etc., with a copper Ethernet cable. DACs that have an Ethernet input can be directly connected to the “B” port.
By Stephen Scharf
I’ve worked as a molecular biologist for my entire professional career. As one of the inventors of Polymerase Chain Reaction (PCR), I worked in human molecular genetics and developing molecular-diagnostic and DNA forensic testsMore articles from this editor
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