Media Server Reviews

John Atkinson asked me to review the dCS Network Bridge ($4250), which was designed to be paired not just with the dCS Vivaldi DAC ($35,999) running the current v.2.02 software, but with any DAC. This meant I was forced to endure several months with the state-of-the-art Vivaldi as a replacement for my reference dCS Rossini ($23,999). Oh, how I suffered.

Michael Fremer, in his January 2014 review of dCS's four-piece Vivaldi system ($114,996), of which the Vivaldi DAC is part, called it "the best non–digital-sounding digital system I've heard." John Atkinson, in his measurements for that review, credited the system with "the best digital playback I have experienced."

I determined a review strategy. My main focus would be the Network Bridge, with the sound of the Vivaldi DAC's v.2.02 software upgrade a major corollary. First, I'd listen to the Network Bridge as one of four links in a dCS chain of the Vivaldi DAC running its original v.1.2 software, the Scarlatti clock, and the Paganini SACD/CD transport. Once I'd fully grokked the Vivaldi v.1.20's sound, I'd update to Vivaldi v.2.02 and listen again.

Network Bridge
The dCS Network Bridge is a one-box network player that can serve as a bridge between your source of digital music and your DAC. Inside its housing of machined, aerospace-grade aluminum are hardware and software capable of playing high-resolution music files from a NAS, USB drive or stick, or Ethernet-connected drive. It can also stream content from Tidal, Spotify, and other streaming services.

The Network Bridge's front panel is solid, save for a small blue LED that indicates when the unit is powered up. On the rear panel are two AES/EBU outputs (compatible with dCS DACs); three S/PDIF outputs (one on an RCA); Ethernet, AirPlay, and USB 2.0 (data) inputs; two BNC SDIF inputs; and a third BNC word-clock output. Its built-in antenna is designed for app control and eventual WiFi use; the latter remained inactivated during the review period.

The Network Bridge can play PCM files up to 24-bit/384kHz, all major lossless codecs, plus DSD64 and DSD128 in native or DoP formats. While the Bridge's auto-clocking system is compatible with clock settings within the Vivaldi, Rossini, and other DACs, it can also be used with an external clock fitted with BNC outputs. Multistage power regulation isolates the Bridge's digital and clock circuitry from AC irregularities.

As long as a DAC has at least one AES/EBU or S/PDIF input, dCS claims it will benefit from the Network Bridge. This includes DACs limited to 96 or 192kHz, or that can play DSD only when downsampled to 96 or 192kHz PCM. No matter if a DAC with only one AES or S/PDIF input allows sample rates above 192kHz and DSD64—linearity considerations have led dCS to limit the ability to pass those higher rates to their traditional Dual-AES connection.

Very much a 2017 product—notably, the Network Bridge is Roon-ready—the product's FPGA platform is accessed by a remote, iOS-only phone/pad app. The app permits full control of what dCS claims are the Bridge's bit-perfect wired and wireless streaming capabilities, as well as its input, output, and clock settings. Direct connection to Tidal and Spotify is supported.

The Network Bridge software is easily updated via the Internet using the app's control section. By the time you read this, software to enable serial-data mode for RS-232 control of other dCS products, including the Vivaldi DAC, should be available. Ditto a USB audio output that will allow connection to USB DACs.

While the Network Bridge is equipped with WiFi, WiFi connectivity is limited to 24/96 because dCS feels that wireless transmission compromises performance, and those compromises increase with the sampling rate. dCS recommends hardwiring the Network Bridge via Ethernet.

Given its multiple functions, the Network Bridge is really a local and streaming music file renderer that can locate, process (ie, convert FLAC and other compressed formats to uncompressed WAV), and present to any DAC music files from a variety of sources, local or Web-based. The Bridge also enables the Vivaldi (which has only a USB input) and older, discontinued dCS DACs to play files and stream music in all resolutions and formats the DAC allows.

The Vivaldi DAC has only a single USB and no Ethernet input, which was a deliberate design choice. As dCS Americas' General Manager, John Quick, explained by phone:

"Because the Vivaldi system is our reference statement system, we don't want excessive processing or overactive power supplies to generate noise inside the box. There are advantages to having the network board, with its dedicated power supply and dedicated FPGA processor, running our code in a separate chassis that is pretty inert. This is why the Vivaldi system's upsampling, disc playback, and advanced clocking take place in separate boxes.

"We decided to put a USB input on the Vivaldi DAC for someone who wasn't going to buy the whole system, because that was the least compromised input we could offer that would allow access to file playback. Regardless, prior to the release of the Network Bridge, whose dual-AES connection addresses these issues, we would tell customers that if you have a Vivaldi Upsampler, that's where you want your USB and network plugged in.

"The Bridge is a great option for someone who wants to bring network connectivity to a Vivaldi DAC but doesn't want to spend $22,000 on a Vivaldi Upsampler. Everything the Rossini can do, the Vivaldi DAC can do with the help of the Bridge."

Although MQA processing for dCS products was still in the testing phase during the review period, the first MQA unfolding is expected for the Network Bridge by the time you read this. Ditto for MQA unfolding and rendering for the Rossini DAC and Player. Unless a major ecological catastrophe hits the UK, the Vivaldi DAC's v.2.02 software should be upgraded for MQA rendering by the end of 2017, and the Vivaldi Upsampler will handle MQA's first unfolding. Expect a Follow-Up assessing dCS's implementation of MQA.

The Network Bridge app resembles the Rossini DAC app, with settings that accommodate earlier dCS DACs and DACs from other companies. It also has portals for playlists, UPnP, USB, Spotify, and Tidal.

For much of my listening, I plugged into the Network Bridge one of three USB 3.0 sticks loaded with hi-rez files, or one of two external hard drives, and controlled playback with the Bridge app. Occasionally I connected a Roon-equipped Intel NUC computer to the Bridge via Ethernet, and used the Roon app for playback. Into the NUC were loaded the contents of the three USB sticks and one of the external HDs. This setup let me compare the features and sound of multiple sources and playback platforms.

Vivaldi v.2.02
dCS claims that the Vivaldi system's v.2.02 software upgrade brings multiple audible improvements to the DAC's sound. For one, it enables DSD128 file playback. It also adds a new DSD filter, designated F5, for which, in a press release, dCS claims "better impulse response than [dCS's] previous DSD filters, with virtually no ringing. High frequency noise has also been better suppressed outside the audio band to be more universally amplifier-friendly, and to present the amplifier with a cleaner signal."

In addition to new gain settings and new clocking architecture for the DAC, a new system for mapping the Ring DAC—ie, for determining precisely how the many discrete elements within the DAC core are switched on and off—is claimed to generate lower distortion. According to dCS, it "does an even better job avoiding hardware mismatches that manifest as errors correlated with the music signal, bringing superior linearity, even at low signal levels." You can choose among three Mappers, two of which are new. Hint: New Mapper 3 sounds a mite warmer, softer, more analog-like; new Mapper 1 offers sharper lines and more color contrast.

Putting it all together
I'm so glad that John Quick and his colleague Brad O'Toole delivered in person the Network Bridge, the Vivaldi DAC running software v.1.20, and the v.2.02 upgrade disc—setup required repositioning equipment and running three BNC cables from the Scarlatti clock to the Network Bridge, Vivaldi DAC, and Paganini transport. There were dual AES and analog output cables to hook up, new settings to choose from, and an app to download and master. As I had only one pair of AES cables for the DAC, I switched them between the Bridge and Paganini, as needed.

On the bottom shelf of my four-tiered rack sat most of the power products listed in "Associated Equipment." Both the Nordost QX4 and Isotek EVO3 Sigmas power conditioners were active, because I've found them to be complementary in reducing noise and thus revealing more low-level detail. Ditto for the Synergistic Research Tranquility Bases under the Grand Prix amp stands. To further minimize system noise, I switched on my Roon-enabled NUC only when I used it. Ethernet cables led from NUC to router and from router to Network Bridge.

On the shelves above were the Network Bridge stacked atop the Paganini, the Scarlatti clock sitting on a 1.5"-thick Grand Prix Formula platform, and, on the top shelf, the Vivaldi DAC sitting on another Formula platform. On stands flanking this rack sat a pair of Pass Laboratories XA200.8 monoblocks.

To those tempted to cry foul at my stacking of Bridge atop Paganini transport, or at the absence of any analog source: If this 5' 4.5" Serinus had a single rack tall enough to hold everything, he'd need a stool to reach the top shelf. Nor are two side-by-side multi-shelf racks acceptable—squeezing them and two amp stands between my speakers would make it nearly impossible for me to get to the cables. We do what we must do.

Network Bridge with Vivaldi v.1.20
Minutes after the Network Bridge and Vivaldi DAC v.1.2 were connected via dual-AES, I inserted a USB 3.0 stick in the Bridge. Using the Bridge app, I played a recording of works by J.S. Bach transcribed for the trio of mandolinist Chris Thile, cellist Yo-Yo Ma, and double bassist Edgar Meyer (24/96 WAV, Nonesuch 558933/HDtracks). Although the equipment was not fully warmed up and the cables hadn't settled in, instrumental textures were far more palpable than before.

Thile's fingering was more cleanly articulated than through the Rossini. I could easily differentiate between the leading edges of plucked or bowed strings and the resonant bodies of their instruments. The cello's timbre was so rich and beautiful that I recalled the sound of my friend Elaine Kreston's cello as she sat beside me during a rehearsal. Bass pitches were perfectly articulated—the cleanest I'd heard from these files—and images were palpably larger. Because the instruments felt more real, the music's impact deepened.