Atlantis Reference Server

Description

When WADAX designed and built the Atlantis Reference DAC, the objective was clear: to redefine the musical possibilities of digital media. That goal was not only met—it was surpassed. Through a fusion of rigorous engineering and breakthrough technologies, the Atlantis Reference DAC has earned universal acclaim from the world’s most exacting reviewers. It hasn’t just outperformed competing products—it has done so by a considerable margin, setting a new benchmark for digital playback and becoming the definitive reference against which all others are measured.
Now, WADAX has applied the same uncompromising design philosophy to server technology. Every aspect of conventional wisdom—from operational protocols to circuit topology—has been questioned. Every engineering detail—from chassis construction to the modular, future-proof card-cage architecture—has been scrutinized and reimagined. Where traditional solutions have limited performance, WADAX has redesigned or reinvented.

The result is the Atlantis Reference Server: a server unlike any other. It incorporates proprietary technologies to deliver musical performance that conventional servers cannot approach. But WADAX’s ambition extended beyond sonic excellence. The goal was to combine unmatched musical fidelity with the expansive reach and accessibility of streamed music and high-resolution file playback.

Once again, “Reference” means Reference. And once again, WADAX has succeeded.

Isolate, Isolate, Isolate…

Digital signals are vulnerable: They can be impacted by microphonic interference and RFI/EMI induced noise, degraded by poorly executed transfer standards and badly engineered connectors. Preserving their integrity means first protecting them from external influences…

Isolation from spurious noise and power supply artefacts

Research into the fundamental engineering parameters limiting the performance of existing streamers quickly established power supply quality and related noise as critical factors in undermining the quality and integrity of stored and streamed music files. Predominantly based on computer hardware, many servers rely on stock power supplies and regulation, even if they are fed from an audio grade transformer.

The Reference Server is driven by a heavily regulated, multi-stage power supply derived directly from the supplies developed for the Reference DAC. It is so sophisticated and so quiet that the noise-floor of the DC reaching the unit’s active devices is almost impossible to measure. It’s so quiet, that during development we needed to rely on virtual modelling and to develop entirely new measurement protocols to assess advances in performance.

• 3 large proprietary power transformers
• 5 stages of power supply regulation
• Over 200 discrete parts
• Optimized for rejection of external conducted and radiated emissions while also extracting and eliminating the naturally generated electromagnetic noise inside the chassis.
• Mechanically decoupled from critical circuitry to avoid any possible cross-contamination into the critical digital circuitry.
• Based on the proven Reference DAC power supply topology

But there’s no such thing as too much power supply, so the Reference Server is supplied ready to accept the upcoming, external Reference PSU, a full-chassis upgrade that results in almost complete freedom from AC noise, ground noise, RFI and EMI induced interference, establishing the foundation for unprecedented performance from streamed music and file replay.

Isolation from mechanical and electrical breakthrough

The Reference Server’s precision machined chassis is a complex and ultra-rigid construction that doesn’t just isolate vulnerable data from the outside world, it isolates the individual sections within the server itself, mechanically and electrically grounding each critical section, preventing the transfer of mechanical or radiated energy from one to another. Safe from external noise sources, the massive outer housings and precise card slots for each separate circuit block ensure that your fragile digital data is safe from self noise generated within the replay chain too.

• Machined from 150 kg of high-spec aluminium alloy.
• The chassis assembly is constructed from more than 50 individual, precision-machined parts.
• Parts are classified and assembled according to their mechanical and vibratory behaviour, to create a sophisticated mechanical cascade, designed specifically to transport and dissipate structural energy.

Isolation from the network

At first, this might seem counter-intuitive. After all, high-res files stored on your server and files streamed by it all pass across your domestic network. That’s unavoidable. But the network – even the most carefully constructed network, using audiophile switches and cables – is still an incredibly noisy environment, based largely on computer industry hardware and protocols that have almost no audiophile sensibilities. Storing and rendering a file with extreme care is pointless if you then use a noisy network to transfer it to your DAC!

Rather than relying on the Ethernet to carry your fragile data from the Reference Server to your DAC, Wadax prefer a direct link using USB. But no ordinary USB. Rather than off-the-shelf components, they build their own USB physical layer driver to ensure accurate data transfer. WADAX provide a mechanical support for the cable, to deal with the issue of incompatibility between the USB connector and heavy, audiophile grade USB cables, so that the weight of the cable cannot compromise the performance of the connection. But most important of all, they provide a unique solution to the issues inherent in data encoding, transfer and cable connections – Digital Waveform Control.

The Challenge

For years, the computer industry has been built around the total acceptance of bit-perfect copying, essential for the accurate downloading of software and the transfer of data. But from an audiophile perspective, there are a number of issues with current bit-perfect protocols. In theory, a buffered input at the receiver (DAC) end of the transfer prevents cable-induced distortion, but this overlooks two important factors. In any buffered system, the system itself has a transfer function that is constant and thus effectively invisible. More importantly, digital transfer actually occurs in the analogue domain. The USB encoder must convert the digital data to voltage square-waves in order to transmit it down the cable, reconverting to the digital domain at the far end. The problem is that producing perfect voltage square-waves is far from simple, even with a purpose-built, high-end USB encoder.

Once again-in theory-this shouldn’t matter, as the buffered input clocks and reconstitutes the data. The problem is that this process effectively ‘counts’ data blocks rather than assessing their shape, so distortion and displacement in the waveform, induced in the analogue domain, remain incorporated in the reconverted digital signal, invisible to the digital encoder. That doesn’t matter in many real-world computing cases, where the raw data is essentially simple binary. But in the case of audio recordings, that data is incredibly time-, amplitude-, and phase-sensitive, with small errors rapidly eroding the integrity of the whole.

Once WADAX researched the problem and realised its implications, a whole series of related issues fell into focus. In particular, it explained why different USB cables sound so different—and why different lengths of the same cable also sound different.

Digital Waveform Control

The Wadax digital components employ the company’s proprietary MusIC Chip 2 technology, a feed-forward error correction system that compensates for time, amplitude, and phase errors in the D-to-A conversion path. Using the same technique, adding the inverse of the transfer function error to the signal—Wadax engineers realised it was possible to compensate for bit waveform distortion in the USB interlink. However, unlike their DACs, which operate within a closed system of known elements, the universal nature of the USB interface required a user-adjustable corrective solution.

Their answer is the Digital Waveform Control: a set of three rotary knobs that allow users to adjust and compensate for errors in the rise-time and amplitude of the transmitted signal, as well as the spacing on the return channel, effectively counteracting echoes and reflections. Users can establish three preset compensations to match the replay characteristics of different streaming services or locally stored files.

The results are as immediately audible as they are musically significant, finally elevating high-resolution file replay to the level of musical performance it has long promised—but so rarely delivered.

• DWC optimizes the sound of the USB interface: The only user-adaptive USB physical layer interface used in the audio industry.
• Extreme complexity: Constructed from more than 200 parts mounted on 12 proprietary circuit boards.
• Extreme attention paid to electrical and mechanical isolation and decoupling.

AKASA – because the best transfer system deserves the best interface

Having developed the DWC feed-forward correction system, WADAX set out to further advance interface technology by creating a proprietary optical connection designed to optimise the transfer of complex and fragile musical files. Collaborating with a leading Japanese optical-engineering firm for the fibre-optics and Neutrik for the connectors, WADAX designed and built the AKASA optical interface.

This proprietary solution requires the installation of dedicated driver and receiver boards in both the Atlantis Reference Server and Reference DAC. AKASA pushes performance beyond expectations, eclipsing all existing digital standards and challenging the musical capabilities of every known audio source. With AKASA, file replay finally comes of age.

And not forgetting the Roon Browser

Sorting and handling files, while maintaining compatibility across platforms and software updates, presents a significant software-based challenge. Rather than allocating extensive resources to developing a proprietary file browser, WADAX chose to focus its efforts on engineering and operational innovation. To that end, the company has integrated the Roon browser into the Atlantis Reference Server, widely regarded as the most intuitive and comprehensive interface available.

This integration not only makes the Reference Server exceptionally user-friendly, but also ensures seamless compatibility with existing Roon-based storage systems and libraries. As the most widely adopted platform for music file management, Roon provides users with the simplest upgrade and transfer path, allowing effortless access to content stored on Nucleus servers and NAS drives.