dCS – The Varèse Core is one of the most complex audio components we’ve ever made, in both its physical design and technical abilities. It is an integral part of the Varèse Music System, working in tandem with the Varèse Mono DACs, User Interface, Master Clock and Remote Control to stream and play music from various sources.
When developing Varèse, we set out to reinterpret state-of-the-art, bringing listeners unparalleled resolution combined with an intuitive user experience. We wanted to build on our previous breakthroughs to deliver sound with even greater fidelity, whilst at the same helping listeners get to their music faster and control their system with ease.
The Core was developed to help us achieve this. Acting as the heart or central hub for the Varèse Music System, it connects with each component and distributes the relevant control and timing signals to each unit, whilst also monitoring operations to ensure all components are operating in sync.
It also handles most of the Digital Signal Processing (DSP) within Varèse and works in tandem with the User Interface and Mosaic ACTUS app to enable various control and display features.
A processing powerhouse, it manages a multitude of complex operations and enables the simplest setup and use of a multi-component dCS system to date, a feat made possible with new dCS technologies and the Core’s unique physical construction.
Here, we take a closer look at the Core’s design, exploring its role within the Varèse system, the benefits it brings to owners, and the features that drive its performance…
Advancing performance: supporting the Varèse Mono DACs
Improving performance is our driving goal when developing products. Our engineering team are always exploring how we can deliver sound with even greater fidelity and in turn, bring listeners an even deeper connection with their music. This drives us to constantly explore how we can improve existing platforms and technologies, and build on our previous breakthroughs in digital playback.
Sometimes, this work results in new features or performance upgrades for existing products. Sometimes, it leads to the development of whole new systems and patented technologies.
As we’ve discussed in previous articles, Varèse started with a project to explore how we could improve DAC performance and push the capabilities of our Ring DAC platform (the bespoke D-A conversion system found inside all dCS DACs).
This led us to create a new DAC architecture, a patented clocking protocol, and the first ever dCS Mono DACs, which in turn led to the creation of a whole new system.
The Core was developed to support this new architecture and ensure the Varèse Mono DACs operate to the best of their abilities.
From our experience creating professional recording equipment, and multi-component playback systems, we knew we could increase performance by reducing the processing demands placed on the Varèse Mono DACs. With this in mind, we set out to create a product that could manage a range of processing tasks from noise-shaping and filtering to oversampling – processes that are essential to ensuring good sound quality when audio signals are converted from digital to analogue.
In previous dCS systems such as Vivaldi APEX, some DSP was carried out within a dedicated Upsampler. The Varèse Core takes this approach further, managing almost all essential processing. The only DSP functions handled within the Varèse Mono DACs are the final modulator stage of audio conversion, where incoming audio is converted to the 5-bit ~6MHz format used by the Ring DAC, and the Mapper, where signals are distributed to the Ring DAC’s current sources. Everything else – oversampling, filtering of PCM and DSD signals, and format conversions such as converting PCM data to DSD where required – is carried out in the Core.
Offloading processing requirements to the Core means there are fewer micro-drains placed on the power supplies within the Varèse Mono DACs. This means the supplies feeding the Ring DAC’s circuitry and output stage are cleaner. This, in turn, leads to better performance and improved sound quality, with fewer non-linearities (unwanted effects such as noise and distortion) in the audio.
With the Core handling almost all DSP, the Varèse Mono DACs are able to focus purely on digital-to-analogue conversion, and the specific processing functions that rely on the Ring DAC’s hardware. This, in turn, helps to ensure that the Mono DACs are able to operate to the best of their abilities, without performance being in any way compromised or limited due to additional processing demands.
A new user experience: simplifying system setup and control
Beyond performance, user experience is another primary concern for the dCS team. We continually review and monitor the design of our products and apps to identify how we can further streamline and enhance people’s listening experience – always with the goal of removing friction or distractions.
With Varèse, we wanted to radically simplify system setup and use, making it easier to install and connect components. We also wanted to streamline how products interact and deliver an even richer playback experience with enhanced displays, browsing and control features.
This was made possible through the development of ACTUS, a bespoke interface developed by dCS engineers.
ACTUS enables the Core to connect with each Varèse component and send the relevant audio, control and timing signals to each unit via a single cable running between the unit and the Core. With the exception of the Varèse Clock, which must be inserted into a dedicated input, Varèse components can be connected to any one of the ACTUS inputs on the Core, and the Core will automatically detect which unit is connected to which port.
This configuration has enabled us to radically simplify setup, reducing the steps and time required to connect and configure components for optimal playback. The Varèse system features a single set of user settings for key processes such as filters, for example, instead of individual settings for each component. This means listeners no longer have to navigate various options and adjust settings on multiple products before listening.
We have also streamlined clock settings, removing the need for listeners to manually adjust settings via Sync Mode before playback. If a Varèse Clock is connected to the system, the Core distributes the Clock’s reference signal to all units via ACTUS. If there is no Clock connected, the Core acts as the master clock, generating a clock signal using our patented Tomix protocol to keep all units operating perfectly in sync. All this is done automatically thanks to ACTUS, with no input required from the listener.
In addition to managing most of the system’s DSP, and simplifying setup, the Core enables listeners to easily control Varèse settings and view key information at a glance through the dCS Mosaic ACTUS app and Varèse User Interface. Listeners can view detailed track information and full-colour album artwork on the User Interface’s full-colour touch screen. They can also view settings and information for all Varèse units connected to the system via the Mosaic ACTUS app, making it easier to access information such as current firmware versions. These features and UX improvements are made possible with the development of ACTUS and the Core.
Designing for the future: modules and optional expansion
Alongside performance and user experience, longevity is another major focus for the design team at dCS. We believe our products should deliver a state-of-the-art experience throughout their lifespan. This means building flexible, upgradable hardware that can be updated over time to bring listeners new features and benefits. It also means thinking about the potential ways in which a listener’s requirements or desires might evolve during their time with a product, and building in various features to support this.
With Varèse, we were keen to ensure we could support whatever new platforms or developments might arise in the next generation of music playback. We knew we needed to include plenty of processing power, as well as the option to insert or add new hardware.
The Core has the largest amount of processing power of any dCS product to date, with two i.MX 8 System on Modules (SoM) as well as an Artix 7 FPGA. The Artix 7 handles the main functions of the Core. The two i.MX 8 SoMs carry out different functions: one runs the ACTUS interface, allowing ACTUS signals to be encoded and decoded, with the relevant information, audio and clocking signals then sent to the FPGA for processing. The other forms one half of the streamer inside Varèse. It is paired with a StreamUnlimited Stream1955 in the Varèse User Interface, and the two operate in tandem, communicating via ACTUS to support streaming via Ethernet from various services. This enhanced processing power provides ample scope to support any future streaming developments that might occur.
The Core also features three expansion bays, which provide the ability to add new functions or connectivity options over time via optional hardware modules. Our first such module allows dCS Rossini and Vivaldi Transports, as well as other AES and USB sources, to be connected to the Varèse system.
As with all dCS products, Varèse components feature flexible firmware. This allows us to upgrade performance and add new product features via software updates, delivered free of charge through the Mosaic ACTUS app.
With Varèse, we’ve streamlined the upgrade process to ensure all units connected to the system are upgraded at once whenever an update is carried out, removing the need to update firmware on each component in turn. All this helps us to ensure that the system can continue to evolve, reflecting our longstanding commitment to continual product development.
Stretching the Limits of Construction
Developing the Core was a huge undertaking, with our electrical, software and industrial design teams all working in tandem to create the chassis, circuits and supporting technologies. From a physical standpoint, it is perhaps the most advanced and complex dCS product to date, and one that required extensive prototyping and testing, combined with the use of cutting edge technologies never before seen in high-end audio engineering .
Each Core unit utilises a flex-rigid circuit board, which folds to fit the central chassis. Utilising a folding PCB design allows us to protect the product’s FPGA and sensitive clock circuitry from electromagnetic interference, as we are able to isolate them from the power supply modules by placing the components on different sections of board, which are joined to the other sections with flex-rigid connectors and mounted on different axes of the chassis. This approach allows us to effectively utilise the space within the chassis. It also provides scope to add expansion modules without using flying leads or ribbon connectors which could affect performance.
We first employed flex-rigid PCBs in the dCS Lina series (a range that benefits from breakthroughs made during Varèse R&D). The Core’s flex-rigid PCB is even more complex than the Lina DAC’s, due to the shape and nature of the product. The Lina DAC features four points of flex, meaning it folds along four axes. The Core PCB has nine, with a huge number of delicate components mounted to its surface, and its construction has pushed us to test the limits of PCB manufacture.
The Core chassis, meanwhile, is milled from billet aluminium, which is machined with five-axis CNC machines. The flex-rigid PCB folds to fit the central chassis structure, allowing us to make effective use of space within the unit, whilst leaving room for additional hardware modules. The external casework is also milled from billet aluminium, which is then anodised.
Supporting a new vision for playback
The Core is the first product of its kind from dCS, and its design, construction and range of features supports our vision for the future of playback: to deliver complete musical immersion, and the highest levels of fidelity, combined with richer visual displays, more tactile control touchpoints, and a simpler, more intuitive UI. It is an essential part of the system, working in tandem with all other components to deliver our most revealing musical experience yet…