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dCS Vivaldi APEX DAC

03-31-2023 | By Wojciech Pacuła | Issue 127

dCS is a British company based in Cambridge focused on development of digital audio sources—D/A converters, SACD and files players. It made its debut in 1987 in the military industry (radar). The first A/D converter, model 950, from 1989 was intended for recording studios, and only after some time they also designed versions for home systems. 

When testing the Rossini player from the British company dCS in 2016, I paid attention to two things, both of which were crucial to understanding my position. The first concerned the Compact Disc format, the second the very act of testing a disc player of this type (and SACD). As I wrote then, many fans of analog records consider 1982, when Philips and Sony presented the CD format, as the end of the "golden era" of sound. In turn, writing about it in 2016, when the machine promoting audio files playback ground everything in its path, could seem anachronistic. Both of these views were wrong. Just stupid.

It's 2023 and again I'm testing a product, which in its basic function is part of a split SACD player, i.e. a device playing physical SACD and CD digital discs (as well as MQA-CD, but more on that in a moment). And they are still, in my opinion, the best way to store and play music. One thing has changed—today we are able to play files in such a good way that you can turn a blind eye to the differences between them and physical media, enjoying the convenience they provide and immediate access to new products.

The tested dCS D/A converter is the latest incarnation of the Vivaldi system, launched in March 2012. APEX, as it was called, "allowed manufacturer to deliver a range of sonic and measured improvements, and enhance the musical performance of two renowned dCS system"; more HERE, accessed: 01/24/2023). This name refers to the new DAC architecture Ring DAC, dCS' most important development:

Following extensive research and development, we've made some major changes to the Ring DAC hardware. We've reconfigured the Ring DAC circuit board and developed an all-new analogue output stage. 

This has allowed us to reduce distortion, improve linearity, and deliver both measured and subjective improvements in a range of key areas, taking the Ring DAC's world-leading performance to a new level. It has also allowed us to further enhance the performance of the much-loved dCS Vivaldi DAC, Rossini DAC, and Rossini Player. (Ibidem)

Earlier, in 2017, the company improved the algorithm that controls the switching of resistors in the discrete D/A converter of its own invention—this version was named 2.0. The upgrade was made by changing the software in one's device. However, APEX was such a far-reaching modification that it was necessary to physically replace the D/A PCB. From the user's point of view the fact that in both cases owners of the Vivaldi and Rossini systems did not have to replace the entire device, but only modernized it, was great news.

On the way to the top

dCS is a manufacturer that has many so-called "first":

  • 1989 dCS 900, the first 24-bit A/D Converter in the world,
  • 1993 dCS 950, the first 24-bit D/A Converter in the world,
  • 1996 one of the first upsamplers,
  • 1998 dCS 954, the first 24/96 D/A Converter in the world,
  • 1998 together with Philips they design the P3D format for DSD signal recording.

All these successes are based on one of the company's earliest developments, i.e. the Ring DAC. The dCS 900 analog-to-digital converter was the first device to feature its 24-bit version (1989). Since then, it has been constantly improved and developed. For example, Ring DAC 2.0 from 2014, the predecessor of the APEX version, offered computing capabilities and work speed twice as fast as previous generations.

The latest Ring DAC uses a digital platform that supports PCM signal up to 24-bit/384kHz, as well as DSD up to DSD128 and DSD in DoP format. dCS converters also decode MQA from all inputs. So it will decode both the MQA signal from the Tidal service, from local files and from MQA-CDs; more about this technique in the article entitled MQA + UHQCD: Hi-Res Compact Disc, or (yet another) death of the Compact Disc (see HERE).

Vivaldi is the top series from dCS. It was introduced to the market in 2012, and two years later we had the opportunity to listen to the complete system at the Krakow Sonic Society meeting (meeting #92, see HERE). The system consisted of four components: SACD transport, D/A converter, upsampler/file player and clock. Later, this series was joined by the Vivaldi One integrated player (more HERE).

Nine years later, it's clear that files are in the spotlight. Vivaldi APEX DAC digital-to-analog converter, used to decode the signal from external file transport became the main element of the system.

A few simple words with James Cook, Head Of Customer Service

Wojciech Pacula How does the timeline for the Ring DAC look like?

James Cook The Ring DAC is a technology that dCS have been working on, in one form or another, since the 1980s. Originally it was called the 'Decorrelating DAC'— later renamed to the Ring DAC—with the underlying technology first being used for radar applications in aviation. Good radar systems need to have a good analogue to digital converter (ADC), and this is essentially a DAC run in a feedback loop.

dCS first reapplied this technology to a DAC in 1993. with the dCS 950, the world's first 24-bit DAC. This featured the first generation of the Ring DAC board. It featured 44 current sources, using 11 4-bit latches per channel, with a ROM device for each channel that ran the Mapper. This generation of the Ring DAC ran until 2007, featuring on the dCS Pro series DACs (such as the 950, 955 etc.), as well as the Elgar and Elgar+ DACs.

The second generation of the Ring DAC came in 2007, featuring on the Scarlatti, Paganini, Puccini and Debussy product ranges. The fundamental approach of this generation remained similar to the first generation Ring DAC, where it used 11 4-bit latches for 44 current sources per channel, with general improvements and refinements made to the DAC and analogue circuitry to increase the performance that could be extracted from it.

The third generation of the Ring DAC was released in 2012, first featuring on the Vivaldi range, then on the Rossini, Bartók, and most recently Lina. The hardware for this generation changed quite drastically. We moved away from using 4-bit latches for the current sources to using single-bit current sources, with 48 single-bit latches used per channel. This had a number of benefits, such as reducing the possibility for crosstalk between bits on individual latches.

The board also featured twin FPGAs on the Ring DAC board to carry out the Mapper functionality, a change from the ROM devices used on previous generations. This meant the Mappers for the DACs could be reprogrammed and changed over time, allowing us to later release the new generation of Mappers with software updates to Vivaldi, Rossini and Bartók.

APEX builds on everything that makes our third generation Ring DAC so special. The fundamental hardware is the same, using the 48 1-bit latches per channel and twin FPGAs to handle the Mapper functionality. Refinements have been made in a number of places across the board, increasing both the measured performance of the DAC and the musical experience it provides. The design of APEX is the work of Chris Hales, Director of Product Development at dCS.

WP What exact is the difference between APEX and Ring DAC?

JC APEX is a hardware redesign of the third generation Ring DAC board design, aiming to increase both the measured and the subjective listening performance of the product. There are a large number of hardware changes across the board with APEX, and these changes live up to the dCS mantra of continual improvement instead of complete redesign, building on the already excellent performance of the third generation Ring DAC.

The changes with APEX include refinements to the reference supply fed to the DAC (reducing the impedance of the reference supply, leading to more stable performance and a reduction in the 2nd harmonic produced by the DAC), improvements to the circuitry distributing the clock signal to the latches in the DAC, replacing individual transistors on the Ring DAC circuit board with a compound pair, and adjusting the layout of components on the Ring DAC circuit board.

The result of all of these changes is that APEX is even quieter than previous generations of the Ring DAC, and over 12dB more linear. Linearity is a crucial aspect of any dCS DAC, meaning what is fed to the DAC's input is exactly what you get at the output—free from any kind of distortion. Ultimately, APEX provides a more resolving, dynamic and exciting performance for the listener. 

dCS Puccini layer with second generation D/A Ring DAC

WP How is it scaled down for Rossini and Bartok series? I mean, how these APEX converters differ from each other?

JC Fundamentally, the design of the APEX boards inside all dCS APEX models is the same. We do not compromise on the hardware or design between the ranges – the improvements which were brought about with the Vivaldi APEX upgrade can be found in the Rossini APEX. The same improvements to the reference supply fed to the Ring DAC, the same improvements to the clocking circuitry, the same analogue output stage improvements resulting in better linearity, can be found on all APEX models.

WP Are digital filters the same in older versions of the RingDAC and the new APEX?

JC Yes, the digital filters found inside the APEX variants of dCS DACs are identical to those found in non-APEX versions.

For the Vivaldi, Rossini and Bartók ranges, the last update which changed the digital filters available inside the products was the 2.0 software update for each product. This added a new DSD filter, Filter 5, to the products. This filter has a relaxed roll-off with a smoother phase response.

WP What's next? I mean, what are you plans for the future?

JC dCS have always striven to push the boundaries of digital audio performance. Whether this comes in the form of no-cost performance enhancing software updates to our products, in the form of hardware upgrades to existing products, or new product lines. APEX is another significant step on this journey, bringing leaps in performance to any audio one may listen to—irrespective of source or audio format.

Our Research & Development teams are always hard at work redefining what is possible from digital audio. Whether these developments take the form of software, hardware or new products altogether remains to be seen, but whatever happens, exciting things are on the horizon for dCS fans.

Vivaldi APEX DAC

Vivaldi APEX DAC is A D/A Converter. It offers as many as ten digital inputs and sockets for communication with an external clock or for sending the clock signal to a transport. There are also two pairs of analog outputs with adjustable maximum voltage. The digital signal can be digitally filtered in a software filter of our choice - there are four for PCM signals, and two for DSD. The device also offers adjustable (in digital domain) output voltage, hence it can directly drive a power amplifier.

Digital inputs support PCM and DSD signals: USB 2.0 (24/44.1 - 384 kHz PCM, DSD64 & DSD128 in DoP), 4 x AES/EBU and 2 x S/PDIF, 1 x BNC S/PDIF (all 24/ 32-192 kHz PCM & DSD64 in DoP), 1 x S/PDIF TOSLINK (24/32-96 kHz PCM), 1 x SDIF-2 on two BNC sockets (24/32-96 kHz PCM or SDIF-2 DSD) . There are RCA and XLR analog outputs—the device is a fully balanced design. The user can set the maximum output voltage in four steps: 0.2V, 0.6V, 2V and 6V.

All information is shown on a medium-size display. The letters are rather small and only when turning the volume knob do large numbers appear. The display also helps to use device's menu using the buttons located next to it. The chassis is made of aluminum cutters and plates, which helps to control vibrations and reduces RFI and EMI. To enhance the vibration damping effect, the interior is lined with damping panels. On the front panel we have a characteristic "wave" shape. Even though the design of the Vivaldi series is eleven years old, it is still very impressive. The company explained this aesthetic as following:

The curves on its fascia represent movement, rhythm, life and natural forms—a nod to our emotional connection with music and the sound that inspires us to create - while its understated top and side panels, streamlined controls and ordered rear panel help to aid performance and ease of use. (Ibidem)

The circuits inside were assembled in SMD technology. The converter PCB and its power supply in the APEX version are now of a higher class than before. It uses Xilinx Spartan DSP chips with more processing power and higher specification components than before, including Wima polypropylene capacitors and better resistors. Two shielded and mechanically isolated transformers are placed on the side. They allowed manufacturer to separate the analog and digital sections. dCS reports that active power supplies now operate at a lower temperature and that the whole is more resilient to fluctuations in the AC supply voltage.



The Vivaldi APEX DAC digital-to-analog converter was tested in the "High Fidelity" reference system. It was compared to the D/A section of the Ayon Audio CD-35 HF Edition SACD player, and the comments regarding its sound also referred to other top players I tested: Gryphon APEX, Accuphase DP-1000/DC-1000 and Esoteric K-01XD.

The dCS converter was placed on the top shelf of the Finite Elemente Pagode Edition Mk II rack and was powered by the Siltech Triple Crown cable. The signal was sent to it from three sources: SACD transport, CD transport and a laptop. The first one was the Vivaldi APEX Transport, connected to the DAC with a Dual AES connection. I used it to listen to SACD discs, with the DSD signal sent to the DAC. I also used it to transmit the signal from MQA-CDs with a resolution of 24-bits and 354.8kHz. I connected the transport section of the Ayon player to the RCA input, which allowed me to play CDs, and the laptop with the JPLAY Femto software to the USB port.

In the converter's menu, I selected digital filters - for the PCM signal it was filter no. 2, and for DSD no. 4. The basic test was performed with an external preamplifier Ayon Audio Spheris III. For dCS I selected 2V output, and the volume level was set to "0.0 dB". Separately, I also listened to Vivaldi connected directly to the Soulution 710 power amplifier using the volume control in the DAC. It was an excellent sound. And yet I preferred the sound of the dCS with an external preamplifier. These were comparable performances, but different enough to speak of taste and adaptation to a specific system.

Recordings used for the test | a selection

  • Elgar Cello Concerto/Sea Pictures, wyk. Jacqueline du Pré, Janet Baker, London Symphony Orchestra, cond. Sir John Barbirolli, EMI/Esoteric ESSW-90254, "MasterSound Works, SACD/CD (1965/2022); more HERE |PL|.
  • Nat King Cole, Love Songs, Master Tape Sound Lab | ABC Recor AAD-245A, "Almost Analogue Digital” series, Master CD-R (2015); more HERE.
  • Dead Can Dance Anastasis, [PIAS] Entertainment Group, PIASR311CDX, CD + USB WAV 24/44,1 (2012) review HERE |PL|.
  • Cannonball Adderley, Autumn Leaves w: Various, Jazz Hi-Res CD Sampler, Universal UCCU-40126/7, CD + MQA-CD (2018).
  • George Michael, Older, Epic | Aegean/Sony Music Labels SICP-31544-5, 2 x Blu-Spec CD2 (1996/2022) review HERE |PL|.
  • Thomas Kessler, Close to Silence, Hypersensitive Recs. LC 91631, Master CD-R (2022); review HERE.

Ayon Audio + dCS

I cannot describe it in any other way than "silky"—this is the impact of the sound in the tested converter. The piano from the Master CD-R by Thomas Kessler Close to Silence had an incredible charm. It sounded as if the pianist had used yet another computer plug-in during sound processing, the name of which could be just like: silk.

The British device has something in the sound that evokes the sound of SACDs. This is, perhaps above all, fluidity. The silkiness of the attack I was talking about is part of it. Hence the formation of the sound on the Kessler disc had an organic coherence. These were not separate details, but a working, almost "breathable" whole.

And at the same time we are talking about an incredibly spatial sound. The panorama extends across and to the back of the stage as in a panoramic image. Interestingly, the device does not focus in any exaggerated way on sound sources. They are clearly accentuated and have clear contours. And yet, in comparison with the Ayon, but also with the two-box Accuphase DP-1000/DC-1000 player, if I remember it correctly, the dCS seemed to slightly "let go" of pushing the sound, focusing on the midrange, on sustain.

George Michael from the remaster of Older, released in Japan on Blu-spec CD2 (BSCD2), seemed to have a proper 'feeling,' it was shown in a large space, and presented far back in the mix with his additional vocals, but also backing vocals in Fastlove were perfectly legible. It's rare. This shows that the Vivaldi APEX DAC is extremely resolving. It uses it to show all the layers, details, to create a real spectacle.

The aforementioned Ayon and Accuphase players emphasize the saturation of the attack more strongly. dCS shows it, as I say, smoothly. Still, it seems to deliver a brighter, clearer sound. Probably because the center of gravity is set a bit higher in it, but also because it is simply more resolving. Perhaps that is why its presentation is so incredibly impressive, both in the first hour of listening and after a few days.

The device perfectly handles the large scale of a symphony orchestra, as I heard from Jacqueline du Pré's Elgar's Cello Concerto/Sea Pictures , and excels at studio jazz recordings with a string section like Nat King Cole from the 1950s and 1960s, and finally, the massive spaces of Dead Can Dance's Anastasis. Even recordings with the "stereophony" that may be impressive but it certainly is not real, benefited from it. This was the case, for example, with the Autumn Leaves track from Adderley Cannonball's Somethin' Else. This is a classic recording for the 1950s, i.e. with discreet instruments recorded very closely, arranged by Rudy Van Gelder, the sound engineer, along the channels—the drums are in the left, and the other instruments in the right one.

However, something special happens with devices of this class, like the dCS. Although the sound sources are monophonic, they are not entirely monophonic. Van Gelder recorded the band together, in one room, on two tracks at once (and in parallel, on a mono tape recorder). Along with the direct sound, the acoustics of the room were also recorded, including the faint sounds of other instruments. When it's reproduced well, the effect is amazing, like we're listening to a real band in a real space.

dCS did something else that happens only with top devices, be it analog or digital: it also showed, right in front of me, the reverberation coming from the so-called "reverberation plate" EMT 140. And it showed it in a way that was clear and distinct. Most often this element is extinguished, because the level of sound coming from the left and right side is high enough to mask everything that is in the middle.

The Vivaldi APEX is therefore transparent, clear, distinct, resolving, but also silky. It also has beautifully saturated colors. Maybe not as much as in the tube Ayon, in the Gryphon CD player or in the Esoteric SACD player, but you can't have everything. In turn, everything I mentioned above, and let's add to that the incredibly large and accurate stereoscopic sound panorama, was not presented at this level by any other source I heard in my life.

What's more, everything I mentioned can be magnified by about 0.5 when we supply the converter with a hi-res signal. You will find more about the connection with the Vivaldi APEX Transport, which plays SACDs and sends a DSD signal to the converter, below. Now let me say a few words about PCM signal and MQA files decoding. I played a lot of material from my new laptop using the USB input, but I got a more precise description of the sound by listening to MQA-CD samplers, released on UHQCD discs; dCS is one of the few disc players that can do this.

The material decoded by the converter to the form of 24-bits, 352.8kHz sounded simply wonderful. It was soft, it was saturated, it was even more spacious. With a high-resolution signal, dCS brilliantly focuses on the signal sources, but without taking them out of context, i.e. the acoustics. With CDs and 16/44.1 files it was all great, I had no doubt that I was listening to a top system. And yet with the hi-res signal I got something "extra", i.e. the sound that got 'loose,' relaxed, that breathed. Again, it was all there before. But the moment with files and high-resolution signal allowed Vivaldi to show what it is really capable of.

Vivaldi Transport + DAC

The basic thing: the complete dCS system fantastically defines the sonic attack. In this respect, it is one of the best devices I've heard, perhaps the best. Only the Weiss DAC502 D/A converter with CD transport could do something similar. And it, if I remember correctly, was not so fantastically differentiating.

Because the Vivaldi APEX system delivers, on the one hand, full sound, close-up sound, and on the other hand, this sound is extremely carrying and spatial. By saying "carrying" I want to emphasize its detachment from the physical presence of loudspeakers and electronics, and "spatial" that the panorama shown is large in all dimensions. So much so that track no. 14 from the Ultimate Audiophile Reference Test Disc, used to assess the correct presentation of the stage height, was reproduced much better than on my Ayon.

That's why I heard the layers on the Nat King Cole's Love Songs in such a perfect way. Recorded together, i.e. with a vocalist in the same room as the orchestra and the accompanying band, it has never been so spacious before. What's more, I don't think I've ever heard individual layers in such a good setting and arrangement. There was the foreground with Cole's voice (recorded with a Neumann U47 tube microphone), the background with strings, and the other instruments on the sides.

What Ayon does differently, what I have heard before with Gryphon and Esoteric, and what I have already paid attention to before, is the saturation of colors. The dCS system is perfect in this respect. The Ayon enhances the foreground more strongly, it goes deeper into the three-dimensional body of the sound source. The difference is not big, for many listeners it may even be negligible. However, we are talking about high-end, and here each shift of emphasis is tantamount to a significant change.


For years dCS has been defining what can and cannot be done in the world of digital sound sources. In both recording studios and home systems, their products are usually key components. There are sources that are just as good in individual aspects, and in some even slightly better, but none of them do as many things so well.

The Vivaldi APEX DAC offers a perfectly smooth, fluid and coherent sound. Its spaciousness, or rather the stereoscopic illusion of space, is of absolutely top quality. In timbre, it draws attention to the emphasis on the midrange. Not warmed up, mind you, but illuminated, which differs this source from most turntables. The bass is perfectly readable and well controlled. Its lowest range is smoother and a hair less energetic than with the other mentioned sources. However, this is part of the "package," in which we get the whole range properly balanced and well thought out, in which nothing is emphasized or masked.

Simply put, it is a top digital source, one of the best in the world, which is why we honor it with the GOLD FINGERPRINT.

Technical specifications (according to the manufacturer)

  • Output signal level: 2 or 6 V rms
  • Output impedance: 3 Ω
  • Minimum output loading: 600 Ω (recommended 10 kΩ-100 kΩ)
  • Digital inputs: USB 2.0, 4 x AES/EBU, 3 x S/PDIF (2 x RCA, 1 x BNC) 1 x S/PDIF Toslink,1 x SDIF-2 (2 x BNC), 3 x Word Clock inputs
  • Noise: <-113 dB0 (20 Hz-20 kHz, unweighted, 6 V)
  • Power consumption: 23 W typical, 30 W maximum.
  • Dimensions: 444 x 435 x 151 mm (W x H x D)
  • Color: silver or black



Price (in Poland): 217 000 PLN

Contact: Unit 1 | Buckingway Business Park

Swavesey | Cambridgeshire



Provided for test by: AUDIOFAST http://audiofast.pl

text Wojciech Pacula

translation Marek Dyba

photo High Fidelity | dCS

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