dCS Vivaldi APEX DAC

Vivaldi is the dCS system in which each function has its own chassis, and the APEX DAC is the part that converts. Inside are the Ring DAC APEX board, the latest dCS Digital Processing Platform and the analog output stage; network streaming and format conversion live in the Vivaldi Upsampler, the system reference in the Vivaldi Master Clock, and disc replay in the Transport II. The Ring DAC is dCS's own discrete converter: an array of 48 equal-value current sources switched by latches at 3 MHz or 6 MHz under a mapping algorithm that chooses a different combination of sources for every sample, so that the small mismatches between components average out as low-level noise rather than correlating with the signal as distortion. dCS has refined the mapper in software for a decade, and the owner chooses between the 6 MHz maps and the original 3 MHz map from the menu.

APEX, introduced in 2022, is the first hardware revision of the Ring DAC since the Vivaldi launched. dCS reconfigured the Ring DAC board, lowered the impedance of the reference supply that feeds the current sources, improved the symmetry of the summing stage and designed a new analog output stage around a compound amplifier, so that the ring is isolated from cable capacitance and load. The company's own figures were more than 12 dB better second-harmonic linearity and a lower noise floor than the previous Vivaldi board. Independent measurement bears this out: John Atkinson in Stereophile measured THD+N of 0.00026 percent at 6 V into 600 Ω with the third harmonic at −127 dB, linearity accurate to about −135 dBFS, a 25 dB drop in noise floor from 16- to 24-bit data indicating at least 20 bits of resolution, channel separation above 125 dB below 3 kHz and a balanced output impedance of 1.3 Ω. Hi-Fi News' lab report found 0.00004 percent distortion at 1 kHz and 0 dBFS, an A-weighted signal-to-noise ratio of 117.1 dB and jitter of 10 ps at 96 kHz.

Because the Vivaldi DAC has no Ethernet port, its inputs are all digital audio interfaces. Two Dual AES pairs (four AES/EBU XLRs) take 24-bit PCM to 384 kS/s and DSD128 from the Upsampler or Transport II; S/PDIF is provided on two RCAs, one BNC and one Toslink; an SDIF-2 interface on two BNCs accepts 96 kS/s PCM or DSD from professional equipment; and an asynchronous USB 2.0 input takes 384 kS/s PCM and DSD128 directly from a computer or server. Three word clock inputs accept references from 32 to 192 kHz; the DAC's own word clock output runs at 44.1 kHz in Master mode or 38.4 kHz in Universal Master Mode, which lets a Vivaldi Upsampler lock to the DAC in a two-box system before a Master Clock is added. Six PCM filters and five DSD filters are selectable; Stereophile found Filter 1 flat to just below half the sample rate with sharp rejection, Filters 2 to 4 trading image rejection for less ringing, and Filter 5 minimum-phase with all its ringing after the impulse.

Jason Victor Serinus reviewed the Vivaldi APEX DAC with the Upsampler and Master Clock for Stereophile and heard a presentation in which "the soundstage was wide, the silence profound, the presentation pristine," with bass and staging more convincing than any dCS product he had reviewed before; the magazine named the Vivaldi APEX its Digital Source Component of 2023. On the Rossini APEX, which shares the DAC core and analog board, his finding was that the Vivaldi's separate chassis, power supplies and isolation give it a clear edge, and that dCS's David Steven put it this way: "Vivaldi seems to have more emotional impact." Jacob Heilbrunn in The Absolute Sound heard bass "weightier and more textured" than the original Vivaldi's and "a more supple and richer musical reproduction," and the magazine gave the DAC a 2024 Golden Ear award.

Balanced and unbalanced outputs are switchable between 0.2, 0.6, 2 and 6 V full scale, and the digital volume control is designed for direct connection to a power amplifier; with a 6 V setting into a high-gain amplifier the lower output levels keep the control in its most linear range. We build Vivaldi systems in stages: the DAC with a server on USB first, then the Upsampler for streaming and Mosaic control, then the Master Clock, with Nordost or AudioQuest clock and AES cables, into Burmester, Boulder or Audio Research amplification and Magico or Sonus faber loudspeakers. The APEX hardware is available to owners of earlier Vivaldi DACs as an upgrade, listed at $9,000 on dCS's current US price list.

Within the dCS range the Vivaldi APEX DAC sits above the Rossini APEX DAC, which puts streaming and conversion in one chassis, and below the Varèse Music System, which takes the separates logic further with mono Differential Ring DACs, a dedicated Core and the ACTUS interface. Choose Rossini for a single-box streaming DAC with most of the Vivaldi's performance; choose Vivaldi when conversion, upsampling and clocking developed and powered separately matter and the system will be built up over time; consider Varèse when the budget allows the final step. We plan Vivaldi most often with the Boulder 2160 or Boulder 2150 monos, the Burmester 218 or Burmester 259, or the Audio Research Reference 330M monoblocks, driving loudspeakers such as the Magico S5, Magico S7 or Magico M7 or the Sonus faber Aida II, Il Cremonese or Lilium.