The ZERO – UNO
The natural sound and the rhythm of the music have been the key objectives during the design process of the ZeroUno DAC.
This is achieved by:
- audiophile grade components
- discrete tube output stage with low noise and audio grade power supply
- DAC interstage coupled by special wounded Lundahl amorphous core transformers
- SABRE ES9018S DAC chip with proprietary audiophile firmware
- independently (quasi battery) powered USB input to eliminate electrical noise potentially
- induced by the USB cable from the connected computer
- four layer mother board for minimum internal wiring avoiding ground loops and electromagnetic induction
- dedicated power supply architecture
- comprehensive noise reduction for all digital circuits
- ultraprecise clocks
- The circuit of the ZeroUno DAC is based on the ESS SABRE32 ES9018S DAC chip
- For optimum performance the SABRE chip runs on a proprietary implementation of special developed firmware
- One motherboard based on a four-layer PCB with extra thick copper traces to achieve ultra-short signal paths with minimal wiring, to avoid electromagnetic induction of noise and to insure perfect grounding
- Discrete built power supplies for the digital and the analogue section using two toroidal transformers, last generation of ultra-low noise rectifier diodes and high quality audio operational amplifiers AD797
- Discrete built ultra linear power supplies for the heating power and for the high voltage of the tube output stage using two toroidal transformers with last generation of ultra-low noise rectifier diodes, double filter, audio grade resistors and capacitors
- Comprehensive noise regulation for all digital circuits
Jitter free operation by patented high performance algorithm
Integrated 32 bits volume control with a residual noise below -130dB for best performances even if at very low output levels
- On board output level setup to match different sensitivity of the direct connected power amplifiers
- PCM and DSD digital roll-off filters as well as asynchronous sample rate conversion of the Delta-Sigma DACs are user selectable in the set-up menu
- Voltage-compensated, ultra-low phase noise and low jitter crystal oscillators (clock) acts as master clock. Two separated clocks for sampling families of 44.1, 88.2, 176.4, 352.8 kHz and 48, 96, 192, 384 kHz
- DAC output stage with shortest possible signal path based on custom made amorphous audio transformers produced by Lundahl with first order discrete analogue filter for best THD and digital noise suppression
- True Class A discrete built analog tube output stage with zero negative global feedback for use with 6SN7GT tube family, including the CV181
- Separately powered USB chip by a ‚Äúquasi battery power supply‚Äù using a 1,0 Farad super-cap to avoid any distortion induced by the connected computer (no connection to the +5V powerline of the USB cable)
- USB input based on XMOS xCore audio chip with bit perfect transfer for 16bit, 24bit or 32bit data in PCM format up to 384 kHz including support for native DSD and DoP
4 Digital-Inputs: 1x USB 2.0; 1x true S/PDIF 75 Ohm BNC or, optional, true AES/EBU 110Ohm XLR; 1x S/PDIF RCA; 1x S/PDIF OPTICAL
USB input compatible with following audio formats via PC and MAC:
PCM: 44.1; 48; 88.2; 96; 176.4; 192; 352.8 and 384 kHz up to 32 bits
DSD (DoP): 2.822 MHz / DSD64, 3.072 MHz, 5.644 MHz / DSD128
SPDIF inputs (AES/EBU,BNC, RCA) compatible with PCM signals from 44.1, 48, 88.2, 96, 176.4 and 192 kHz, up to 24 bits. The OPTICAL input accepts music files with a resolution up to 24/96 kHz
- LCD Display with variable brightness, changing letter size for better reading from listening position
- Infrared remote control with direct function keys for volume, balance, absolute polarity, mute and setup menu
- No drivers required for LINUX or MAC OSX – USB Audio 2.0 driver available for Windows XP/Vista/7/8/10
In early February I picked up a large wooden box in the office of HiFi Statement. With the active support of Dirk Sommer, we both lifted the crate into the trunk of my car. After arriving at home and unpacking everything carefully, it stood before me: The ZeroUno DAC, which actually looks like a small tube amplifier. The ZeroUno is the product debut of the Italian audio manufactory CanEVER Audio.
Admittedly, when I first heard about the ZeroUno, I was somewhat skeptical. Today, as a new DAC is presented to the market almost daily, I hold a DAC as a debut of a company to be highly ambitious. To design a DAC is a highly complex matter. First, there is the digital to analog conversion in itself: Think only of the extremely complex, but (in detail) completely different approaches of Rob Watts in the Chord DAC or a Ted Smith in the PS Audio DirectStream DAC. Furthermore, there are also the analogue output stage, the power supply, and the digital inputs, as well as the USB input circuit. It is my firm belief that all these sections have a significant impact on the overall quality of sound.
The development of a high quality analogue output stage and the design of the digital part of a DAC are in principle two completely different engineering tasks. The analogue part of the circuit and, most of all, the power supply in a DAC do not get the necessary respect from most of the today‚Äòs electronic designers, from my view. Looking inside the cabinet of one or another DAC, I find myself thinking at how good that DAC would actually sound, if only it would be based upon a reasonably designed analogue circuit and/or power supply.
The design of a DAC with a high-end claim is therefore a big challenge in general, but especially for a small company such as CanEVER Audio. However, Mario Canever, the developer of the ZeroUno, is a full professional in digital as well as analogue electronics. A few weeks ago, I had the opportunity to talk with Mario Canever for an entire afternoon about the design of the ZeroUno. This DAC is “bursting” with a wide range of intelligent, highly interesting solutions. It takes care of the smallest details in signal processing, most of them way off the mainstream in engineering approaches, which are by no means any kind of “weird” solutions! Moreover, they are technically well thought-out implementations, which reflect the great experience of Mario Canever in the area of tube electronics as well as in digital technology.
To describe all the technical aspects of the ZeroUno is beyond the scope of this report. Therefore I decided to summarize my conversation with Mario Canever in a separate article (part 2 of this review), which will cover certain technical highlights of this DAC in much more detail. As I see it, the ZeroUno has really a lot to offer, and I would like to give our readers the opportunity “to look behind the scenes.”
Even at this early stage of the review, I have to say that I hardly know of any DAC designed so consistently in such a number of different engineering aspects. The ZeroUno is a truly professional and high-quality manufactured product with a rock-solid housing, encapsulated power transformers and a number of top-quality, partly audiophile components mounted at the printed circuit board level. This is not to forget the finish and the painting quality of the cabinet, which is of first-class quality too.
Listening to the ZeroUno DAC
For the listening test, I connected the analogue outputs of the ZeroUno DAC to my OMTEC preamp. Using the USB input, the DAC was “fed” by my JPLAY dual PC Setup running Windows 10 with Minim Server as a media server and kazoo in the latest version as control app for my iPad. The USB connection worked very well, even at the often critical switching between files with different sampling rates or data formats. This is an indication for a very careful implementation of the USB drivers and the USB input module. Even the change from DXD files in PCM format with 352.8 KHz to DSD files in DSD128 format was a shift that the ZeroUno handled without any problem.
Zapping through your music database without taking care about the different file types is pure fun. “Fun” is also the correct description for the mood I was in during the last few weeks using the ZeroUno. Please keep in mind: Before you start listening, allow the ZeroUno a certain “break-in” period. During this phase, the sound changes successively. At the end of that period, the sound “locked” down right, the room opened wide, the resolution increased, and the tonal match was detailed in the high notes, with bass that was very controlled. That DACs – regardless of the price – can sound very different is not a new insight. There are differences in the spatial picture. Too strong an analytical presentation will often “split” the soundstage into pieces, while extreme resolution in the midrange and in the higher frequencies “kill” the emotions during the listening. DACs present the lower notes in a variety of “textures” as well.