ROCKNA AUDIO is the mother company of Audiobyte. It’s founder Nicolae Jitariu is regarded as a digital wizard having designed for PS Audio, Goldmund and MSB. Rockna has two products in it’s portfolio; the Wavedream Net a CD/DVD/Blu-ray transport with Roon and in-built storage and the Wavedream DAC available with both single ended and balanced XLR outputs.

 

If you are looking for high-end audio as it should be, you may be in the right place.

Let’s bring back innovation, consistency and common sense applied to design and technology.

Nicolae Jitariu
Founder Rockna Audio


WAVEDREAM DAC

THE SOUND YOU EVER EXPECTED, 

AND BEYOND.

We are proud to present our current flagship in digital audio reproduction. We believe it has the right ingredients to produce a sound that will honour it’s name. In the good tradition established by it’s predecessor, the Wavedream continues to push the limits of performance, design and sound quality. The ingredients, innovations, technology and features of the product are presented below.

SOFTWARE DEFINED ARCHITECTURE

We always thought that high-end audio should be everything about innovation. Playing around with off-the-shelf available chips is fun and certainly a good and economic way to produce good sound. But once you want to design a cutting-edge product, the off-the-shelf approach doesn’t apply. Naturally, a custom solution, freed from the limitation of the available chipsets, come into place, allowing us to design and build from the scratch an entire digital audio system.

All building blocks of the Wavedream DAC concernig digital processing are built entirely on a single piece of programmable silicon – a FPGA . With a FPGA, it’s internal hardware architecture could be described by a piece of software (actually, a very complex one). When upgrading the Wavedream with new firmware, you actually change it’s hardware. This system allows great flexibility, obsolescence protection and let us improve the sound of your dac by changing it’s internal architecture, or add new cool features, or improve the existing ones.

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FEMTOVOX CLOCK SYSTEM

The clock is the heart of a digital reproduction system. It’s accuracy and jitter levels are critical in regard of sound quality. Only a very good clock system can make the way to the analog sound on the output of your DAC. If the clock is flawed, digital harshness will occur and the analog feeling of the music will be severely altered. Apart from the performance of the clock itself, equally critical is the construction of the clock tree (the clock distribution architecture) inside the DAC. The jitter amount that really counts it’s not only the performance of the clock itself – but the clock which actually enters the dac and is used for conversion – let’s call it the conversion clock. The conversion clock that enters the dac section relies on the clock tree, which is usually not just routing, but in most cases conditioning, altering it’s quality. A poorly designed clock tree can degrade significantly the clock quality entering the d/a section, even if the source clock has great performance.

With these facts in mind, we designed for the Wavedream an advanced clock system called the femtovox. With femtovox in place, one is assured that only extremely small amounts of jitter are present at the dac conversion clock input. It’s unique architecture employs that conversion clock is directly synthesised at the dac input, without any conditioning, giving constant jitter performance at any sample rate. The conversion clock is controlled with 1 ppb precision, while exhibiting about 300 fS of jitter. The smallest jitter figure in the world? No. The smallest jitter figure where actually matters? Probably.

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CUSTOM DIGITAL FILTERS

The Wavedream upsamples any material with a fixed rate of 16x. The dac modules will decode the digital stream with a rate of 768Khz, or 705.6Khz, respectively, according to input sample rate. We found this rate to be optimal for analog performance of the dac modules. Behind this simple multiplication factor (16x) lies a huge processing power. The digital filters are made with the combined effort of 58 DSP blocks, resulting into a impressive figure of 15 GMACS of processing power.

The developed filters are unique. We avoided standard Nyquist rate filters as not providing the expected performance for the dac. After lots of mathematical simulations and careful listening tests, we have created a custom Parks-McClellan upsampling filter. There are three variations avaialble on current firmware: linear, minimumand hybrid phase. They are highly optimized filters, offering stunning performance with a large number of taps (5k), and they are different in regard of impulse response. For the linear phase, the ringing energy (Gibb’s overshoot) is equally split before and after impulse. Minimum phase type shows all this energy after impulse, while our special hyrid phase filter has a combined response between linear and minimum, exhibing very low overshoot before the impulse.

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D/A CONVERSION

For the effective D/A conversion stage we developed dedicated dac modules called RD-0 (used in Signature – 27 bit structure) and RD-1 (used in Edition – 26 bit structure). Modules themselves are complex pieces of technology, sharing a discrete sign-magnitude hybrid ladder topology, driven by a complex algorythm which is embedded into their own FPGA. Therefore the dac modules firmware is updatable both performance and feature-wise. Currently RD-0/1 can sustain a maximum sample rate of 6 MHz, which is the industry’s maximum sample rate specified for a audio dac. The output of the dac modules is un-buffered, allowing maximum transparency and natural sound reproduction.

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OUTPUT STAGE

Finally, the last stage of the signal path is the analog output stage. It’s contribution to final sound is of extreme importance. Designed from the scratch to work with converter modules RD-0 & RD-1, the output stage is totally discrete and acts as a high-speed buffer. Made entirely with through-hole components (non-smd), we combined j-fet & bipolar devices into a class A design, with a closed-loop output impedance of under 1 ohm and equivalent input noise as low as 1nV, as a perfect match for the converter overall performance.

THE POWER SUPPLY

Naturally we have dedicated sections for digital and analog areas. There are 3 separate transformers, and all power supplies are low noise linear - no switchmode power supplies are used whatsoever. There are a total of 20 linear regulators inside the dac. We dedicated our attention to the dac modules regulators – which are designed from the scratch for low impedance and ultra-low noise.

EXTRA MENU FEATURES

On the dac menu can be found a series of useful features. Let’s take a short walkthrough.


  • The preamp feature - The Wavedream has a 256 steps volume control which allows direct connection of a power amplifier. The volume control has 0.5 dB steps for a fine resolution setting. 

  • The phase select feature – the user can change the absolute phase of the output signal. 

  • The filter select feature – discussed above. The filters can be switched off for NOS operation. 

  • The clock setting – there are 2 modes of the digital PLL response, stream and local. Please reffer to the clock technical document under the technology section for more information. 

  • Dither – to improve R2R ladder linearity, ultrasonic dither is applied on the last 4 bits from the digital 24-bit word.

CONSTRUCTION DETAILS AND INTERNAL LAYOUT

The Wavedream benefits internally from a carefully studied, full symmetrical layout. Shortest signal paths and proper design of the clock tree were our main guidelines. All off-board connections are made with LVDS standard for lowest intereference, high speed and minimal jitter.

The transformer section is internally shielded to prevent internal EMI leakage. The chassis is entirely made of black anodized aluminium with a maximum fronplate thickness of 20 mm. Switches are black ruthenium finish.

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How does it sound?

BASS

The bass is incredible as it has exploding impact, excellent detail, goes very deep when it should and seems to be controlled by an iron hand. Also, it seemed very natural to me and I often had the impression I felt the material the drums were made of. I could feel the drums in my body, and no, I wasn’t using speakers, just headphones.

MIDS

One of the best mids I have ever heard in my life. All is at superlative with this DAC. Every instrument is alive and kicking and the voices are out of this world. You can hear every tone in the singer voice, every emotion, passing it to you, making you feel the song and the emotions he wants to transfer.

TREBLE

As you expect the treble is top notch as well. The sparkle is crystal clear and full of life and extension.

TRANSIENT RESPONSE

This is another breathtaking aspect of the Wavedream as it has very fast and natural decay and incredible attack.

DETAILS & MICRO DETAILS

With the Wavedream you discover a lot of interesting new sounds in your favourite songs, things you may have never heard before. Besides the obvious things you will hear improve like instrument & voice extension, sometimes an instrument playing subtle in a deep layer you have never heard before, you may hear a car passing by the recording studio or the artist scratching his face. Some say that don’t like analytical sound. Well, the good news is all those details come in a very natural way and I don’t consider the sound to become analytical. Nothing is pushed in front by force, all comes naturally. This helps passing the emotions from the song to the listener with better efficiency, as you can hear the whole extension of the instruments and all the tonalities and effort of the singer’s voice.

SOUNDSTAGE, INSTRUMENT SEPARATION, LAYERING & POSITIONING 

The instruments are extremely well separated and layered. Even in the most crowded passages you don’t feel that the layers blend in, as the Wavedream seems to decompress them in a much larger scene, leaving a lot of air between the instruments. I can’t even refer to stereo presentation any longer as 3D or holographic would be a much more accurate description. Also, the soundstage is incredibly spacious and airy.

DYNAMICS & MICRO-DYNAMICS

This is another amazing aspect about the Wavedream. I often noticed some instruments in the orchestra that are meant to be subtle, it manages to do this but still gives them life. You can feel every instrument however subtle it is and however further in the back it may be.

ENERGY & TACTILITY

Some of the features from above result into something I love very much. I am referring to the tactility of the sounds. I can feel the guitar like I am plucking it myself, I can feel the drums and the material they are made of, the voice singing into my ear and sometimes feeling the warmth of the breath, the violin and cello chords vibrating. So every sound has it’s energy, however subtle it may be. You can imagine that when the song wants to be energetic, the Wavedream makes it explode with energy.

TRANSPARENCY

It transposes you in your favourite concert hall or it opens the window directly into your music and helps you lose yourself into your favourite songs.

(reproduced from Headmania Review)

 

Hi-Fi + Review

THE EAR Review


WAVEDREAM NET

 

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LOCAL, LAN AND DISC MEMORY TRANSPORT

The Wavedream NET is a unique product which adds together a high performance audio server and a latest generation, memory-based cd transport. You can enjoy your cd collection, internal storage playback or latest streaming experience from only one machine. The NET is naturally the best complementary source for the Wavedream DAC over the HDlink(I2S) connection.

 

FPGA-BASED HIGH PERFORMANCE AUDIO

The NET is built around a powerful digital audio core, which streams all audio data into a large RAM buffer. The audio data is clocked out after a ultra-low phase noise masterclock, making the machine close to a ideal source. The powerful FPGA engine takes care in exclusive mode of the disc playback, which is totally separated by the server side. Also, the FPGA contain a large number of DSP units which can be very effective in real-time processing of audio streams, saving lots of processing power from the server’s side CPU.

 

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ISOLATED MUSIC SERVER

The audio server embedded into the NET is galvanically isolated from the audio side to prevent any kind of unwanted noise to leak into sensitive areas. We carefully balanced the server power consumption with it’s processing power. A very large processing power means more complex and power-hungry CPU’s, which are not necessarily a good thing for audio reproduction. The server software is based on a lightweight version of Linux, which gives our quad-core processor enough headroom to run many audio services in parallel.

 

LINEAR-ONLY POWER SUPPLY

One of our design goals was to stay away from a switch-mode power supply, which can have potentially higher noise and possible harmful effects when placed near sensitive audio circuitry. Therefore, there are only linear power supplies inside the NET, including power for the server side. At first sight one might be tempted to use high-powered CPU, following the principle “the bigger, the better”. Actually, a large processing power is not always necessary and it comes with benefits of lower noise, simpler architecture, lower radiated EMI and of course, lower power consumption.

 

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SOFTWARE FEATURES

The WDNET software pack is a dynamic collection of audio services. They are controlled over a simple and straightforward web interface which can be accessed from the phone/tablet or a local computer. Currently following services are supported

  • Roon Server – recommended control app: Roon remote
  • MPD Server – recommended control app: MPD control, MPDroid
  • Upnp/DLNA
  • Airplay
  • HQplayer NAA
  • Disc ripping – FLAC, WAV, MP3 on local storage

UPDATE FEATURE

Digital audio is a very dynamic field which can quickly evolve just in a matter of months. The webserver interface along with services can be easily updated with just a simple click from the interface.

TECHNICAL SPECIFICATIONS

  • PCM 44.1K-384K, DSD64-DSD256
  • Local storage (ssd only): 1 TB or 2 TB; on special request 4TB
  • Inputs: ETH, USB mass storage
  • Outputs: SPDIF, AES/EBU, BNC, 2xHDlink(I2S), USB

 

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