Wavedream DAC

ROCKNA's current flagship in digital audio reproduction. It has the right ingredients to produce a sound that will honor its name. The ingredients, innovations, technology and features which employ in the Wavedream DAC, push the limits of performance, design and sound quality to the top tier and make it a world class product.

SOFTWARE DEFINED ARCHITECTURE

All building blocks of the Wavedream DAC concerning 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 its internal architecture, or add new cool features, or improve the existing ones.

CUSTOM DIGITAL FILTERS

The Wavedream DAC 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, which found 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. These unique filters are developed, from a Parks-McClellan equi-ripple combined with a raised-cosine type, after countless mathematical simulations and careful listening tests. There are three variations available on current firmware: linear, minimum and hybrid phase. They are highly optimized filters, offering stunning performance with a decent amount of taps (2k), 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 hybrid phase filter has a combined response between both linear and minimum phases, exhibiting very low overshoot before the impulse.

FEMTOVOX CLOCK SYSTEM

The Wavedream DAC is designed with 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.

D/A CONVERSION

For the effective D/A conversion stage, Rockna developed their own 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 algorithm 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 audio dac. The output of the dac modules is un-buffered, allowing maximum transparency and natural sound reproduction.

EXTRA MENU FEATURES

A series of useful features can be found on the Wacedream DAC menu.

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 - 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 refer 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 DAC benefits internally from a carefully studied and full symmetrical layout. Shortest signal paths and proper design of the clock tree were the main guidelines. All off-board connections are made with LVDS standard for lowest interference, high speed and minimal jitter. The transformer section is internally shielded to prevent internal EMI leakage. The chassis is entirely made of black anodized aluminum with a maximum front plate thickness of 20 mm. Switches are black ruthenium finish.

Wavedream DAC available in several versions

Wavedream Edition - Single Ended Wavedream Edition - Balanced

Wavedream Signature - Single Ended* Wavedream Signature - Balanced*

OUTPUT STAGE

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), and 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 there are dedicated sections for digital and analog areas. Total 3 separate transformers, and all power supplies are low noise linear - no switch mode power supplies, are used whatsoever. A total of 20 linear regulators have been employed inside the dac. Special dedicated attention has been made to the dac modules regulators – which are designed from the scratch for low impedance and ultra-low noise.

DIGITAL INPUTS
Coaxial S/PDIF: 24 Bit, 44.1-192 KHz PCM; DoP DSD64
AES/EBU: 24 Bit, 44.1-192 KHz PCM; DoP DSD64
USB 32 Bit, 44.1-384 KHz PCM; DSD64-256
HD-Link1 (LVDS): 32 Bit, 44.1-384 KHz PCM; DSD64-256
HD-Link2 (LVDS): 32 Bit, 44.1-384 KHz PCM; DSD64-256
OUTPUTS (Wavedream Edition)
THD+N (at - 6dB): 0.003% or -90 dB
S/N ratio (0 dB): 122 dB
Dynamic range: 122 dB
Output impedance: 0.5 ohms
Max. voltage: 6.6Vpp(SE); 13.2Vpp(XLR)

 

OUTPUTS (Wavedream Signature)
THD+N (at -6db): 0.0008% or -102 dB
S/N ratio (0 dB): 132 dB
Dynamic range: 132 dB
Output impedance: 0.5 ohms
Max. voltage: 10Vpp(SE); 20Vpp(XLR)
Miscellaneous:
128x64 yellow oled display, dimmable in 8 steps
4 control switches
IR remote control
Firmware upgrade via usb
Dimensions: 440 x 360 x 90 mm
Weight (net): 7.8 Kg
Voltage: 120 V/240 V
Manufacturer's Warranty: Limited 3 Years (Details as per Owner's Manual)