Romanian manufacturer Rockna have announced the  new Wavedream DAC series will be available in the UK soon. There are 2 main models : Edition (featuring Rockna RD-1 discrete DAC modules) and Signature (featuring Rockna RD-0 discrete DAC modules) with each version being available in single ended or balanced configuration.ROCKNA_wavedream_dac1

In addition to the Femtovox clock system, both Edition and Signature benefit from a new discrete output stage, have an improved power supply section and in addition have dedicated sections for digital and analogue 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.

The RD-1 module has a 26-bit ladder structure, while RD-0 is a 27 bit ladder structure. Both are FPGA-based, meaning they have their own (upgradable) firmware. A custom solution, freed from the limitation of the available chipsets, comes into place, allowing them to design and build from the scratch an entire digital audio system.Rockna_DAC_3

All building blocks of the Wavedream DAC concerning digital processing are built entirely on a single piece of programmable silicon – an FPGA . With an FPGA, the internal hardware architecture could be described by a piece of software. When upgrading the Wavedream with new firmware, you actually changing its hardware. This system allows flexibility, obsolescence protection and lets Rockna improve the sound of your DAC by changing its internal architecture, or to add new features, or improve the existing ones.

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 rat which the guys at Rockna say is the rate they found to be optimal for analogue performance of the DAC modules. The digital filters are made with the combined effort of 58 DSP blocks, resulting into in 15 GMACS of processing power. The developed filters are unique say Rockna. They avoid standard Nyquist rate filters as Rockna thought they did not “provide the expected performance for the DAC”. After lots of mathematical simulations and careful listening tests, they have created a custom Parks-McClellan upsampling filter. There are three variations available on current firmware: linear, minimum and hybrid phase. Rockna_wavedream2

Finally, the last stage of the signal path is the analogue output stage. 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), Rockna engineers 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 converters overall performance.

Both DACs will be available from BD AUDIO in the UK soon.


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