Lansare Rockna Wavequest DAC

In week-end-ul care tocmai a trecut, am fost prezent la un eveniment mai mult decat important pentru piata audio din Romania. Intr-o atmosfera prietenoasa, in cadrul showroom-ului Audioconcept, a fost lansata versiunea finala a DAC-ului high-end Wavequest, produs de Rockna Audio. Evenimentul in sine a fost interesant atat prin prisma faptului ca s-a testat varianta finala a unui DAC cu o tehnologie de varf, cat si faptul ca este primul produs de acest calibru proiectat si fabricat integral de o firma romaneasca.

Evenimentul in sine a fost unul destul de relaxat, s-a ascultat muzica, am stat la un pahar de vorba (unii la mai multe :)), s-au schimbat opinii si cel mai important lucru, am cunoscut oameni cu adevarat pasionati de muzica si tehnologie. Sper ca in viitorul apropiat sa se organizeze mai des astfel de evenimente, unde, pe langa auditiile in sine, se schimba informatii cu adevarat valoroase.

DAC-ul este o completare a liniei high-end Wavequest, primul produs din acesta gama fiind Wavequest Trasport, lansat in 2009 si apreciat de catre utilizatori ca un produs de top mondial.
DAC-ul nu este construit in jurul unor cip-uri de conversie de genul BurrBrown, Wolfson sau AKM, care indiferent de calitatea implementarii limiteaza conversia la calitatile dac-chip-ului folosit.
In Wavequest au fost implementate module Platinum de la MSB Technology si tehnologie FPGA, ceea ce confera dezvoltatorului o mult mai mare libertate de miscare, mai multe posibilitati de utilizare si implementare.

Modulele de dac discrete de la MSB ofera performanta de conversie de top in tehnica R2R, fiind printre putinele optiuni care suporta o rata de sampling de 1,5 Mhz, in timp ce toata programarea fpga-ului (adica tot frontend-ul digital, cu toata procesarea de rigoare), e proprietara Rockna. Puterea de calcul cumulata a matricii de filtre implementate (accesibila prin exoticul sub-meniu “Matrix” este in jurul valorii de 20 GMACS (Giga-macs). Prin comparatie sistemele bazate pe DSP (Meridian, Anagram) nu depasesc 1 GMAC ca putere de calcul. Nu in ultimul rand, prin update de firmware se poate modifica substantial (in bine) conversia dorita.
Sistemele folosite in testarea combo-ului Rockna au fost si ele cu adevarat de exceptie. Echipa Audioconcept a pregatit doua camere de auditie, cu doua sisteme de bugete diferite, in acest fel cei prezenti au putut sa-si formeze o opinie mai completa asupra potentialului noul DAC.

Sistemele de test:
Sistemul 1:

• Rockna Wavequest Transport si Wavequest DAC
• preamplificator – Audioresearch Ref 3
• amplificator de putere – Audioresearch VS 115
• boxe – Martin Logan Ethos
• cablu digital – HDMI Chord
• cablu dac / pre / power – made by Audioconcept in colaborare cu Neotech (conductor argint pur pe occ, multipla ecranare, dielectric teflon)
• cablu boxe – Neotech Sahara

Sistemul 2:

• Rockna Wavequest Transport si Wavequest DAC
• preamplificator – Audioresearch 40TH Anniversary Reference
• monoblocuri – Audioresearch Reference 210 Monaural
• boxe – Martin Logan Summit X
• cablu digital – HDMI Chord
• cablu dac / pre / power – made by Audioconcept in colaborare cu Neotech (conductor argint pur pe occ, multipla ecranare, dielectric teflon)
• cablu boxe – Neotech Sahara

Pot spune fara sa gresesc prea mult, ca toti cei prezenti au apreciat Wavequest DAC in mod foarte pozitiv.Sper ca in viitorul apropiat sa se organizeze mai des astfel de evenimente, unde, pe langa experienta auditiei in sine, partea de socializare are un loc foarte important.

In incheiere va atasez comunicatul de presa primit de la Rockna Audio cu aceasta ocazie:

Sound of the matrix numbers – Rockna Wavequest 1.5 Mhz DAC
Numbers:

1.5 Mhz sampling rate
3.4 Million gates
4 K taps
14 digital filter settings
15 ultra low-noise regulators
20 GMACS computing power
24 bit true R2R dacs
2.5 years of work

Enter the matrix

Everybody is familiar with upsampling. 96k, 192k, 384k… very rare 768k.
Wavequest pushes the limit further to a whopping 1,5 Mhz sample rate which feeds the
true ladder DAC modules for an absolute smooth waveform reproduction.

This becomes possible due to all-new Rockna Digital Engine (RDE) which takes
care of all the functions, from stream receiving and decoding, digital pll, ram based
reclocking, digital filters, complete user interface. No off-the-shelf parts are used.
Instead, a single 3.4 million gates FPGA (a very powerful customizable integrated circuit)
performs all the RDE functions.

One of the main functions of the RDE is the digital PLL / RAM based reclocking.
The exact sample rate of the incoming signal is precisely measured inside the RDE and
audio data is isolated from the stream, and stored for a few seconds inside a RAM
memory. Any input frequency variation is filtered preventing jitter to leak into the
system. With this filtered value an ultra precise master clock is programmed in real time
with 38 bit precision. From this clock are directly derived the I2S clocks for the DAC
modules, which are fed with the data stored into memory. This mechanism allows total
isolation of the input clock from the only clock that really matters – the one entering the
DACs.

Prior to the DACs, the audio data enters the matrix – which is an array of
selectable digital filters. The user can select the interpolation type (sin x/x or linear), the
interpolation order by using single or combined filters, and the filter response by
switching between minimum phase and linear, or using any combination of these two.

The computing power involved in digital filtering outperforms by an order of
magnitude any off the shelf available chip. While 128 or 256 taps are common in filters
today, the RDE makes use of an optimum 4k of taps. The performance of these filters
lead to -160 dB stopband attenuation and nearly non-measurable passband ripple.

The sound? You are invited to judge yourself.