Another question I had when investigating the Nyquist was related to the DAC chip implemented in it: ESS9018S. While that is a technically very advanced D/A conversion IC, it can be obtained e.g. through the rather good Auralic Vega (or my stylish Gemini 2000 for that matter) for less than 1/5th of the cost. And the Auralic implementation is already quite nice, as it has been voiced after the world-class analogue Neve recording console. That is however where the commonality ends.
First of all, it is a bit of a simplification to judge the sound of a DAC based on the onboard IC, as the actual implementation and customizable filtering affects the sound quite a bit. There is a sound signature though, if the ESS9018 does all the conversion work like D/A processing, PLL and digital filtering. But already in case of e.g. an Oppo or Auralic implementation the DACs do sound a bit different IMHO. Audible differences can be achieved in the basic D/A chip implementation and by customizing the filtering options as Auralic have done.
Second, as the ESS9018S has eight D/A circuits those can be allocated in different ways to serve the conversion process. E.g. in the Vega four D/A converters have been allocated to each channel. Alternatively, they can be assigned to serve one or both channels, i.e. a stereo or mono setup. This is is a specific feature of this D/A chip.
In comparison, in the Nyquist there actually are two ESS9018S ICs, i.e. one per channel with eight D/A circuits each, running in a double-mono configuration. The benefit of that is that their outputs are combined to lower the noise floor, randomize any conversion errors and create a balanced output signal. This does affect the conversion accuracy and noise floor quite significantly.
Further, as the Nyquist is a hi-end DAC and there is only so much that can be achieved with an off-the-shelve DAC implementation, the actual sound processing in the Nyquist is done completely outside the ESS9018S. As a matter of fact, only the actual D/A conversion is handled by the Sabre and all other of its advanced functions have been turned off. This is as better sound quality can be achieved through custom implementations. In case of the Nyquist a customized PLL, a dedicated DSP with digital filters and a separate re-clocking circuit have been developed in-house by Brinkmann. To minimize jitter, the clock does have very low phase noise and is sitting next to the D/A chip. Even the clock’s power supply is derived from the tubes, as the Telefunken PCF803’s operate as a power filter to supply cleaner power. The level of effort in this design is also exemplified through the fact, that there are 11 power supplies inside the DAC module alone. And as such, in the Nyquist the DAC chip does not affect the sound pretty much at all, as it is only used for the actual D/A conversion and all sound related processing and filtering are done in custom processors.
Going back to the beginning of this posting, we can see that while the same IC is used in more affordable products, there are fundamental differences in the implementation. To the extent that they actually do have rather little in common and correspondingly the products’ sound signature is very different.
This is also where I disagree with John Atkinson’s Auralic Vega review: the Vega is for sure a nice DAC, but in my book it does not represent anything anywhere even close to a Class A+ rating, i.e. a reference level product. While the Vega is nice, there are products that are so much better, namely e.g. the Brinkmann Nyquist, the Berkeley Ref II or Mike’s new MSB Select II, that they simply do not belong in the same class. Frankly speaking, I think the guys at Stereophile appear a little lost in the digital world at times or at least their Recommended Components list seems a bit incomprehensible.
Concluding from my study of the matter, the ES9018S as implemented in the Nyquist, is really not your Dad’s Buick.
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