Dual ES9028Pro DAC
The D57 is based on two ESS ES9028Pro chips to deliver high audio performance in stereo and mono. These converters use the HyperStream II ESS architecture to achieve a wide dynamic range and low THD+N. The DAC also supports high resolution files, up to 32bit 384kHz and DSD/DXD via its USB and I2S inputs. Furthermore, offering two converters instead of one improves both the dynamic range (DNR) in mono at 135dB and the THD+N at -120dB. For comparison, the ES9028Pro duo provides a better 3dB DNR compared to an ES9028Pro alone.
Moreover, in mono mode, the unit has one converter per channel, which improves crossover (frequency separation) and therefore provides a wider and more precise sound scene.