Network Audio Players/Servers

In practice, the DAC-Z10’s DAC/analogue stage bears little relation to that in the ES9039SPRO-based DMP-A10 [HFN May ’25] but, rather, looks closer to a double-differential version of that in the DMP-A8 [HFN May ’24] with its use of two AK4191EQ/AK4499EXEQ upsampling/noise-shapers and DACs (one set per channel). The uplift in performance pushes at the state-of-the-art – despite being subjectively academic – with distortion now falling from 0.00003-0.00025% (DMP-A8) to 0.00002-0.00025% (20Hz-20kHz re. 0dBFs), requiring a shifted 0dB to –140dB Y scale [Graph 1, below]. Moreover, the A-wtd S/N ratio improves from 116dB to 118dB here with low-level linearity tightening still further to within ±0.05dB over a full 110dB dynamic range.

The AK4191EQ modulator includes six filter coefficients, including two linear- and minimum phase types (both Fast and Slow). The Fast filters have the same –0.3dB/20kHz, –1.8dB/45kHz and –4.6dB/90kHz responses with 48kHz, 96kHz and 192kHz media, respectively, with a similar 104dB stopband rejection. The Slow filters trade a limited 8.5dB rejection and –8.6dB/20kHz, –10.9dB/45kHz and –13.8dB/90kHz responses for minimal ringing/time domain distortion. Otherwise, the minimum phase fast ‘Mix’ is a hybrid type while the linear phase ‘Switch’ filter is a NOS type, the latter best suited to 96kHz+ files.

Jitter is almost entirely suppressed and unaffected by the ‘FPGA/Clock Shaping’ option in the Audio menu. Via the T8’s isolated USB output this falls to 4psec in the DAC-Z10 [black spectrum, Graph 2], increasing slightly to 7psec, with some additional low-level spuriae, via I²S [red spectrum, Graph 2]. PM