Network Audio Players/Servers

With a peak level (0dBFs) digital input the PSD 3100 HV will offer a substantial 18.9V balanced output at full '99' volume, however distortion is just shy of clipping at 0.8% and only settles back to a consistent 0.0014%/1kHz at volume settings of '89' and lower. This represents a 'standard' 6V balanced output from a 23ohm impedance where distortion holds to 0.0014-0.0017% (20Hz-20kHz) and falls to a low 0.00013-0.0004% over the top 20dB of its dynamic range [see Graph 1, below]. The A-wtd S/N ratio is a respectable 114.8dB (for double-differential PCM1795 DACs) while jitter is held to a low ~10psec over all sample rates.

The six in-house upsampling filters use the latest coefficients last seen in the DAC 200 [HFN May '22]. FIR Long and Short are linear-phase types while the Bezier polynomials are minimum-phase filters. FIR Long [black traces, Graph 2] trades (unnatural) extended pre/post ringing for low phase distortion, a comprehensive 102dB rejection of aliasing images, and flat responses that reach out to –0.0dB/20kHz, –1.0dB/45kHz and –3.7dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. 'FIR Short' [red] has much reduced pre/post-ringing but also a very limited 7.4dB rejection of out-of-band images and a steep treble roll-off of –3.6dB/20kHz. The mixed 'Bezier/IIR' interpolation filter [cyan] behaves like a slow roll-off minimum phase filter with no better suppression of stopband images than FIR Short, slightly increased phase distortion and a +0.8dB/13kHz treble peak. The NOS (non-oversampling) modes 1 and 2 [green traces, Graph 2] offer almost perfect time domain behaviour – no ringing – but a rolled-off treble of –3.5dB and –3.2dB/20kHz, respectively, with CD/48kHz media. PM