Network Audio Players/Servers

Comparisons with Lumin's more affordable D2 music server/DAC solution [HFN Jul '20] are not especially instructive because the latter employs the Cirrus Logic (née Wolfson) WM8741 DAC while the P1 uses pairs of ES9028PRO converters. Maximum output is a healthy 5.8V from a transformer-coupled stage with a usefully low 18ohm source impedance (balanced XLRs) while the A-wtd S/N ratio is a very wide 118dB, via all digital inputs and over all sample rates. Distortion is exceptionally low too with just 0.00006-0.0003% achieved between 20Hz-20kHz at its peak output [see Graph 1, below]. Neither does Lumin appear to be using one of ESS's seven 'baked in' digital filters – instead, the algorithm, with a slow-roll off/linear phase profile, appears to be adaptive, responding differently to continuous and transient signals. Stopband rejection is 50dB (re. 20kHz at 48kFs) while the responses have a slightly early pre-Nyquist roll-off of –1.2dB/20kHz with CD/48kHz media and –5.1dB/45kHz with 96kHz+ media. Jitter, meanwhile, is vanishingly low at sub-10psec with all sample rates.

The Lumin P1 includes an equally impressive balanced analogue preamp. Gain is ~unity and the maximum input/output level is ~6V, achieving a low distortion of 0.0008-0.004% at 0dBV (20Hz-20kHz). Distortion increases at subsonic bass frequencies, from 0.004%/20Hz to 0.015%/10Hz and 0.15%/5Hz, presumably as a function of the output-coupling transformer [red trace, Graph 2, below]. The response also cuts off very abruptly below 3Hz but is otherwise flat to within ±0.2dB from 20Hz-20kHz before rolling away above 65kHz (–3dB) to –19dB/100kHz [black trace, Graph 1]. Note that the P1's 'CD de-emphasis' function is applied to its analogue inputs [dotted trace]. PM