Network Audio Players/Servers

Equipped with a quad-core Celeron processor, the EX is rated by Antipodes as a fine renderer but with a reduced server capability compared to the CX with its Intel i7 on board. However, the 'entry-level' EX has the advantage of offering a one-stop solution for first-timers thanks to its 2V (line level) DAC output. This is not a Cirrus, TI or ESS DAC but an integated function of the motherboard's Realtek audio hub. This is the first time we have tested a 'mobo' audio output, and its performance is none too shabby. Although Realtek specifies the part as 24-bit, this refers to wordlength handling rather than achievable resolution because the 96dB A-wtd S/N ratio and ±0.8dB error in linearity at –100dBFs suggest a practical performance of around 16 bits. However, what is mainly 'white' noise is subjectively preferable to a more granular noise populated with digital spuriae and, indeed, this also serves to bury any correlated jitter to <10psec at all sample rates from 44.1kHz to 192kHz [see Graph 2]. Clock accuracy, meanwhile, is within Class 1 specification at –27ppm.

There is some (analogue) stress on the op-amps over the top 20dB of the EX's dynamic range where 2nd-15th harmonics push up to a modest 0.011% through bass and midrange and 0.016% at high (20kHz) frequencies. Lowest distortion is achieved at –15dBFs (0.0016-004%, 20Hz-20kHz), but all frequencies follow a very consistent 'pattern' with changing level [see Graph 1, below]. The linear phase digital filter provides 53dB of stopband rejection (re. 48kFs) and offers a very flat reconstructed response, extending to ±0.06dB up to 20kHz with 44.1/48kHz media, –2.1dB/45kHz with 96kHz files and –2.8dB/90kHz with 192kHz digital sources. PM