Network Audio Players/Servers

Although the datasheet for Pascal's U-PRO 2S Class D amplifier module(s) tallies with AVM's own 2x140W/8ohm specification the PSU configuration endows both the module, and AVM's CS 2.3, with vastly higher output under both single-channel and dynamic conditions. Thus 2x145W/8ohm becomes 240W/8ohm and 345W/4ohm, one channel driven, and 248W, 524W, 475W and 250W into 8, 4, 2 and 1ohm loads for 10msec at <1% THD [see Graph 1, below]. So, in the 'real world', the CS 2.3 will achieve far higher SPLs with any given speaker than the brand's simple specification might suggest. Otherwise, overall gain is very high at +48.1dB and the A-wtd S/N ratio a little below average at 82dB (re. 0dBW), though this is an innocuous white noise. The 'character' of the CS 2.3 is also shaped, as a matter of design, by both distortion and response, the former a very low 0.0025-0.0065% from 20Hz-2kHz before increasing to 0.05%/10kHz and 0.19%/20kHz.

The CS 2.3's ESS9038-based DAC/preamp stage is very 'clean', offering a wide 110dB A-wtd S/N ratio, very low <15psec jitter (all sample rates, 24-bit data), and resolution good to within ±0.1dB over a full 100dB dynamic range. Distortion is a fabulously low 0.0001-0.0006% at peak output (20Hz-20kHz) and lower still at 0.00009-0.0003% over the top 20dB of its range [see Graph 2]. The 'Steep' and 'Smooth' digital filters are both linear phase types offering a consistent 100dB stopband rejection and near-identical response of ±0.01dB (20Hz-20kHz) with CD and 48kHz sources. Only with 192kHz files is there a small difference (–2.3dB vs. –6.9dB/90kHz, respectively). PM