Network Audio Players/Servers

Rapidly becoming the Class D solution of choice, Hypex's Ncore module, and particularly the 150W variant, is delivering reliably high performance in a wide variety of audiophile separates [most recently the Mola-Mola Kula, HFN Oct '21]. The 'fingerprint' is becoming familiar – it offers the rated 2x150W/8ohm by the skin of its high speed transistors, and up to 2x280W/4ohm, while the technology allows for little or no dynamic headroom, realising 150W, 290W, 275W and 193W at <1% THD into 8, 4, 2 and 1ohm loads, respectively. Maximum current is limited to ~14A [see Graph 1]. Gain is a sensibly moderate +34dB (balanced input), but the 82dB A-wtd S/N (re. 0dBW) falls about 5-6dB short in the Evo 150 courtesy of two spurious idle tones at ~1kHz and ~2kHz. Bass/midrange distortion remains very low at 0.0006% up to 10W, increasing to just 0.004-0.007% at 100W, though THD does pick up above 10kHz to 0.025%/20kHz/10W, in line with the gently tailored response of –0.6dB/20kHz to –6.5dB/100kHz.

Also thoroughly tried-and-tested is the ESS Sabre ES9018K2M DAC, implemented here with its fixed linear phase digital filter. This trades pre- and post-ringing in the time domain for an 89dB stopband rejection and flat, extended responses that reach out to –0.12dB/20kHz, –0.9dB/45kHz and –2.4dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. Measured at a 2V (preamp) output, low-level resolution is true to within ±0.2dB over a 100dB range and the S/N is a wide 106.5dB (no idle tones here). Distortion, too, falls to a low 0.0002-0.001% (20Hz-20kHz) over the top 20dB of its range [see Graph 2, below] while jitter is very well suppressed at less than 25psec, across all sample rates and all digital inputs. PM