Outboard DACs

Aside from the mis-directed switching of its digital filters, a 'feature' the Element X2 shares with the X-Sabre 3 [HFN Apr '22], this new iteration of the X series (Hardware v1.5, Firmware 1.0.0, Build 050) delivers state-of-the-art results. While some early implementations of the ESS ES9038PRO DAC, including Matrix Audio's X-Sabre Pro [HFN Nov '17], had higher levels of correlated jitter than might have been expected, this was solved in the Element X [HFN Jan '21] and squeezed still further in the X2 – in asynchronous mode – to ~10psec (all sample rates, all inputs). Just two sidebands remain, at ±1.946kHz and a PSU rectification mode at ±100Hz, but these are truly minuscule [see Graph 2].

The X2's maximum balanced output is fractionally higher than that of the Element X (4.44V vs. 4.33V) and the A-wtd S/N ratio fractionally wider too at 116.4dB, though the moderate 96ohm source impedance is unchanged. Low-level linearity pushes deep below typical recorded music levels and is good to ±0.1dB over a full 110dB dynamic range, suggesting an effective resolution in excess of 19-bits. Distortion remains extremely low at 0.00008-0.00015% at 0dBFs (20Hz-20kHz), holding to a mere 0.00015-0.00055% over the top 30dB of its dynamic range [see Graph 1, below] – all figures that are outside the envelope of most amplifiers and certainly all loudspeakers. I discuss the response and time domain behaviours of the digital filters on p65 while the stopband rejection of the 'real' Fast Minimum, Fast Linear, Apodising, Brickwall, Hybrid, Slow Minimum and Slow Linear types are 73dB, 81dB, 82dB, 82dB, 84dB, 18dB and 14dB, respectively. The latter two filters are best deployed with higher (96kHz and above) sample rate files. PM