Outboard DACs

The Element X2 retains the very capable headphone amp described in our review of the Element X [HFN Jan '21] and also includes the same ES9038PRO DAC, however the firmware looks closer to that seen in the more recent X-Sabre 3 [HFN Apr '22]. This popular ESS-sourced DAC chip offers designers seven alternative digital filter modes – five with a 'fast' (sharp) roll-off and two with 'slow' (gentler) treble roll-offs. Once again, however, what you select from Matrix Audio's menu is not necessarily the filter you think...

Selecting 'Fast Minimum' actually invokes a filter that performs like 'Brickwall' while 'Slow Minimum' yields a 'Slow Linear' filter and 'Fast Linear' delivers an 'Apodising' filter. Further down the list, 'Slow Linear' is actually the 'Hybrid' option; 'Brickwall' is 'Fast Minimum'; 'Hybrid' is 'Slow Minimum' and 'Apodising' is 'Fast Linear'. The 'real' Fast Minimum, Fast Linear [black, inset Graph], Apodising and Brickwall all have sharp roll-offs [the Hybrid filter, blue, has an early roll-off and some in-band ripple], with Slow Minimum [red] and Slow Linear affording gentler treble roll-offs, reduced 'ringing' but poorer stopband rejection. With 48kHz files the responses reach out to –0.0dB, –0.0dB, –0.8dB, –3.9dB, –12.2dB, –5.0dB and –3.4dB/20kHz, respectively. With 96kHz media, the 45kHz response limits are –0.0dB, –0.3dB, –7.4dB, –23dB, –14dB, –6.9dB and –4.8dB while, with 192kHz files, the 90kHz response limits are +0.1dB, –0.2dB [black], –7.3dB, –13.8dB, –23dB [blue], –6.8dB [red] and –4.8dB, respectively. PM