Outboard DACs

The Vega DAC has steadily evolved since its first-generation platform was tested [HFN Jan '14] with improvements in processing speed, functionality, file format handling and technical performance. Not that the 'Vega G1' was especially tardy, offering distortion as low as 0.00004-0.0004% from 20Hz-20kHz over the top 30dB of its dynamic range together with a full 115.8dB A-wtd S/N ratio. The Vega G2.1 still employs a 'tweaked' ESS Sabre DAC and Class A 'Orfeo' analogue output stage but the latter has been refined to offer a higher 4.65V output (from 4.1V) and a slightly wider 116.5dB A-wtd S/N ratio, but the impressively low 'drive any interconnect/line input' 0.25ohm source impedance remains untouched. In practice while the Vega G2.1's distortion still drops to as low as ~0.0001% over the top 30dB of its range (20Hz-20kHz) its peak level distortion is higher at 0.0013-0.005% [see Graph 1, below], either as a result of the analogue stage's higher gain or as a result of Auralic's 'sound tuning'. Either way, these distortion figures are still 100-1000x lower than the average loudspeaker at 90dB SPL, so it's always worth keeping some perspective!

Although Auralic specifies its own master clocks for the Vega G2.1, the jitter rejection performance of these ESS DACs is already well proven. Digital jitter was vanishingly low in the Vega G1 and it remains so here with a correlated figure of <15psec across all LPCM sample rates and inputs (the Vega G1 lacked the G2.1's network connection). In the analogue domain, the Vega G2.1 also impresses – the R-2R ladder volume control maintains a tight 0.02dB channel balance while stereo separation is a full 135dB/1kHz through the Orfeo gain stage. PM