Outboard DACs

Comparisons with the full Vivaldi 'stack' [HFN Feb '13] and Vivaldi One [HFN Feb '18] show small, steady improvements in the evolution of dCS's Ring DAC and analogue technology. The analogue output buffer still has a fabulously low, cable-agnostic 480mohm source impedance and offers a maximum variable output up to 5.88V – ideal for driving power amplifiers directly. The A-wtd S/N ratio is now fractionally higher at 117.1dB and low-level resolution good to ±0.3dB at –120dB. Distortion remains as low as ever through bass/midrange at <0.00009% over the top 20dB of its dynamic range and is even fractionally lower in the APEX at 20kHz where THD falls between 0.0001-0.0003% over the top 30dB [see Graph 1, below, and note the expanded 0-140dB Y scale]. Correlated jitter looks to have increased to 120psec (48kHz/24-bit data) but that is only because the ±5Hz, ±7Hz, ±9Hz, etc, sidebands are now exposed by the elimination of random jitter/phase noise.

Channel separation is >120dB (20Hz-20kHz) while the frequency response(s) depend on your choice of filter, all six delivering a ruler-flat ±0.05dB (20Hz-20kHz) with CD media albeit with variable stopband attenuation (108dB, 57dB, 17dB and 7.3dB, Filters 1-4, respectively). Filter 5 is a minimum phase type with significant post-ringing and Filter 6 a linear phase type with lower amplitude, but more extended, pre/post ringing [orange/purple traces, Graph 2]. Filters 1-4 are linear phase for all sample rates and offer responses of –22dB/45kHz, –0.7dB/45kHz, –29dB/39kHz and –10.6dB/ 45kHz, respectively, with 96kHz media and –13dB/90kHz, –7.3dB/90kHz, –23dB/77kHz and –17.9dB/90kHz [black, red, cyan and green traces, Graph 2], respectively, with 192kHz files. PM