Disc Players

Testing the Varèse DAC with 16-bit CD and (DSD64) SACD via the new Transport necessarily shows up slight differences versus 48kHz-192kHz/24-bit streams [HFN Feb ’25]. The maximum 5.9V output and sub-1ohm balanced source impedance are obviously unchanged but the wide 118.1dB A-wtd S/N ratio with both CD and SACD also holds true. However, there are minuscule differences in distortion. SACD matches the 48kHz/24-bit result of 0.00003% over the top 10dB of the Varèse’s dynamic range (re. 1kHz), while CD is fractionally higher at 0.00008% [see Graph 1]. The 20kHz figure increases from 0.0001% (48kHz/24-bit) to 0.0003% with CD and to 0.075% with SACD, this latter figure entirely dominated by the swell of ultrasonic requantisation noise that persists above 20kHz with DSD64 encoding.

Differences in low-level resolution are significant for while 16-bit CD manages +0.1dB at –100dB and –0.9dB at –110dB, SACD betters even the 24-bit result of ±0.2dB/–120dB with mere errors of +0.1dB/–120dB and a phenomenal –0.2dB/–130dB. CD jitter is governed by the 116psec J-pattern residual (and just 5psec at ±100Hz) while SACD has a mere 25psec at ±2.43kHz [see Graph 2, below]. Freq. response(s), stopband rejection and time domain behaviour all depend on your choice of dCS’s six custom digital filters. F1-F6 all deliver a flat ±0.04dB/20Hz-20kHz response with CD, and with stopband artefacts suppressed to –125dB, –35dB, –12dB, –6dB, –127dB and –120dB, respectively. All filters are linear phase except the minimum phase F5. Filter F1 delivers the flattest –0.5dB/80kHz and –8.4dB/100kHz response with SACD, with F2 at –8dB/80kHz and F3 at –23dB/80kHz. F4 is the most attenuated, rolling away early at –23dB/40kHz. PM