PS Audio DS Memory Player/PW DirectStream DAC CD player/DAC Lab Report

Hi-Fi News has kept pace with the development of PS Audio's bespoke transport/DAC solution since the original PerfectWave combination was launched nearly a decade ago [HFN Aug '09]. The adoption of Ted Smith's oversampling/DSD DAC technology, which operates at 112.9MHz (20x 'DSD64') and downconverts data to 5.6MHz/1-bit (DSD128), was unveiled in the first DirectStream DAC [HFN Aug '14], and this 2018 version shows clear upgrades. The impulse response still shows extended pre/post ripples in the time domain and, because this is a DSD converter, there remains an increase in (white) noise through the audioband itself, reducing the A-wtd S/N ratio to a '16-bit' 96.4dB. Jitter is effectively masked, with just a pair of sidebands at 70psec (S/PDIF)/62psec (I2S) exposed [see Graph 2].


Distortion vs. 48kHz/24-bit digital signal level over a 120dB dynamic range (1kHz via S/PDIF, red; via I2S, black and 20kHz via S/PDIF, purple; via I2S, cyan)


High resolution 48kHz/24-bit jitter spectra (S/PDIF, red; I2S via Memory Player/USB drive, black)

I pointed out in our original review that the DS DAC's bandwidth was limited to –16.7dB/50kHz regardless of sample rate and this has been redressed here – the DAC still has a slightly rolled-off bass (–0.15dB/20Hz) but HF extension now reaches out to –1.05dB/45kHz and –9.7dB/90kHz with 96kHz and 192kHz media, respectively. Moreover, its high frequency performance is markedly improved in other areas: ultrasonic requantisation noise is reduced by at least 25dB (60-100kHz) while 20kHz distortion is down from 0.006% to 0.003% at –10dBFs and 0.01% to 0.004% at –30dBFs. The transformer-coupled output increases THD at low frequencies (though 0.1%/20Hz is much reduced over earlier models). Interesting, THD over the top 20dB of the available dynamic range is fractionally lower (~1dB) via the Memory Player/DAC's I2S connection (which retains its clock) than if driving the DAC directly via S/PDIF [see Graph 1]. PM

Maximum output level / Impedance: 2.83Vrms / 145-149ohm (XLR)
A-wtd S/N ratio (S/PDIF / I2S): 96.4dB / 96.3dB
Distortion (1kHz, 0dBFs/–30dBFs): 0.015% / 0.0019%
Distortion & Noise (20kHz, 0dBFs/–30dBFs): 0.031% / 0.0042%
Freq. resp. (20Hz-20kHz/45kHz/90kHz): –0.2 to –0.1dB/–1.1dB/–9.7dB
Digital jitter (48kHz via S/PDIF / I2S): 70psec / 62psec
Resolution @ –110dB : ±0.1dB
Power consumption (Player/DAC) : 11/28W (1W standby)
Dimensions (WHD, each) / Weight (total) : 430x100x360mm / 33kg
Price(s): £6000/£5500

PS Audio
Boulder, Colorado
Supplied by: Signature Audio Systems
07738 007776