Our review of the ‘first’ DirectStream DAC MK2 [HFNJun ’23 and pictured below] highlighted an unusually – unexpectedly – high level of requantisation noise from PS Audio’s proprietary crunching of all input data, up to 705.6kHz and DSD256, into a ‘pure’ bitstream. This noise was not simply ultrasonic (which brings its own unpredictability with different amps and loudspeakers) but also in-band, pulling the A-wtd S/N down to a below-average 92.5dB. Inspired by this revelation, or not, PS Audio has recently announced a significant firmware update dubbed ‘Mount Massive’, claiming ‘…audible noise has been lowered by 10dB, and ultrasonic noise is reduced by 30dB’. Is the true potential of the DS DAC MK2 now realised?
In practice, the A-wtd S/N is improved by 4-5dB while ultrasonic noise has been suppressed by 25dB at 60kHz.
This commentary on the actual measurements of Massive installed on a MKll was included in their new review of the Air Lens.