May 23, 2015

  • PS Audio DirectStream DAC and Network Bridge, Part 2

    A Long Time Coming

    PS Audio, the reviews I've read and users comments all suggest that the DirectStream DAC (hereon after the DS DAC) takes 500 hours of use before it comes into its own. I can attest to the fact this is true.  At least 500 hours and I believe maybe longer.

    I'm going to depart from my usual Listening Impressions format and instead  describe the changes in sound that the DS DAC exhibited as time went by and the changes I made to fine-tune its performance.

    April 14-15, 2015
    Total Burn-In Time:  24 hours
    Although purchased from two different parties, both the DS DAC and Network Bridge arrive the same day and are connected to my system.  The first recording I listened to is Kitaro's Best of Silk Road.  This is a 96/24 DVD-A that has been copied onto an external hard drive (EHD) that was connected to my personal computer (PC) via its stock USB 3 cable and pushed to the Bridge/DAC via JRiver Media Center 20.  The first thing I noticed was that it sounded lower than what I'd been used to when listening to it via the Oppo 105D.  Both the 105D and the DAC were connected to my conrad-johnson CA200 integrated amp via identical 1M lengths of Acoustic Revive's RCA-PA interconnects so it wasn't a cabling difference.  A little research revealed that while the DAC outputs a 1.4Vrms signal, the 105D has a 2.1Vrms output.  This represents a 50% higher signal going from the DAC to the Oppo.  I then adjusted the volume level as best I could by ear since I do not an SPL meter.  My initial impression was that the DAC seemed more extended on top and perhaps a bit more airy.  At the same time, the recording played through the DAC sounded a little more relaxed and for lack of a better way of putting it, more lyrical as well.  Leading edge transients were sharper, more pronounced when the Oppo 105D was playing solo in an otherwise identical setup.

    I believe that differences I was hearing has much, if not all, to do with how SACDs (and therefore DSD recordings) sound to me versus LPCM recordings.  The latter would include Red Book CDs and DVD-A recordings.  Since the DAC initially converts all incoming signals, regardless of their original format, to 10X DSD and then downsamples to 2X DSD, this is what I was hearing.  These differences between the two formats continued, in varying degree, throughout my time with the DAC.

    On the second day the system started to experience skips and pauses during playback which was very annoying.  In the past, these sometimes plagued playback with the 105D but not to the same degree.  I suspected the culprit may have been the Bridge's outdated firmware.  Nevertheless, percussion instruments were more real and natural although also a bit softer through the DAC.  It seemed to me that there was more of a "feel" for the skin/drumhead with the DAC playing.

    April 16-21, 2015
    Total Burn-In Time:  168 hours
    Used a single XLO Signature 3.1 RCA interconnect to port the 105D's output directly into the DAC even though the cable was not specifically designed for this purpose.  The 105D's coaxial output is user selectable LPCM to 48/96/192 resolution or Bitstream.  I used the LPCM 192 and Bitstream settings and had a small preference for the latter but would be hard-pressed to consistently tell one from the other in a (shudder) blind test.  The coax connection was at least as good, if not better, when listening to the same material and there were no sonic hiccoughs (skips and pauses) when doing so.

    A big negative:  when listening to my set top box (STB) that's connected to the 105D with a Mapleshade HDMI cable and in turn via coax to the DAC, voices had a very unnatural echo quality to them when played at higher volume levels that was absent when the DAC was out of the chain.

    Playback of 44/16 FLAC files may be the DAC's forte with an almost reference level presentation.  The 105D solo, in comparison, is more edgy and digital sounding.  Images are larger with the 105D.  The DAC, on the other hand, presents smaller, denser images which are more easily distinguishable from each other as a result.


    The next installment will include the download of the Pikes Peak firmware, changing the DAC's power cord, and the introduction of footers (feet?) into the mix.

Comments (2)

  • I'm glad you kept track of how much usage the unit was getting. I get so much gear in, and often under time constraints, that I don't keep track of usage. I am in a rush to document features, take pictures, do some burn-in, and finally, time permitting, doing some listening.

    Seems like others weren't kidding, when they said the DS really does need at least 500 hours of playing time, before it opens up, and fulfills its potential.

  • In order to hasten the burn-in process, I left the DAC on continuously and when I wasn't actively listening to it, I would mute the amp but still have a source, such as the set top box running through it.

    That makes calculating usage just a matter of subtracting one date from the date it arrived.

    At this point, I shut the unit down (actually it's in standby mode) when not listening to it.

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