PS Audio DirectStream DAC
Input: 2x I2S, Coax S/PDIF, AES/EBU, Toslink, USB, Network Bridge slot
Output: balanced XLR, single-ended RCA
Dimensions (W x H x D): 14” x 17” x 4” (36cm x 43cm x 10cm)
Weight: 31 lbs (19 kg)
Availability: Online and through Authorized Dealers
A Direct Stream
There was a lot of information surrounding the launch of PS Audio's DirectStream DAC. The company released a series of videos on YouTube (see videos) explaining some of the technology behind their new DAC, featuring the DAC's designer Ted Smith. There was also a white paper (see paper) that went into some detail regarding how the DirectStream handles DSD which is, according to them, unusual. Essentially what we're looking at and listening to is an FPGA-based D to A design as opposed to a chip-based solution that leaves DSD in its native 1-bit format. But that's not all.
"Put DSD into DirectStream, you get DSD. Put PCM into DirectStream, you get—DSD" so says the company and that DSD solution is 1-bit, not multi-bit and everything is upsampled to 10x DSD to boot. From the manual, "All sample rates supported are synchronously upsampled to 10x the standard DSD sample rate and then back down to double rate DSD (2 * 64 * 44.1kHz). There’s no need for other clocks to interpret the inputs, no matter what their sample rate, because of the instrument’s single clock architecture." The DirectStream uses a single master clock from Crystek Corporation which they claim helps reduce jitter. I actually recommend checking out the manual if you are interested in additional technical aspects of the DirectStream's's design (see the manual).
The DirectStream DAC will accept I2S, Coax, XLR Balanced (AES/EBU), Toslink, USB, and the PS Audio Network Bridge module. The USB, Coax, AES, and I2S inputs can handle up to double rate DSD and 24/192 PCM while the Toslink input is limited to 24/192, no DSD. Outputs include single-ended RCAs and balanced XLRs. You can also opt to add PS Audio's Network Bridge module which effectively transforms the DirectStream DAC into a network player.
The front panel sports a nice color touch panel display that shows the incoming file's bit and sample rates, the active input, volume level, and phase. Those last three can be controlled via the touch screen or through the included remote. There is also a two step level control to better match your pre/amp which can be set on the touch screen's setup menu or via remote. You can also dim the display and change the name of the inputs which is a nice family-friendly feature.
The rounded-cornered case is wrapped in a nice matte combination of aluminum and steel with a very shiny "hand painted, hand polished piano black high density material" top panel. All around I'd say the DirectStream DAC exudes understated quality. I used the DirectStream DAC with my Macbook Pro so no drivers were required. Windows users need to download and install the PS Audio drivers to take advantage of anything over 24/96 and DSD. I used Audirvana Plus and Pure Music 2 with the DirectStream via XLRs to my usual Pass INT-30A/DeVore The Nines setup.
How Direct Can A DAC Be?
Purity. That's the word that came to mind when I first played the DirectStream and that's the word that remained attached to it for the duration of this review period. There was an amazing sense of purity to the DirectStream's way with music as if everything and anything extraneous had been stripped away. This quality was evident regardless of the sample rate or format, and applied equally to PCM and DSD. There was a very pronounced sense of clean, clear, and pure sound reproduction.
Taking a more detailed view into its sound, I'd also say that the DirectStream DAC sounds very controlled throughout the frequency spectrum including fit 'n full bass response that is at once controlled and hefty. If there was an area that I found the DirectStream DAC to diverge from other DACs I enjoy its with timbral complexity and midrange richness. A DAC like the comparably priced Luxman DA-06 (see review) puts more meat on music's bones and I would not object to someone saying it sounds more analog as compared to the DirectStream DAC. Compared to the less expensive Auralic Vega (see review) I found that the Vega also sounded more colorful and more lit up up top. I also would not argue if someone were to suggest that the DirectStream DAC was more neutral in a positive way taking personal preference into account.
I never felt the DirectStream DAC to be edgy or unnaturally bright even though the amount of resolution it extracts from your music sources is remarkable. There is an important difference between resolution and detail, the latter sometimes a product of exaggerated upper frequencies which ultimately leads to listening fatigue. This was certainly not the case here even with CD-quality sources. I also spent a lot of time listening to music sourced from the Qobuz Hi-Fi lossless streaming service and it was all pure pleasure. What about DSD? While I would not say the DirectStream's way with DSD is revelatory, it is very musical and involving. That near 3D quality I've come to associate with DSD was clearly present as was DSD's rich, smooth character.
I do not have any way to test the DirectStream's I2S input, but I did take its other digital inputs for a test spin including Coax using the Resonessence Labs Concero HD as a USB - S/PDIF converter. Here PCM and DSD sounded very much like what was coming out of my MacBook Pro via USB. Clean, clear and resolute. Using the Moon MiND's AES/EBU output connected to the DirectStream also proved sonically rewarding. The MiND appears to offer even more resolution as compared to my MacBook Pro and this pairing made for a very rich and revealing combo. The MiND does not support DSD but PCM recordings of all stripes from CD-quality on up sounded just lovely. I felt there was ever so slightly more overall weight to the presentation with this pairing as compared to USB from the MacBook.
PS Audio claims the DirectStream DAC's volume control is transparent with no loss of resolution, "100% bit-perfect volume", and my own listening confirmed this claim. Even at low listening levels, music retained its character with no sense of the sound washing out. For those people looking for a direct-to-amp DAC/Digital Preamp, consider the DirectStream a solid contender.
I will also mention that I greatly preferred the DirectStream DAC when paired with the AudioQuest Diamond USB cable. I initially used the Light Harmonic Lightspeed USB cable and found the overall performance to be a tad flat. This perceived flatness was not a factor with the Diamond USB cable and I would recommend this particular pairing for DirectStream buyers.
I also received a firmware update (rev. 1.1.5) late in the review process that adds the ability to play back 352kHz files and gave it an afternoon's worth of listening time and I'd say it sounded as if there was a 'presence' control that someone turned up. The presentation was now bigger, wider, and also sounded as if it took a step or two forward in my room. To my ears these are all steps in the right direction allowing you to better hear into the recording for a more engaging experience. I was curious about what this firmware update actually adressed and got this response from PS Audio, "Less jitter but primarily we opened the input sampling filter from 40kHz to 80kHz and that made the biggest change."
A Clear Stream
I enjoyed my time with PS Audio DirectStream DAC and found its sound highly resolving, pure, and...direct. If you're looking for a DAC and digital preamp that is both well-built and sonically transparent, the DirectStream DAC should be on your short list.
Also on hand and in use during the DirectStream DAC review: Auralic Vega