Digital Processor Reviews

As it turned out, the silence wasn't the result of a hardware or firmware flaw. Rather, it pointed to the need for greater care in optimizing my computer settings—greater, that is, than the level of care required by most PCM-only USB processors, the relative simplicity of which had lulled me into a false sense of expertise. During a conversation with Paul McGowan I learned that I needed to: open my iMac's AudioMIDI Setup window; highlight the left-column choice for the PS Audio DAC; change the source default sampling rate from 44.1 to 192kHz; and remove from the master-channel "Mute" box a check mark that, oddly, reappeared more than once during the review period.

After that, I had to: call up the Audio System screen within Audirvana Plus's Preferences menu; change the Preferred Device to the PS Audio DAC (that option appeared automatically on hitting the Change button); and, most important, change "Native DSD Capability" to the option for "DSD over PCM Standard 1.0." (Per McGowan's suggestion, I also checked the option for Integer Mode.) After that, the system passed a bit-perfect throughput test. More to the point, it played music.

A final setup note: Given the choice, I always prefer the sound of my system with an active preamplifier—the passive approach seems to me sorely lacking in drive by comparison—so I didn't try using the DirectStream to directly drive any of my amps. That said, I found that the higher of the converter's two volume ranges best suited my system.

Listening
Arguably the most notable feature of the PS Audio DirectStream is its ability to convert everything to DSD, so that's just what I used to test it: everything—including downloaded DSD files, DSD files made from vinyl, high-resolution WAV files, CD-resolution AIFF files, even MP3 files. (The DirectStream did a fine job with the MP3 streams from the websites of WKCR and other stations.) With virtually all programme, as my favorite old-school British reviewers called it, the DirectStream distinguished itself as a superbly musical source component with excellent pacing, flow, correctness of pitch relationships, and the like, as well as a consistently smooth and slightly laid-back sound, especially when compared to competing high-end converters.

Unsurprisingly, DSD files sounded especially fine through the DirectStream DAC. "Tiny Dancer," from Elton John's Madman Across the Water (from MCA 2016), had clarity, color, and as much touch as one could expect from a 1971 studio rock recording in which virtually every instrument was subjected to generous levels of compression. Indeed, Caleb Quaye's consistently tasteful guitar embellishments popped nicely from the mix, while the pedal steel guitar of Cochise alum B.J. Cole shimmered and shone nicely behind the other instruments. John's lead vocal was realistically punchy and present, but lacked the excessive bite I've heard through other gear.

"St. Thomas," from Sonny Rollins's Saxophone Colossus (from Prestige 7079), also worked well, with good color—but slightly deficient texture—from the tenor sax and a fine drum sound, and with reasonably good touch. Good tactile qualities also characterized the DirectStream's way with Mahler's Symphony 1, played by the Budapest Festival Orchestra under the direction of Iván Fischer (from Channel Classics CCS SA 33112). The soft initial timpani strokes about 2:44 into the first movement had good startle factor, as did the even softer first taps on the bass drum a little after 9:00, and plucked strings and harp all had good touch and impact. The orchestra's first crescendo, at 7:26, was a little bloodless; the sound was considerably less forward than with the Luxman DA-06 DSD converter (which I reviewed in the July 2014 issue), enough that I often found myself inching up the volume control, hoping for just a bit more impact.

"Lonesome Tears," from Beck's Sea Change (from Geffen B0004372-01), was musically and emotionally compelling through the DirectStream. That said, the textures of the string samples were slightly smoothed over compared with the way they sounded through the Luxman converter, the latter also allowing more snap and impact in the drums and the glockenspiel-like electronic percussion. Similarly, the Luxman did a better job of getting across the breathy quality of Sarah Watkins's voice in "Sabra Girl," from Nickel Creek's This Side (Sugar Hill)—although the DirectStream presented the music with an exceptionally fine and very analog-like sense of musical flow and momentum.

The same set of qualities—excellent musicality, clear and reasonably colorful if slightly reticent and overly smooth sound—followed the DirectStream to the realm of PCM files large and small. In conductor Daniel Myssyk's recording of Hindemith's Escales Romantique (from the Fidelio Musique sampler Escales), the chamber orchestra and piano both sounded just a bit distant and a shade soft through the DirectStream. My first impression was that the PS Audio was rounding off the attack components of notes to the detriment of their sonic physicality—yet there was excellent forcefulness in the plucked strings behind the piano in the second portion of the work's second movement, and I was impressed by the subtle and altogether lifelike manner in which the piano sound became bigger and more physically commanding as the intensity of the playing increased. This music was ultimately very satisfying through the DirectStream, even if it didn't sound quite as forward as I expected.

Solo piano music was also consistently involving through the DirectStream, as I found with the musically raw, live-in-the-studio recording by Jorge Bolet of Liszt's perversely fascinating arrangement of Wagner's Tannhäuser Overture (AIFF ripped from CD, RCA 63748-2). Here, again, the DirectStream seemed a bit rounded off and lacking the immediacy of, say, Bricasti's fine M1 DAC, which visited recently, and through which I could easily hear into the very blackness of the recording studio's natural reverb. Yet it was only when listening to the file through the DirectStream that I found myself physically responding to the music, nodding vigorously in response to the piece's many emotional peaks. And "Pharaoh's Dance," from the 40th-anniversary reissue of Miles Davis's Bitches Brew (AIFF from CD, Columbia/Legacy 88697 702742), was a delight: the most rhythmically insistent reproduction I've heard of this PCM file. The sound was free from digital edge, and offered not only great color in the trumpet and reeds, but excellent force and touch in Lenny White's and Jack DeJohnette's drumming and in Don Alias's congas. And Harvey Brooks's electric bass was colorful, impactful, and altogether badass.

Listening with new firmware
Apparently, my thoughts on the DirectStream's slightly distant, less-than-fully-textured sound were shared by someone at PS Audio: Unbidden, Paul McGowan contacted me in early June, alerting me to a user-installable firmware update aimed, he said, at "opening up" the sound—and, concomitantly, enabling the DAC to accept PCM files of sampling rates up to 352.8kHz.

The new firmware (v.1.1.4) arrived the next day on an SD card; installation was a simple matter of powering down the converter, inserting the card in the rear-panel slot, powering the unit back up with the card in place, and, after reinitialization, removing the card. Anyone could do it.

To get a handle on the update, I went back to Beck's "Lonesome Tears"—and was pleasantly surprised by a very audible increase in texture and touch. The PS Audio DirectStream maintained its slightly distant sound compared to that of the Luxman and other converters, but its excess smoothness had been replaced with a greater degree of textural nuance and detail. I was already impressed by the DirectStream's ability to play music more compellingly than most D/A converters of my experience; here was the refinement that put its sonic presentation in the first rank, as well.

I relistened to many of the selections cited above, and heard improvements in all of them. Across the board, attack components of notes were now more distinct—as a surprise bonus, I could more easily hear the differences between correct and incorrect output-signal polarity—and imaging "precision" was enhanced. As Beatrix Potter's Sally Henny Penny would say, "Something for everyone!"

Conclusions
Some digital products seem intended to stave off obsolescence as long as possible. And some digital products have a distinct point of view. PS Audio's PerfectWave DirectStream DAC is a little bit of both, and I find myself admiring the combination.

In these early days of DSD streaming, it should come as no surprise that the industry's digital-audio specialists are rolling out some rather large guns—and at prices often high enough that the target audience may, at first, be limited to only the most serious DSD and SACD stalwarts. So it goes here: The DirectStream is an original and very forward-thinking product that is priced accordingly, but not unfairly. It's beautifully made, insofar as I can see, and pleasant to use. Perhaps best of all, as I've already seen, it's very easily upgraded.

Time will tell if and when these levels of performance, flexibility, and luxury will become available for less than $6000. But today, for those who've waited for a computer-friendly DAC that offers, with every type of music file, the best musicality of which DSD is capable, the PerfectWave DirectStream may be in a class by itself.