PS Audio AirLens and DirectStream DAC Mk2 Review

Digital Lens

The Digital Lens is the other chief part of the PS Audio AirLens design, with an emphasis on treatment of the digital signal. From the above website: “Digital audio signals rely upon critical stability in timing to sound their best. Relying upon the clock in your computer or the clock inside of a streaming interface is typically less than ideal. As network musical data enters a computer or streaming interface there is no clock associated with the data. Once collected, the master clock must be added so that your DAC can function properly. Inside the AirLens is PS Audio’s famous Digital Lens technology. Based on a variable RAM buffer, the data is collected and stored before being sent out to the DAC by a high-precision, low-jitter fixed clock.” As he was managing this review, I asked PS Audio’s Public Relations contact, Frank Doris, the editor of “Copper” magazine whether the phrase “the data is collected and stored” means it acts as a form of memory player, but it does not. The claim is that the AirLens’ design results in the cleanest, lowest jitter digital audio signal possible. The AirLens appears to be a galvanically isolated streamer with re-clocking.

On the underside of the AirLens is a series of dip switches that allow configurability for its use with non-PS Audio DACs. The dip switches are optimized for use with PS Audio DACs (from the factory they are all in the ON position), but those owning other DACs who wish to consider the AirLens will want to check out the unit’s operational flexibility. The dip switches control Frequency (48k, 96k, 192k, 384k), DSD (No DSD, DSD 64, DSD 128, DSD 256), DSD Mode (DOP or Native), Volume Control (Enable or Disable). The Owner’s Manual references dip switch 7 as for firmware updates and factory reset. I did not see dip switch 8 mentioned; I presume it is open for future use.

ROON is the user interface software that the AirLens was designed to run, but I was curious whether Audirvana would also work. I found that it did! In online discussion about use of Audirvana with the AirLens, I saw a caution that the variable volume control function of the AirLens may not work with Audirvana. Indeed, investigate optional software carefully, always ensuring to protect the equipment from incidents in which the full output is sent to the speakers.

Comparison between Airlens and Bricasti Design M5 network player

The diminutive AirLens’ looks like a miniature of the Mk2, its case having rounded edges, a glossy mirror black top, and the demur blue illuminated sine wave logo. It features only one input, an Ethernet cable from a LAN (local area network) and has only two outputs, SPDIF and I²S. The power cord is a standard 12V detachable IEC and I strongly recommend upgrading it. As the DirectStream DAC MK2 is not fitted with an integrated streamer, the AirLens was designed to partner with it for digital music supplied via the LAN. The particulars of the Bricasti Design M5 Network Player are covered in that review.

The AirLens and the M5 are both small, play digital streams and locally stored files, and are relatively affordable. They are also both bargains as regards digital sources, for they both are part of a new generation of streaming sources with performance ahead of the more expensive equipment I had been using just five years ago. As streaming devices, in the systems I have built in my recent search for a new digital front end, both outperformed that function in the Aurender A20, or the Aurender N20 when partnered with the DACs on hand. The AirLens and Mk2 together dramatically outperformed the Aurender units in the systems I have built. That is not to say the M5 or AirLens are superior to the Aurender units in an absolute sense, as I have not built all possible systems with them. I suspect that were a person to pair the Aurender units with a synergistic high-end DAC, the results may tip in favor of Aurender. But for persons limited to the affordable end of the hobby, both the Bricasti Design M5 and the AirLens are obvious choices.

The AirLens and M5 are quite alike in terms of the user experience but are apart when it comes to the types of outputs employed. The M5 has SPDIF, AES, and USB outputs, and the AirLens has SPDIF and I²S outputs. There is only one identical output between them allowing for a direct comparison, the SPDIF (coaxial digital). After disconnecting the M5, which had been connected via the USB output to the COS Engineering D1 DAC, my first listen to the same DAC using the SPDIF output of the AirLens gave me the impression that it was quite like the M5. The AirLens may have produced a bit thicker sound quality, that is, a bit riper.

It took several iterations of systems to find the best result for each of these sources in conjunction with the Mk2. As might be expected, the best result obtained with the AirLens was with an HDMI cable as the I²S connection to the MK2, and the best result with the Bricasti M5 was with one length of Iconoclast SPTPC Generation 2 XLR Cable acting as an AES cable. I have discussed in previous reviews that I have compared several purpose-built digital links to the Iconoclast interconnects and found that I often prefer the Iconoclast cable! In this comparison between the best that the AirLens and M5 could muster, I preferred the information retrieval and depth of soundstage of the AirLens and preferred the tonal richness of the M5. Both were gratifying and worthy of retaining as configurations to revisit.

Here was an instance where the purported best connection for two different components did not universally yield the best sound quality. When I reviewed the M5, Bricasti Design told me that the AES was the best connection. I found that if I employed the proper cables, I could make the USB connection perform superior to the AES connection. Similarly, PS Audio states the I2S is the best connection, but I was able to make the AES connection perform superior to it depending upon the cables employed. Both results are consistent with my long-term findings through building dozens of systems. Manufacturers have their favorite connections. but the audiophile should try all possible links because with any given cables being compared, one or the other may be superior. Similarly, a component’s “best” output may not be best given your particular components and cables. One simply must try all the iterations to know the outcome. Usually, the change in sonics between various components and cables is strong enough that the audiophile will have a clear preference.

20x upsampling and signal cables

As explained in the Owner’s Reference, the Mk2 upsamples all incoming signals to 20x DSD. The lengthy and technical introduction states in three instances that all signals are upsampled to twenty times DSD rate. The design is a matter of pride for PS Audio, calling it a “technological wonder” and claiming, “There has never been a better sounding DAC anywhere close to the price of DirectStream Mk2.” The introduction concludes, “We believe this new instrument will help further our industry, music and the faithful reproduction of music around the world.” The company is not shy of what it thinks of its DAC!

Regarding the upsampling and the multiple galvanic isolation methods internally, the owner is led to conclude that the cable used is less important, “DirectStream Mk2 is less sensitive to the vagaries of input source types and their level of jitter than most DACs made… a proprietary method of extremely fast sample-and-recognize technology is employed that reduces dependency on cables, jitter and the quality of the incoming source.” That is quite a statement to suggest the quality of the cables and incoming signal do not matter much!

Conversely, the “Getting Started” section recommends replacement of the stock power cord with a PS Audio upgrade AC power cord, “While the supplied cord is of good quality, it is recommended that you replace it with one of PS Audio’s matching PerfectWave AC power cords for optimum performance.” These comments are the antithesis of most component manufacturers I have reviewed, which stress the quality of source, interconnect, and speaker cables but downplay power cords.

Is PS Audio claiming the Mk2 is agnostic to incoming signals? The now-defunct Exogal’s Comet DAC, which also uses FPGA (field programmable gate array) technology to create its own algorithm, was said by the company to be agnostic to incoming signals. It was not entirely so. Similarly, already early on in my discovery phase, I have heard distinct differences in the operation of the Mk2 between sources and associated cables, such as the Bricasti Design M5 Network Player’s SPDIF output versus its AES output, or the AirLens’ SPDIF output versus the I2S output. I encourage owners to freely experiment with various types and brands of cables, and they should expect to hear differences between them. Persons serious about maximizing the connection should try no less than three cables in a bid to optimize performance.

Audioquest HDMI cables

I wished to hear the influence of an assortment of HDMI cables on the Mk2. I contacted Audioquest and their Director of Sales, Stephen Mejias, a former reviewer, who sent me 1.5m HDMI cables representing three levels of price and performance, Cinnamon, Thunderbird, and Fire Bird DBS.

The AirLens Owner’s Manual states that the shorter the I²S cable, the better the Mk2 will sound. An HDMI cable as short as .5m is said to be optimal. Knowing that some of my systems require placement of components a foot or two apart, I requested 1m HDMI cables, but Stephen sent 1.5m cables. It’s a good thing he did because the jacket of Audioquest HDMI cables is so stiff that twisting them into position is a serious endeavor. Even with 1.5m of length the cable barely allowed for a 180-degree twist for inserting the one end upright into the AirLens and upside down into the Mk2! Had the cables been .5 meter, I fear the physical restriction of twisting the cables may have prevented making the connection! I recall a similar topsy-turvy placement required when using the network (HDMI) connection between the Exogal Comet DAC and its complementary Ion PowerDAC. I intend to eventually try the Audioquest HDMI cables with the Comet and Ion to see if they influence its performance.

The Cinnamon HDMI failed the law of efficacy as compared to a nondescript HDMI cable. Were they not compared directly I doubt that I could identify them. The Thunderbird, which like the Cinnamon has copper conductors, introduced greater resolution and tonal color. The effect of upgrading the HDMI cable was now clear. The brilliance of the 20x DSD processing was beginning to take on new importance. Older tunes which had not been remastered were vivified. I was stunned by how immediate older tunes by Toto’s “Hydra” and Seals and Crofts “Diamond Girl” had become. The AirLens and Mk2 made such tracks seem like antiques pulled from a dusty corner which were cleaned and displayed in a well-lit room. The acoustic patina of these recordings stood out beautifully. I was concerned that the 20x DSD processing would make older tracks seem brittle, but they were more vibrant, like black and white images that had been colorized.

The Fire Bird DBS HDMI brought additional precision, I presume due to its silver coated conductors and higher level of carbon fiber noise control. I thrilled at the degree of refinement but was concerned that the combo was becoming edgy from too much treble emphasis. I tried five power cord combinations between the AirLens and Mk2 involving the Belden BAV Power cord, the Clarity Cable Vortex Power Cord, and the Snake River Audio Signature Series Cottonmouth Power Cord. Seeking not only more warmth but maximum refinement, the combo which locked the components and HDMI cables in place was the Cottonmouth Power Cord on the AirLens and the Clarity Vortex Power Cord on the Mk2. Altogether I had done about 8 cable changes to optimize the AirLens and Mk2, which is not atypical for new components.