PS Audio AirLens and DirectStream DAC Mk2 Review

Shell Lift

By offering the Shell Lift feature and others like it, the company is giving the public a powerful tool in shaping the sound of the audio system!

Optimizing a system is not a matter of guesswork but manipulation of the variables. The audiophile who wishes to truly maximize performance and enjoyment of the system will try all system configurations regardless of preconceptions as to the result. Regularly, I am stunned by an unexpectedly great result from trying an alternative configuration, and working with the Ground Lift and Shell Lift features of the Mk2 is one such example.

My experience with the Mk2 has been delightful not only as it is the first DAC with an I²S link that I have tried, but also the first to incorporate three settings affecting the grounding, allowing the user to select which, if any, to employ. The Input Ground Lift influences the incoming signal, and it can be lifted on any of the inputs including optical. The ground lifts influencing the output of the Mk2 are distinguished as Output Ground Lift (for RCA connections) and Shell Lift (for XLR connections). Using the arrows and center button of the Control Ring I was able to quickly navigate the menus and select which of the ground lift options I wished to activate. The ability to lift the grounds of both the RCA and XLR outputs is valuable to me, as I build many systems utilizing both type of outputs simultaneously. If only one or the other could be adjusted, it would be a pity. Having both available invigorates my system building with options for yet higher performance. For instance, since I send the RCA signal from the Mk2 to the Perlisten subwoofers, they also benefit from the Ground Lift of the RCA outputs.

What a fabulously potent set of controls! If the 20x DSD could be likened to a microscope delving into the music twenty times deeper, the grouped grounding options allowed for another 10x in resolution. I am not saying literally ten times, but figuratively enabling another leap in resolution and appreciation of the finer things of listening, literally finer things. The fine, or minute, characteristics of the presentation popped out of the background when these settings were employed. As when we focus on the filigreed work on a piece of jewelry, the grounding settings take the listener in for a closer examination of the music and allow appreciation of details not previously noticed. The wonderful thing about such close listening is that it in no way destroys appreciation of the whole but rather enhances it.

These ground lifts caused a fabulous James Webb Space Telescope (JWST)-like depth of the sound field that made a million little details pop like stars in black space! That is the sort of event that makes music scintillatingly real sounding. Now all the pummeling of the incoming signal could be appreciated. A space telescope system is not a simple device, point and shoot tube with lenses. It has banks of processors to crunch the incoming light stream to focus and yield supreme resolution, which the viewer of the photo sees and appreciates. Consider the digital engine of the Mk2 to be the bank of computers crunching the data and the ground lift settings to be a set of lenses that open or close to convey the signal. Together, they are a fabulous combination of technology that create impressive images of music.

There is a phrase used in audiophilia, hearing deeply into the music. It sounds like a gimmicky concept that has no reality – until you experience it. It is not a punctiliar phenomenon but is on a spectrum, as are the other parameters of performance such as tonal balance, imaging, and transients. Every system has a combination of these and other attributes that fall somewhere on the spectrum for each one. Hearing deeply into the music is when the resolution and imaging is so profound that one can hear vastly into the performance, sensing things that seem quite distant or buried in the sound stage and which were previously occluded, obscured. The ear takes it all in, from the close performer to the distant queues of the recording space. JWST makes photos of the previous generation Hubble Space Telescope seem less impactful. Having all the grounding lifts engaged makes the stock, grounded settings seem less impactful.

PS Audio is correct to boast about the Mk2 and the various grounding options are a notable reason for such pride. They are the unexpected bonus of the DAC, a suite of powerful sound conditioning circuits that take the DAC beyond expectation. When I first read the introductory comments in the Owner’s Reference about the DAC, they seemed boastful, arrogant. The full experience of the Mk2 shows that the company is not arrogant; they have built a truly incredible DAC!

Exciting listening sessions

I wish for my audio system to thrill me, not lull me to sleep. I become excited about a product that moves my listening sessions into uncharted territory of performance, and the AirLens with the Mk2 were leading me onto new listening ground. Some of my test tracks were Mandy Moore’s “Every Light”, Zedd’s “Papercut”, Michael McDonald’s “Reflections”, and Kirk Whalum’s “Living for the City.” These tracks covered the spectrum from quiet vocals to heavy electronic to acoustic Jazz. The AirLens and Mk2 presented each piece of music as I wished, vibrant, information rich, and highly engaging.

The 20x DSD breathes new life into older digital recordings that have not been remastered. My nostalgia listening takes me back to songs like “I Can See Clearly Now” by Johnny Nash, “If” by Bread, and “I’m Not in Love” by 10cc. When played on NOS (non-over sampling) DACs, these songs sound thin, tired. The gulf in recording studio methods between the 1970’s and today can be heard in the lackluster sound. The Mk2 pumps them up nicely, not in an edgy, ersatz fashion but in a gentle reconstituting of the performance.

I had a break from working with the AirLens and Mk2 when I attended all three days of AXPONA 2024 and heard several high-performance systems. As there was more EDM music heard in rooms this year than classical music, I intuitively understood the torch has been passed. The old timers are fading and the new generation of HiFi enthusiast is showing up. I thought I would use some of the heavy LF tracks I snagged from the show in the review. It would be a good opportunity to casually compare these PS Audio components, and my Legacy Audio Whisper Speakers and Perlisten D212s Subwoofers to what I considered exemplary show systems.

The following are impressions of different systems in different rooms and at different times, so they are not to be taken as absolute comparisons. I had the opportunity to hear Ghost Rider’s “Make Us Stronger” on the Focal Grande Utopia EM Evo Speakers with the Naim NAC S1 Preamplifier and NAP S1 Statement Ultimate Mono Amplfiers. I also heard it on the Legacy Audio Valor Speaker System with Legacy’s i.V Ultra Amplifiers. The comparison was closer in time than usual for a show because the rooms were next to each other. The Focal/Naim combo seemed drier and less colorful than the Legacy setup. In addition, I felt the LF produced by the Legacy equipment was richer, fuller and with as much extension. I reviewed the Valor and i.V Ultra amps, so my preference is likely playing into the impressions.

What is telling regarding this review is that when I returned home, I sensed better resolution and sound stage depth from my Legacy Whisper DSW Clarity Edition Speakers and the Perlisten D212s Subwoofers with the Legacy i.V4 Ultra Amplifiers than either of those show systems. If I have the show components identified correctly, Naim used their own $35K streamer and Legacy used a Lumin streamer. My impression was that more was happening in my home rig with PS Audio, Legacy, Perlisten, and Iconoclast Cables than either of these systems at the show. Even though it was not a direct comparison, that’s a big plus for PS Audio. In the past when I heard top end systems at AXPONA and came home to the system with the sonicTransporter and SONORE Signature Rendu SE at the head, I never had the impression that my system was performing in the same range as the big rigs. Now, I do, and the PS Audio equipment is a big reason for it. The 20x DSD processing, I²S link, upgrading the HDMI cable to the Audioquest Fire Bird DBS, lifting the grounds, and experimentation with power cords maximized the AirLens and Mk2’s performance. These adjustments took the combo into territory that I had not expected.

Neutral and clean

I am currently working on a review of a nifty integrated amplifier, the Billie Amp made by a company named Heaven 11. The Billie Amp is as unique as its name, the merging of a DAC, class A tube preamplification, and class D output stage. It is named for the singer Billie Holliday, and it aims to bring grace and luster to digital listening. It is highly configurable, and while I am saving most of my comments on its operation for its own review, here I will state that in use with the AirLens, it has deeper tonal color and image saturation than the Mk2. Using descriptors that most audiophiles can appreciate, the Billie Amp has the character of a tube amp, whereas the Mk2 partnered with the Legacy Audio i.V4 Ultra Amplifier has the character of a fine solid-state amp. Both have outstanding refinement and the capacity to draw me in while listening.

My system building conundrum is twofold; some of the systems I build are complex and utilize both RCA and XLR outputs, in some instances splitting them to achieve up to 8 channels of amplification for grander multi-way speakers. The Billie Amp has only RCA inputs and outputs, whereas the Mk2 sports both RCA and XLR, which makes it the champ for those involved speaker systems. The diminutive AirLens is the master of both the MK2 and the Billie Amp. As I found several pleasing configurations with the Bricasti M5, so now I am finding several pleasing configurations with the AirLens and associated DACs.

I have traversed a fair bit of ground in my search for a new digital front end, and the equipment reviewed has altered my preferences. Rather than find the One, the hypothesized ideal digital source, I have been motivated to expand my horizons, to give sanctuary to multiple digital source components. I am surprised that the results of system building consistently showed that an affordable streamer partnered with the right DAC can outperform quite expensive integrated server/streamers. I have already determined to own the Bricasti M5 Network Player, as discussed in that review. Now, I am going to add to my collection the PS Audio AirLens. Together, they will be my streamer/server beachhead. With them I will pair various DACs to create a variety of systems having their characteristic sound. I intend on using the Mk2 as a reference DAC for reviewing with either the M5 or the AirLens at the head of the system.

Just as I have been using multiple streamer/renderers, I will be using multiple DACs. Because the Mk2 has a neutral tonal balance and sports both RCA and XLR outputs, it will be suitable for driving complex multi-channel speakers using three, or even four channels per speaker. I will seek another, simpler setup as an alternative DAC for single wired or bi-wired speakers not due to any deficiency in the Mk2 but to capture different combinations of attributes in music reproduction.

I enjoy variety in motorcycles and own both a 2013 Yamaha Star Stryker (cruiser) and 2016 Yamaha FJ-09 (sport adventure). These vehicles are fundamentally different in terms of design and handling, yet they are both motorcycles. Revisiting the digital front end and building many systems of different iterations has shown me that over the past five years, the variety of systems to be built is varied and I can experience a wider range of musical experiences if I select equipment not only based on perceived pedigree but on flexibility and configurability. Thus, I aim to have two sets of digital equipment with many optional configurations.

Currently, I am reviewing the Billie Amp by Heaven 11. It is an integrated DAC/tube preamp/class D Amplifier, and it has a characteristically warmer sound with deeper tonal color than the Mk2. It is designed to incorporate the cleanness of a class D amplifier and the second harmonic distortion of tubes. The systems built with each of them are as varied as if one was the Star Stryker (the Billie Amp) and the other were the FJ-09 (the DirectStream DAC Mk2). Within the context of using only a digital source, the variability of systems built these DACs is not unlike using both an analogue and digital sources. The performance spectrum of digital sources has grown wide such that the comparison is not far-fetched.

I share this with you partly to disavow the notion that I or any reviewer can tell you that purchase of a product will assure you obtain a perceived perfect result, that is, the best outcome. Only working through many iterations – and please, don’t waste your life waiting for break in, as it is useless – will progress your rig toward that goal. I also share this with you because the Mk2 is not the end all, be all DAC. Neither is the Billie Amp, but they are producing the best characteristic sounds achieved to date from DACs.

However, the additional features of the Mk2 allow for fundamentally different, and straight up, superior, audio systems to be built. I can’t use the Legacy Audio Whisper DSW Clarity Edition Speakers with the Billie Amp, nor the Aspen Acoustics Grand Aspen. These are my most formidable speakers and between the two DACs, only the MK2 accommodates them, which makes it the automatic winner versus simpler DACs.

Variety in listening experiences has always been very important to me. Even long-loved music is fresh, vital to me, when I can hear it with a new set of equipment. I opted to have two motorcycles of different genres that together are approximately half the cost of a big Harley Davidson. I am doing similar with my digital front end, as I have done with speakers. Rather than glom onto one speaker of one genre, I have what I consider superb examples of several genres of speakers. Now, I will distribute the funds I could use to purchase a very expensive all-in-one digital source to gain several excellent products to make a fleet of digital front ends for my systems. Thus far, in direct comparison to all-in-one streamer/servers, I am achieving comparatively better results across many systems. Have I built all possible systems with all these components? No, but the ones I have built and compared to expensive server/streamers have outperformed them.

Thus, my search for a new digital front end comes to a pause. Perhaps it is not the end, but I plan on spending a while with the following products: Bricasti M5; PS Audio AirLens; PS Audio DirectStream DAC Mk2; Heaven 11 Billie Amp. The Billie Amp is so unusually configurable and complimentarily different to the Mk2 that I am already announcing its presence before the review is published. Between these products I will have no less than one dozen digital front end iterations to accommodate any speaker I wish. As with motorcycles, I will be able to make highly captivating digital sources for streaming and file playback from a set of gear having a collective MSRP of approximately $12K. I will achieve both excellence and variety in performance at a price point that makes me giddy!

Wrap up

I am quite pleased by the experience of once again handling PS Audio products! I recall how precise the HCA-2 Amplifier sounded. Once again, I am struck by the precision of the AirLens and DirectStream DAC Mk2, with a nod to the Audioquest Fire Bird DBS HDMI Cable. PS Audio has a way of pushing the envelope on rendering a clean, neutral sound, one that can be partnered with a wide variety of speakers yielding outstanding results. In this review I have demonstrated that the Mk2’s performance is not dependent upon the AirLens but that it plays well with other streaming devices. I have also showed the AirLens to be a splendid streamer for use with both affordable and more extravagant DACs.

As my search for a new digital front end has developed, building systems has prompted me to expand my horizons with the goal that I will use more than one streamer, just as I already have more than one DAC. It seems the right time to shuffle DACS, to divest of some older ones and import some new ones. My plan is that the Mk2 will be one of the new DACS that will find a place in my home. Not only does the 20x DSD have appeal in how it rejuvenates older digital music but with both RCA and XLR high power outputs, it is ideal for driving multiple channels of amps, which I require to run the Legacy Audio Whisper Speakers (3-way) and the Aspen Acoustics Grand Aspen Speakers (4-way). I build some involved stereo systems and the Mk2 can drive them. Try that with some prissy NOS DAC!

The AirLens and DirectStream DAC Mk2 individually are excellent products, but together they are a formidable set. I built as many iterations of systems as I could over the past few months, and the AirLens and Mk2 consistently performed admirably. Especially for those who wish to build systems featuring multi-way speakers and who need the flexibility of both RCA and XLR connections, the Mk2 offers the option of eschewing a separate preamplifier and driving the amplifier(s) directly. I detect no performance penalty in doing so, and in fact you may gain much higher resolution, especially when employing the Ground Lift and Shell Lift features.

My final comment is reserved for the coupe de gras, the upgradability of the MK2! The software upgrades that will be visited upon the unit over time will assure ascending performance, a rarity in this industry. In essence, the DirecStream DAC Mk2 will not become obsolete, a powerful incentive which adds value to an already reasonably priced full-featured DAC!

Associated Components:

Digital Source: Bricasti M5 Network Player, Wireworld Starlight CAT-8 Ethernet Cable

Analog Sources: Realistic LAB 400 Turntable with Schiit Audio Mani Phono; Nakamichi CR-1A Cassette Deck

Streaming Music Service: Tidal; Qobuz

Interface: ROON; Audrivana

DAC:  COS Engineering D1 DAC Plus Pre-Amplifier; Eastern Electric Minimax DSD DAC Supreme with Burson, Dexa NewClassD or Sparkos Labs discrete opamps; Exogal Comet DAC and PLUS power supply

Preamp: Kinki Studio EX-M1+ Integrated Amp  (preamplifier mode)

Amps: Legacy Audio i.V4 Ultra; Kinki Studio EX-M1+ Integrated (amplifier mode); Exogal Ion PowerDAC (used exclusively with Comet DAC)

Integrated: Kinki Studio EX-M1+; Heaven 11 Billie Amp

Speakers: Legacy Audio DSW Clarity Edition; Kings Audio King III electrostatic speakers; Pure Audio Project Trio15 10” Coaxial version and Horn1 version; PureAudioProject Quintet15 10” Coaxial version and Horn version; Kings Audio King Tower omnidirectional; Aspen Acoustics Grand Aspen; Wharfedale Opus 2-M2 Monitors

Subwoofers: Perlisten D212s Subwoofers

IC’s: Iconoclast RCA and XLR Generation 2 with Ultra-Pure Ohno Continuous Cast Copper conductors; TEO Liquid Splash-Rs and Splash-Rc; TEO Liquid Standard MkII; Clarity Cable Organic RCA

Speaker Cables: TEO Cable Standard Speaker; Snake River Audio Signature Series Speaker Cables;

Digital Cables: Clarity Cable Organic Digital; Snake River Audio Boomslang

USB: Clarity Cable Supernatural 1m;

Power Cables: Clarity Cable Vortex; Snake River Audio Signature Series; Belden BAV Power Cord

Power Conditioning: Wireworld Matrix Power Cord Extender; Tice Audio Solo