It feels like a milestone that I have been writing for Audiophilia long enough to review the second generation of a product I covered after its launch. Here we are with the PS Audio Stellar Strata Mk2 (USD 3499), the recently updated integrated amplifier in PS Audio’s middle-range Stellar series of electronics.

An established player in the high end audio scene, PS Audio is about five years into an era of using a direct sales business model and they seem to be stronger for it. Design, engineering, manufacturing, shipping and service all are handled at their headquarters in beautiful Boulder, Colorado. While I can't speak to the performance of the business, the market presence and brand identity of PS Audio has grown and matured in the last few years.

Looking back on my review of the original Stellar Strata, I enjoyed my time with it and loved the sound, although I thought its streaming app was a bit basic and would have liked to see Bluetooth included for convenience. Interestingly, I did not mind the lack of an internal phono stage. After reviewing a handful of integrated amps with killer phono sections (Parasound, Musical Fidelity, Aurorasound), my preference for separate components has faded. These days, I like to use separates for the components most likely to become outdated first, namely digital sources like streamers.

With that personal context in mind, naturally, when I saw the announcement that the new Stellar Strata included a phono stage (historically, a strength for PS Audio) instead of a streamer, I was compelled to hear it. Thanks are due to Frank Doris, PR liaison for PS Audio, who facilitated this review. How has the Stellar Strata matured as it has grown up? Let’s discuss how it fared with a suite of complementary components and speakers in my system.

Features & Specifications

The Stellar Strata Mk2 is a full-featured integrated amplifier, but unlike its predecessor not quite an all-in-one because it doesn't contain a streamer source. On the surface, the most substantial change is the inclusion of a phono stage. Under the hood, most circuits have been updated as well, including the latest version of PS Audio’s Digital Lens DAC, a tweaked Class D power amplifier section. The preamplifier section has been completely redone and features a class A preamplifier circuit with an all-analog volume attenuator. The class A headphone amplifier is carried over from the original Stellar Strata.

Design & Build

The proven Stellar design language continues with the Stellar Strata Mk2. It is clean and elegant to observe but substantial and luxe to the touch. The same heavy gauge textured aluminum used for the clam shell chassis is also used on the volume knob. This material looks sleek in black, as on my review unit, and is impervious to fingerprints.

Although the Stellar uses IcePower-based Class D output modules, it has the heft of a Class A/B amplifier.

As with the first generation, in terms of user interface, the Stellar Strata Mk2 has a nice feature-to-button ratio; its single button belies the suite of configurability options in the menu.

The compact, elegant and intuitive plastic remote is also carried over. It wasn’t broken, and they didn't need to fix it.

All told, the design is distinctly PS Audio, elegant and sure to age well.

A minor note, but something I notice as a reviewer is the IEC power cable included with amplifiers. Not all generic black cables are the same! Many high-end amps in the same price bracket as the Stellar Strata Mk2 ship with wimpy 18-gauge power cables. PS Audio gets a gold sticker for spending a few extra nickels for a heavier 14-gauge cable.

Review System

Digital Sources: Wiim Mini Streamer, TEAC VRDS-701 CD Player/DAC (review forthcoming)

Analog: Cambridge Alva TT V2 Turntable, Cambridge Alva MC Cartridge

Amplification: Cambridge Audio EVO 150, Parasound HCA-750A

Speakers: PSB Synchrony B600, Care Orchestra Celestial Deep Breath Evo, Audio Physic Step, Audiovector QR1 SE (review forthcoming)

Cables: Audio Art Classic Series

Listening

Setup of the Stellar Strata Mk2 is straightforward, taking just minutes to position the unit and connect power, sources and speakers. There are ample optional settings to configure, like digital filters. One setting is especially noteworthy: Analog input #2 is set to bypass the volume control by default. This caught me quite by surprise because I did not read the manual! Don’t connect full signal sources to this input without changing the volume bypass.

Before getting into the music, I made a point a putting my ear to a speaker with the volume at zero. The minuscule hum present with the original Stellar Strata is completely silent with the Mk2. While this wouldn’t impact daily music listening, I appreciated this positive side effect of all the tweaking PS Audio did to the internals.

For digital listening, I primarily used the optical and coaxial SPDIF digital inputs. The USB and I2S (the darling protocol of the moment) were not used. The heavyweight TEAC VRDS-701 provided a serious comparison for the DAC in Stellar Strata Mk2. Both the TEAC and PS Audio flattered the optical output of my Wiim Mini streamer, making it sound nearly impossible that I was using a $89 source.

I have most Pink Floyd albums on CD, but don’t spin them too much because they often feel too familiar. Lately, I’ve been exposing my kids to some classic albums, and it was time to pull out The Dark Side of the Moon (Pink Floyd Music Ltd, 2011 Remaster). With DSOTM in rotation, I worked in some deep listening sessions for this review. Utilizing the coaxial input of the Strata, I was enamoured by the quality of the small details contained in this impeccable album. Spatial cues, timbral realism and telepathic speed were all on point. Switching to the TEAC (more details in the forthcoming review), I can say it brought a slightly more authoritative sound without dunking on the Stellar Strata Mk2. This was just one relatable example of my delight with the digital capabilities of the Stellar Strata Mk2. For digital sources, generally, I expect the DAC in the Strata Mk2 should do justice to all but the highest-end transports.

In an integrated amplifier my main criteria for a phono stage is to be as quiet as possible and let the cartridge and turntable do the work. The phono stage in the Strata Mk2 is an admirable performer - shockingly quiet, and not just quiet for a built-in unit.

Heavy in the vinyl rotation during this review was the Hyperion reissue of Feather on the Breath of God, by Gothic Voices & Emma Kirkby, a landmark 1982 recording of works by medieval Abbess Hildegard von Bingen. Technically, Hildegard von Bingen’s music is monophonic chant with little to no accompaniment, but this categorization completely undersells how intoxicating a listen it can be.

I’ve been into Hildegard von Bingen since my high school Latin days. Feather on the Breath of God was the watershed recording in a revival of her music with many excellent subsequent recordings by various ensembles like Anonymous 4 and Sequentia. These recordings vary widely in terms of their spatial qualities, from blissed out reverberance to overly closed in.

Feather on the Breath of God is a great demo record for the vocals alone, but its sense of space is perfectly balanced between cavernous and stuffy.

It’s hard for Feather on the Breath of God to sound bad, but utilizing the phono stage in the Alva TT added enough of a veil that the perfect air captured when using Strata Mk2 was gone. The Strata bested my Parasound ZPhono, too. It was close in terms of noise floor, but the synergy wasn’t enough to bring the level of vibrancy apparent with the Strata’s phono stage.

Hardcore vinyl enthusiasts with high-end or exotic MC cartridges might be still attracted to separate phono stages for flexibility and specific features but those using MM and entry-level MC cartridges should be more than satisfied with the Stellar Strata Mk2.

The headphone amplifier in the Strata Mk2 translated the skills of the various preamp sections into my private listening beautifully. The Class A amplification is plenty powerful, easily driving my 300 ohm Sennheiser x Massdrop HD6XX headphones. The Strata Mk2 had better synergy with headphones with a more open presentation than the intimate midrange-centric HD6XX. The Sendy Peacock planar magnetic headphones were a brilliant match. I heard control, wide and deep staging and distinct imaging on any genre. Even though it is not brand new, PS Audio is not skimping on this headphone circuit, and with thoughtful matching, it could render external headphone amplifiers unnecessary for all but the serious head-fi enthusiasts.

The front end of the Strata Mk2 is excellent, but what about when the rubber meets the road? How does the Stellar Strata Mk2 deliver the power? For a torture test, I streamed a favourite early 2000’s trance set from DJ Tiesto, In Search of Sunrise 3: Panama (Songbird, 2002). The PSB B600, Audio Physic Step, and Audiovector QR1 SE speakers are all reasonably demanding and deserve some high-quality power. But none were even close to a tough match for the Stellar Strata Mk2. The Care Orchestra monitors, though, absolutely chug amps, and need serious power to deliver perfectly tight bass. The PS Audio helped them sound the best I’ve heard. It would be tough to find harder-to-drive price price-appropriate speakers for the Stellar, suggesting speaker matching is likely a matter of taste rather than compatibility.

Relative to my long term reference integrated, the Cambridge EVO 150, the Strata Mk2 will appeal more to the hardened audiophile crowd who are likely to prefer a separate streamer and appreciate a high quality MC input. Power specs are similar but for hard to drive speakers the PS Audio is the easy choice here. For a streamlined lifestyle system the Cambridge could win on slick software and HDMI eARC input.

The similarly priced and featured Parasound HINT 6 is the heavyweight incumbent in the arena. I don’t like to rely on my sonic memory, but I just don't remember that much excitement from the Parasound despite extremely authoritative power delivery. I can say PS Audio has Parasound beat on industrial design, if their build quality is equal. Parasound wins on analog configurability (with bass management and MC loading options) while the PS Audio wins on digital flexibility.

Building a system around the Stellar Strata Mk2 would be extremely straightforward. It is not an amplifier to buy and subsequently upgrade one section at a time. Rather decide on speakers than buy and hold.

The sound of the Strata Mk2 strikes a balance between neutrality and insight, full body and fine detail. Nothing seems out of balance, and individually, all areas of the frequency response are handled with authority and excitement. PS Audio calls the Strata Mk2 “tube-like” and “lush.” I am not sure about the former claim, but I emphatically agree with the latter.

Conclusion

The first-generation Stellar Strata was a fine-sounding and genuinely recommendable product, but its identity kept it straddling two different camps in the integrated amplifier market. On the one hand, PS Audio’s emphasis on engineering and performance gave it plenty of audiophile credibility where it competed with the likes of Parasound, as I mentioned. Inclusion of the streamer and billing as an “all-in-one” solution pitted it against the slick Cambridge EVO and Naim Uniti Atom in the lifestyle side of the scene.

The Stellar Strata Mk2 (USD 3499) retains its made-in-USA goodness, adds a few performance tweaks, and, critically, with the swap of a streamer for a phono stage, solidifies its identity in the audiophile realm. I did not find a single aspect of the product that was not impeccably well executed. The result is a well-executed integrated amplifier to serve as the centrepiece of a system for the long haul. It’s extremely competitive and an excellent value. PS Audio has found a groove with this new Stellar Strata Mk2, and it is a must-hear in its class.

Further information: PS Audio