PS Audio Stellar Strata Mk2 integrated amplifiers Review, Part 1 of 2

The PS Audio Stellar Strata Mk2 Integrated Amplifier is one of the most important components I have handled, but not for the reason you may think. In the process of reviewing this and one other integrated amplifier, I have reached what many would consider controversial conclusions regarding two channel audiophile system configurations, that is, the composition and arrangement of equipment. Those conclusions have potential to be material to manufacturers, and I do not wish to attach them to PS Audio. The component reviewed here, per se, is not the reason I have reached those conclusions, though it has been a part of the process of discovery.

I will be writing a separate Editorial regarding the controversial aspects of my system building. I wish for PS Audio to be disassociated with potential problems; I will own the potential fallout. Those conclusions are not about PS Audio, but the industry and my experiences building systems. I invite those who are curious to see that article. Here, I discuss an alternative system configuration and how the Stellar Strata Mk2 performed.

In the past, when I have pursued what might be considered controversial or debatable methods or conclusions using reviewed equipment, I have attempted to distance them from manufacturers. For instance, when I introduced the Landscape Orientation discussion, I separated it from my review of the Daedalus Ulysses Speaker to not cause unintended problems for the company. This review will follow that tradition. I encourage you to investigate the Stellar Strata Mk2 not only because it is a superb integrated amplifier, but for capabilities that you are not yet aware. Though my praise of use of two Strata Mk2 units seem effusive, the description of their performance is accurate.

It’s not every day that a reviewer writes about using a pair of integrated amps. You may have thought I have two systems and planned to use a PS Audio Stellar Strata Mk2 in each of them. I had no such intent. I am using both units in one system, my primary listening system, the one with the best equipment. Buckle up, this is going to get wild!

I am going to say several things that you will be strongly tempted to disbelieve. I will be sharing results that are so unexpected, so over-the-top, that it will sound like I am an advertising employee of PS Audio. I have no vested interests, nor have I received any perks from the company. I have available the same reviewer’s accommodation pricing that all reviewers receive, and I will tell you up front, as soon as this review is submitted, I will take advantage of it! For seventeen years, I have not been paid to write reviews, so I am not owned by anyone. I write what I discover and let the chips fall where they may. If you conclude that this review is dramatic, wait until you read my Editorial!

The odds are good that PS Audio may not buy into my conclusions in this review. So be it. I do not write to please manufacturers, but when the results deserve accolades, I give them. The company will agree that the Strata Mk2 is a nice piece of kit. But they will probably disagree that it is capable of performance exceeding systems that cost multiples more because they sell systems that cost multiples more. You read that correctly. In this review, I will share how I have successfully used two Strata Mk2 units to outperform every expensive combination of separates I have ever assembled in 17 years! Is that enough of an unexpected revelation to pique your curiosity?

Please do not dismiss my discussion out of hand. I will be discussing not only the Stellar Strata Mk2, but a principle of system development that I have explored over time, using two integrated amplifiers in either a mono or faux mono configuration! For four decades I have found pleasure in exploring equipment through a variety of setups to have a fresh experience often. That leads to some interesting systems and experiences. This article is about one of the most interesting. Perhaps you will agree, if you believe me.

Backstory

In 2007 I reviewed the Pathos Classic One Mk3, a traditional tube input and class A/B output integrated amplifier which is still in production, and that it has a MONO mode. After working with one unit, I was compelled to explore the mode and obtained a second unit, which turned out to be exciting. I loved the monoblocks configuration so much I bought them and cherished them for years. Eventually, as I escalated the separates in my system, they eclipsed the “Pathi”.  I let them go, but I never forgot the experience.

Recently, I spent time with the darling Heaven 11 Billie Amp Mk2 integrated amplifier. The Billie Mk2 is a combination of DAC, tube preamp stage, and class D output stage (or DAC/pre/D). Remember that combination, as it looms large in the results I am getting with the alternative system configuration. That little package of joy sounded so good, my mind drifted back to the Classic One Mk3, and a wild thought took possession of my mind, “What if I got another one of these and ran them mono, like the Pathi?” Had 17 years of technological development raised the bar for such a system? You are reading about the outcome of a parallel system comprising two PS Audio Stellar Strata Mk2 Integrated Amplifiers!

As a system builder, I was curious whether the results achieved with two of the Billie Mk2 was an anomaly, or had I found something overlooked in system configuration? The DAC/pre/D combo seemed unusually important. I consider class D amplification to have come of age; about two years ago, I made the decision to stop reviewing class A, A/B, and tube amplifiers in favor of only class D. I wondered if joining these three functions had created a new breed of component that could be leveraged to perform as an outlier.

I approached PS Audio’s Paul McGowan with an unusual request, that I be sent two units for review! This is not the kind of plan that a maker of audio gear usually supports, sending another unit purely for exploratory purposes. I am usually on my own, which makes Paul McGowan and PS Audio rare. In terms of the performance capabilities of the Strata Mk2, it was a good move on his part. I suspect neither the company, nor the community had any idea what this integrated amp – actually, two of them – can do!

Where designers and theorists fear to tread

I use only a digital source, a streamer/file server, so how would I use two stereo integrated amps? Simple, I split the digital coaxial (SPDIF) signal emanating from my streamer (I have two streamers, both reviewed here at Dagogo.com, the PS Audio AirLens and the Bricasti M5 Network Player) using a single ended (RCA) Audio Sensibility silver OFC Y-cable and sent the resultant digital outputs to the appropriate integrated amplifier. Readers’ rolling their eyeballs, industry members howling with mockery, because we all know that doing such compromises the digital signal, absolutely wrecks the sound, right? Oh, you’ve done it? You have tried splitting it and sending to two integrated amps? Or are you self-assured about your opinion? If you haven’t done so and are mocking, then you are arrogant for thinking you know how it sounds when you haven’t tried it. Please do not be mad at me; I’m being truthful.

The unorthodox system configuration is to use stereo integrated amplifiers in what I like referring to as a faux mono configuration. Unlike the Pathi’s class A/B output which could be summed to mono, both the Billie Amp Mk2 and the PS Audio Stellar Strata Mk2 have class D amplifiers, meaning the two channels cannot be summed. Initially, I thought that precluded use with single wired speakers, but perhaps I could employ only one channel to drive single wired speakers. I have not tried it, but certainly will eventually. But before I do, I will ask about any potential strain/stress to the integrated amp if using only one channel. Better to ask than find out the hard way!

That brings up a point about alternative configurations. Most manufacturers don’t support such configurations, and the assumption is that the audiophile is on their own, meaning no warranty support. It is possible that PS Audio will not support the system configurations I discuss here and warn the user that it would void the warranty. I believe that what I have done in system configurations presents no harm to PS Audio equipment and would hope that the company supports the alternative configuration rather than condemn it. But I will say up front, the results are so good that I will continue to use it regardless of the company’s decision.

Unscrupulous hobbyists will try certain things, wreck a piece of kit, then claim to the manufacturer that the unit failed them. Often, the manufacturer can tell that the claimed cause of failure was illegitimate, but often they don’t challenge it publicly for fear of a nasty exchange and negative publicity to their business. I have exhorted audiophiles to own their experiments, that is, have integrity with the outcome of exploratory system development. In some of the alternative systems I have built there has been some risk of damage to equipment from mistakes made in assembling them. I rolled discrete opamps, and if they are inserted into the wrong position, it can fry a DAC. Here, especially regarding the I²S signal, I had no idea what could happen when the digital signal was split. I bought the second unit of the Billie Mk2 with my own money partly because it would be manipulative to experiment with a company’s product clandestinely. If I bought a second unit and it was wrecked, I would assume the penalty, not Heaven 11.

When it came to the Stellar Strata Mk2, I was up front with PS Audio about my intent to pair the integrated amps. I had more confidence following the Heaven 11 experiment that there would not be damage to the units. The goal was to have integrity in my dealings and buffer companies from possible bad outcomes. When the audiophile tries alternative configurations that are unknown, they are responsible for the outcome, not the company! You need to own your experiments. If you want the glory of discovering a new combination, then you need to own the potential for cost and loss. If you want to shunt your failures onto the company, then you are acting dishonestly, and you likely have wider personal problems associated with your love of money.

I occasionally discuss alternative configurations with equipment manufacturers to check on operational suitability. I do not expect them to agree with the application or see the benefit in it. Many prejudge the alternative configuration due to theory. If at the end of this article, you are prepared to try my method, prepare also to be potentially mocked by some industry members and hobbyists. Some people are tied to conventional methods and either cannot or will not step outside the box. They are convinced they have the best method and will not tolerate disagreement. So be it. Disagreements do not need to destroy relationships. Laugh with them and move on!

Again, do not join two channels of class D amps. To date I have used speakers that are bi-wired or even tri-wired or quad-wired. I own speakers which can accommodate tri-wiring (Legacy Audio Whisper DSW Clarity Edition) and quad-wiring (Aspen Acoustics Grand Aspen). With speakers capable of tri-wiring or quad-wiring, I double up speaker cables on the amp’s output potsts, using one set of cables with spade terminations and one set with banana terminations. It’s a perfect solution to accommodate more prodigious speakers! Care must be taken whenever setting up a system. Do not set up a system when you are tired. Do not be hasty! I always triple check connections, even when confident. I strongly suggest you adopt that cautionary practice. There have been a couple instances when I realized I had mis-wired a connection the third time I checked it!

Having mentioned the Billie Amp Mk2 here, the first question readers would have is, how do they compare individually, and is the Strata Mk2 worth almost double the money? Generally, the Billie Mk2 is more romantic, but not sloppy. It has less fine edge on instruments and images are not as sharply defined, i.e., cymbals, guitar strings, as the Strata Mk2. They both are capable of rich, gorgeous tone, but much of it depends on the ancillary equipment. Tonally, I prefer the Bricasti M5 Network Player with the Billie Amp MK2, but I prefer the AirLens with the Strata Mk2. At this time, my favorite configuration is the AirLens with the Strata Mk2. I am astonished at the generosity of the performance! More on that in a bit.

I had used the AirLens with the DirectStream DAC Mk2, and that combo did not have as supple and tonally rich sound as the AirLens with the dual Strata Mk2. That was only one of the big surprises in store for me during this review – and they were nearly all good surprises. My creativity spurred by positive results, I thought of the possibility of pairing of the DAC/tube pre/D Billie Amp Mk2 with the robust solid-state DAC/pre/D of the Strata Mk2! My first configuration would place the Strata Mk2 on the bass and the Billie Mk2 on the mid/treble. Then, I would switch them! Within minutes I came up with a dozen discrete configurations and setups between such a pairing, starting with which integrated would handle the bass and which would handle the mid/treble. No one knows the best result; the system would have to be built. That’s why I love being a system builder! It’s a continuous process of discovery and beautiful new experiences! As the systems become more compelling, I am more emotionally moved, sometimes to tears. I used to think that crying while listening was nonsense, but now with age and appreciation of the beauty of the performance and the exquisite reproduction of it, at times I cry. Boring systems do not make me cry, but I do not judge systems by their emotional effect.