Due to the change in the model range and lines of the manufacturer, at the moment the Stellar Strata is the only integrated amplifier in the PS Audio catalog. During my acquaintance with this device, I was constantly visited by the thought: the “source” in this device is no less than the “amplifier”. So it turned out to be a very self-sufficient symbiosis.
There are a lot of unusual things here. It would seem, well, what can surprise an amplifier with a DAC on board now? Almost everyone produces such universal models “all in one”, but in our case everything is somewhat different.
Nice looks – totally predictable for the Strata line. Rounded on the horizontal edges of the front panel, the on/off button in the form of a blue logo (like PS Audio network splitters), a miniature display and a rotating volume control knob. Plus a headphone jack. At first glance, nothing out of the ordinary.
The rear panel is already more interesting. One third of it is occupied by digital inputs, the other – by analog inputs (including balanced and unbalanced preamplifier output), and another third – by terminals for connecting acoustics. By the way, the terminals are very nice, massive and of high quality.
Of course, the digital part is more interesting. There is a connector for connecting to a network via twisted pair (and the device also has Wi-Fi), a USB audio input, an optical input, a pair of coaxial inputs, and most importantly – an I2S input that looks like an HDMI connector. In general, this is a rare type of connection, but PS Audio uses it extensively.
In this case, the DAC can work via I2S in tandem with its own transport, which, in turn, works with both CD and SACD disks. Auxiliary switching includes control trigger connectors and a USB service port.
The DAC is built on the ESS Saber Hyperstream and can work with both PCM and DSD. The input signal is not recalculated and is processed by a CPLD chip (a simplified analog of FPGA) as part of a proprietary circuit called Digital Lens, the main task of which is to reduce jitter.
The I2S input is capable of accepting PCM up to 384 kHz, as well as DSD64 and 128. Coaxial inputs accept PCM up to 192 kHz, optics up to 96 kHz, and USB accepts PCM up to 384 kHz, and DSD64 and 128 in DoP mode.
When using the built-in streaming module, the “top bar” will be 24/96, and of the services Tidal, Qobuz, Spotify, Napster, iHeart Radio and DLNA are supported on the local network. You can also pay attention to the DAC output stages operating in class A, as well as the fact that passive filtering is used.
There is a preamplifier in the signal path between the DAC and the power amplifier – and it is quite unusual. Fully balanced circuitry, assembled without capacitors in the circuit and operating in Class A. Overall, this is the manufacturer’s long-used “Gain Cell” circuit with variable gain.
Next is the power amplifier. The manufacturer describes the circuit not just as class D, but as something hybrid called “AnalogCell” and has a decent enough declared power of 200 watts into 4 ohms per channel. If you look at the boards, it becomes obvious where the PS Audio’s own boards are of a characteristic purple color, and where the ICEpower 200AS2 output amplifier is – the marking is visible, no one is hiding anything.
So “AnalogCell” should be referred to as a pre-amplifier, but it is assembled separately and on a PS Audio board. You can see that all kinds of combinations of class A with class D are an option found by many manufacturers, but the implementation and sound are different for everyone.
It is also necessary to mention the manufacturer’s statement that, despite the circuitry, the device is made in such a way that the sound is more similar in character to a tube sound. In addition to the power amplifier for working with acoustics, there is also a separate, class A headphone amplifier on board – with an output power of 300 mW into 300 ohms and 3.25 watts into 16 ohms.
The body itself accounts for a very significant part of the total weight of 9.5 kg. There are no toroidal transformers or impressive heatsinks here – at first glance, the filling looks more like a digital source or a preamplifier. However, from a practical point of view, everything is assembled neatly.
The next important component for such modern digital-to-analog devices is software and compatibility. And here PS Audio Stellar Strata has mixed results.
The company has several devices (DirectStream DAC, DirectStream Junior, PerfectWave DAC) that are Roon tested and Roon ready. But Strata does not have this status yet – and I was not surprised when the current version of Roon did not recognize the device on the network.
Rumor has it that control is possible using JRiver, Bit Perfect, Amarra and Pure Music, but these capabilities need to be dealt with separately, but I would like, of course, Roon compatibility – especially considering that the manufacturer already has positive experience.
The device’s own network capabilities are a streaming module and a native application. First, you need to make Stellar Strata friends with the network – there are not many difficulties here, but there are some peculiarities. For example, with the initial settings, the tablet connects to the device as a Wi-Fi hotspot, and only then the application sees the device on the local network. But tuning in with such a connection is not at all easy.
If you take a wired connection, no problem. But connecting the Stellar Strata to a wireless network is a little trickier. I did not succeed in registering the parameters from the application on the tablet. I had to do this from the menu on the front panel of the device – using buttons and a volume knob, which in this case turns into a navigation knob.
Imagine how to enter a complex password for Wi-Fi with such manipulations? But this is how it works. However, this is not a feature that needs to be accessed on a daily basis.
The device’s settings menu, displayed on the front panel, is not very convenient. Not visual, not intuitive, and at first you need to check the instructions in order to understand the logic of movements. Of course, you need to go through all this only once after the device has settled in the house, but the anticipation “I’ll turn it on and listen right away” will not come true. However, this will be the case only if connected via a network – the rest of the switching or working in the USB-DAC mode did not cause any complaints.
An application for iOS devices is also a quest. It exists, but it is not in the AppStore. We did not work, we did not agree. How do we bet? We go to the PS Audio website, rack our brains, look for where it should be, find it, read the QR code, and now the application is loaded. True, iOS does not allow it to run. You need to go to the security settings, make permission on this account – and then the application will become active.
It also works specifically. Inside there is a set of settings, mostly unusual – for example, a programmable alarm clock. But the interface as a whole is simple, and I limited myself to using the streaming application only for Internet radio.
Coupled with the fact that the upper streaming bar is 24/96, using the device in USB-DAC mode paired with some third-party software is much preferable. Especially if you need to combine streaming and local file library with one application.
And the streaming component … I would say so – now it is rather not there than it is. But let’s remember that PS Audio is a company that entered the streaming device market a long time ago, and there are some very remarkable and well-deserved devices in its past and present.
I think, in the case of Stellar Strata, in the future, everything will be decided by firmware and software updates. And of course, I’d love to see compatibility with Roon. In the meantime, we will consider the device as an integrated amplifier with a DAC on board – and, to some extent, with a streamer.
The main test was carried out in the variant of using an amplifier and a built-in DAC with a USB connection, but you shouldn’t forget about the possibility of connecting a usual disk transport either. And I2S switching – if, of course, you have something to connect in this way. But nevertheless, I wanted to focus on using it in tandem with a computer – especially since I have all the software there, and an extensive music library on the server, and streaming services.
To begin with, I put on a recording of “The Best of the Dial Years” by Charlie Parker and Miles Davis. The character of the sound is detailed, with a noticeably pronounced effect of attractiveness, a kind of immersion in sound. The old record sounds rather bright and, indeed, with some vintage tube character.
The intelligibility is not bad – and it seems that it is emphasized on purpose, due to which the sound is perceived as interesting and multi-part. The presentation is expressive – both in the middle and at the top. There is no point in judging low frequencies from this recording, so we will pay attention to them later.
With a perceived brightness, the sound is not sharp, but even softened – bright, but warm. Monophonic sounding also turned out to be unusual – not so much the elaboration in depth is noticeable (although it is present), but a very wide panorama. It’s not stereo, of course, but the width of the sound is impressive.
The next disc is Colin Vallon Trio “Rruga”. There is good rhythm and elasticity, the detail is felt higher than it really is. The presentation is not exactly holographic, but some of the claims are obvious. At the same time, all this is unusually mixed with a share of warmth and softness. The result is a slightly psychedelic atmosphere filled with juicy but muted colors.
The velvet-airy wide stage also contributes to this perception. The mid-high range seems slightly emphasized, on the other hand, and the volumetric bass turns out to be proportionate. It seems that the entire sound as a whole, across the entire range, is somewhat emphasized and more textured than usual.
In general, everything turns out emotionally, but the nature of emotions rather goes a little into noir, into a light psychedelic, completely devoid of bravura or deliberate joy. It is clear that the device has an unusual character and its own interpretation of sound. And already at this stage, it can be noted that the sound can be characterized in very different ways, but certainly not as boring or pedantic.
Then he staged the much-loved album by Diana Krall “When I Look In Your Eyes”. And I must say, listening for 20 minutes did not send me into a sound sleep. The sound is cheerful, with a savor of after-sounds, it seems less monotonous than usual. Emotions are perceived brighter, but no puppy joy is observed. The warmth is there, but it is unobtrusive, the vocals are well developed and not exaggerated relative to the rest of the sound.
The piano parts have a slight touch of synthetics, or rather, a light ringing color with an emphasis on semitones, but no more. And, in principle, there is much less synthetics in the sound than I expected. Instead, there is a warmth, similar to a vintage lamp, moderate softening and some kind of obvious “fluffiness” of the sound and volume, which is drawn by this sound. Plus a good rhythm – confident, but not arrogant.
On the Eddie Higgins Quartet Featuring Scott Hamilton’s “Smoke Gets In Your Eyes”, you can hear the familiar presentation of the apparatus itself, but the style of performance and recording of Venus Records is perfectly recognizable. In general, the amount is obtained without bias in one direction or another – everything turned out harmoniously.
First of all, I liked the rhythm. He is always emphasized, but at the same time soft and delicate when needed – or quick and whip, if needed otherwise. The dynamics are not just good – they are emotional.
The bass is very good in terms of content – and it is not formally simplistic. The detail is still the same, slightly accentuated by the overtones and textures, which very well masks the fact that the most subtle shades and nuances are formalized and simplified. One kind of replaces the other, and in general the sound does not seem rustic or dull. And I didn’t expect full-fledged detail – the one I’m used to – but in practice this detail is much more expensive.
The presence of warmth in the sound is not annoying, although I don’t like warmth. It’s just that here it is of such a quality that it is in moderation – not a lot and not a little. The wholeness of the picture does not fall apart – everything is in its place and in well-combined proportions.
Dimmu Borgir’s album “Puritanical Euphoric Misanthropia” showed that the tract coped with dynamics even with such material. But where there is a synthesizer sound on the recording, it is very noticeable, and the sound becomes a little comical, toy.
And the rest – quickly, energetically, fervently, with a good scene and good detail. And very emotional, but a little more joyful than the average could be. And here it is already difficult to say how much this is combined with specific music. But according to formal criteria, it is better than expected.
Finally – Bach’s Brandenburg Concertos. The difference between the highrez and the 16/44 is played out quite clearly, the sound has a good resolution and decent dynamics.
In terms of detail, you can find a number of minor simplifications, there is a bit of synthetics in timbre, but this is hardly noticeable, because the general handwriting masks all this very well, and the artificial “lamp-like” clearly levels the presentation in such a way that everything as a whole is perceived quite naturally. Albeit with an obvious degree of coloration. The scene turns out to be large-scale, airy, with quite brightly and clearly outlined images, without lethargy or weakness.
I would also like to say a few words about the headphone amplifier. I really liked the way it works. The sound is neutral, detailed and dynamic, with the slightest touch of synthetics, which, however, you cease to notice after a few minutes of listening.
Perhaps this is one of the very good options for devices operating in class D. The main thing is that synthetics are almost invisible, and the color really looks like a lamp. Even if there is warmth and softening in it, the sound turns out to be cozy, friendly and even cute, but without cloying. There seems to be a lot of everything, but in moderation.
This is not a reference neutral sound. But this is exactly what he intended! And if you don’t try to stick to these criteria, then you get a very versatile device with a full-fledged digital source on board, as well as with its own brightly individual character of sound, which is not similar to other equipment.
Official site: www.psaudio.com
|Unit Weight||13.5 lbs [6.1 kg]|
|Unit Dimensions||17” x 12” x 3”|
|Shipping Weight||17 lbs [7.7 kg]|
|Shipping Dimensions||23”x 18” x 9”|
|Input Power||Model specific 100VAC, 120VAC, or 230VAC 50 or 60Hz|
|Maximum Power Consumption||500W|
|Mains Power Input||IEC C14|
|Fuses||100V T250V-2.0AH (5A Slow Blow)|
120V T250V-1.6AH (4.5A Slow Blow)
230V T250V-1.0AH (2.5A Slow Blow)
|Accessories included||US (NEMA 5-15P) (all versions)|
Schuko (CEE7/7) (230V version)
UK (BS1363) (230V version)
|RCA||3 stereo pair|
|XLR||1 stereo pair|
|Digital audio inputs|
|I2S||1 PCM (384KHz max)|
Compatible with DirectStream Transport SACD handshake for DSD playback
|Coax||2 PCM (192KHz max)|
|Optical||1 PCM (96KHz max)|
|USB||PCM (384KHz max)|
DSD64 (DoP) DSD128 (DoP)
|Analog Audio Outputs|
|RCA||(Analog Unbalanced) 1 stereo pair|
|Headphones||One 1/4″ headphone connector front panel|
|Maximum output||20 Vrms|
|Input Impedance||47KΩ single ended RCA|
100KΩ Balanced XLR
|Output Impedance||100Ω single ended RCA|
200Ω balanced XLR
|Frequency Response||20Hz – 20KHz +0/- 0.25dB|
10Hz – 100KHz +0.1/-3.0dB
|S/N Ratio||1KHz >110dB (max output)|
|Channel separation||1KHz >90dB|
|Input separation||1KHz >90dB|
|THD&IM||1KHz < 0.025%|
20-20KHz < 0.05%
|Output power @1% THD||300Ω 300mW|
|S/N Ratio 1kHz|
|>95dB (max output)|
|THD & IM 1Vrms out||300Ω <0.05%|
|Output impedance||<4 Ω|
|THD & IM||< 0.02% @ 1KHz, 1W/4Ω|
< 0.02% @ 10-20KHz, 1W/4Ω
< 0.05% (90kHz BW) @ 10-50 KHz, 1W/4Ω
< 0.01% @ 1KHz, 37.5W/4Ω
|Output Power||Both channels driven 120vac mains, 1kHz, 1% THD|
100W minimum @ 8Ω
200W minimum @ 4Ω
Stable for musical transients @ 2Ω
|Volume Control||0-100 (1/2 and 1dB steps, 80dB total range)|
|Balance Control||24dB each direction in 1/2dB steps|
|Home Theater Mode||Assignable to any analog input|
Adjustable (in setup) to any level
|Polarity (phase) Control||Digital sources only|
|Filter Control||3 selectable digital filters (PCM digital sources only)|
|Trigger output||(3.5mm 5-15VDC) 2|