Due to the manufacturer’s lineup and lineup change, Stellar Strata is currently the only integrated amplifier in the PS Audio catalog. During my acquaintance with this apparatus, I was constantly visited by the thought: the “source” in this apparatus is no less than the “amplifier”. So it turned out to be a very self-sufficient symbiosis.
There are many unusual things here. It would seem, how can an amplifier with a DAC on board surprise you now? Almost all produce such universal all-in-one models, 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 unusual.
The back panel is 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. From the auxiliary switching there are control trigger connectors and a service USB 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 “upper 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 output stages of the DAC, 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 sorts of combinations of class A with class D is 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 like 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 collected neatly.
The next important component for such modern digital-to-analog devices is software and compatibility. And here 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 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, at startup 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 didn’t manage to write 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 settings menu itself, 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 complete it, we did not agree. How do we bet? We go to the PS Audio website, rack our brains, look for where it should be located, 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 is generally 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 that in the case of Stellar Strata, in the long term, 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.
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 is cozy, friendly and even sweet, but without cloying. There seems to be a lot of everything, but in moderation.
This is not a reference neutral sound. But that was exactly what was intended! And if you do not 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.