Xact S1 Evo server/streamer
Every now and then a component comes along that rearranges expectations to such an extent that its necessary to recalibrate the potential of that particular product category. The Xact S1 Evo has done just that for server/streamers, I now know that there is more, quite a lot more that can be achieved with a file streaming source than I had previously experienced and it’s not making reviewing life any easier.
Marcin Ostapowicz has been obsessed with file streaming for many years, he started off making software for Windows which was released as JCat in 2009 and this became JPlay shortly thereafter, subsequently he built soundcards but as a Mac user I was never able to appreciate these developments. In 2022 JPlay the iOS control app was launched and a year or so ago I got to try it, JPlay has been my control software of choice ever since. It simply outperforms everything else I have tried on a wide variety of network streamers. Control apps shouldn’t make a difference but that difference is not hard to hear. Today the JCat name is used on soundcards, cables, power supplies and all manner of streaming ancillaries.
The Xact S1 was launched in 2023 with JPlay as its natural partner and now the Xact S1 Evo sits at the top of the company’s digital source tree. It’s an unusual looking beast with little of the elaborately machined aluminium found in competing streamer/servers and I suspect that this helps, albeit not as much as what goes on inside. Another external element worth mentioning is the choice of feet, these are Immotus CL isolation feet made in-house and available separately, there are three of these aluminium and ceramic feet under the case. It’s worth mentioning that you get a lifetime license for JPlay with the Xact S1 Evo and it’s hard to imagine this streamer sounding better with anything else.
On the back of the box is a row of RJ45 ethernet ports which give the impression that the Xact S1 Evo provides network switching capabilities on top of its primary functions, but that is a little misleading. You can use it as a switch but not if you want to use it as a server or streamer, it’s an either/or situation which seems a little odd. In practise the only socket required is the one marked LAN 1 which you hook up to the router.
The other key connection is the SD card slot, this is where the operating system resides on a card that Marcin has selected for the purpose. It’s a single cell type (SLC) where only one bit of data is stored per cell, which gives it very fast read/write speeds and a considerably greater lifespan than alternative types. The reason for putting the OS on a removable card is that it allows updates to be performed on a PC rather than in the machine, which while it requires a bit more interaction on the users part does mean that the internal processor isn’t having to be constantly looking for updates online, which lightens its load and reduces electronic noise. It was necessary to perform one update whilst the Xact S1 Evo was with me and I did this with a card reader I had for the camera, some PCs have these built in but they are inexpensive devices if you don’t have one.
A more fundamental reason for the Xact S1 Evo’s prowess is the custom motherboard that runs this highly specialised piece of electronics, this was developed specifically for audio purposes rather than being a modified motherboard built for general computing. Marcin has selected components for minimum noise and installed a “significantly upgraded” OCXO clock for maximum precision and stability, it’s a not stone unturned, cost no object lesson in how to build processing for a streamer and explains both the price and the sound quality on offer. I did ask why there isn’t a clock link on the unit and was told that it would be very difficult to find a better clock than the one on the board.
The final link is a Phantom music drive cable which connects a 4TB solid state drive (8TB is an option), the server specialists at Pachanko Labs also pay a lot of attention to this link so there is undoubtedly something in it. Naturally the whole machine is run by a low noise, linear power supply.
When it comes to connecting the Xact S1 Evo to a DAC there is only one option, USB, but there are two such outputs, one with and one without a 5V power line. A few DACs will run without this handshake voltage and are likely to benefit from its absence, most however require it in order to ‘see’ the source, I didn’t have any of the former until the CAD 1543 MkIII came along shortly after the Xact had departed. Most of the listening was done with a Bricasti M11 Classic, a DAC which I later bought largely as a result of the sound it produced with this source.
Sound quality
I hooked up the Xact S1 Evo with a Network Acoustics muon2 USB cable and discovered that it both boots up and closes down rather faster than average, which is a bonus, but when you press play the real bonus hits home. The sense of presence and realism is magical, it feels like the musicians are in the room with you, the atmosphere is electric and it soon becomes very difficult to press pause. With music you like this can only be done at the end of a track, to stop in mid flow would be sacrilege, an insult to the artist even though they’re totally unaware of your actions. There’s such a strong sense of connection that this doesn’t matter, they are speaking and you want to hear everything they have to say, whether there are words or not. Whether it’s the beauty of Tord Gustavsen’s piano or the restraint of Herbie Hancock’s backing on Court and Spark, the level of fine detail presented makes each a special occasion that has to be savoured.
The Xact S1 Evo finds melodies where none were previously apparent, this happened with Nils Frahm’s Right Right Right (Paris) because the contrasts between loud and soft and the tone of the different keys is so well differentiated. Taking the noise floor as low as Marcin has achieved with this streamer opens up so much information that it’s almost uncanny. My notes are strewn with album titles to add to the drive. As usual locally stored music files sound considerably better than those from streaming services and the resolution on offer with the Xact makes this abundantly clear. In practise it means that you can play the music stored on the drive at a higher level than material from Qobuz because perceived distortion is that much lower with the former. That said music streamed from this service still sounds better than usual, a lot better.
Vocals are very powerful things when they come from artists like the Weather Station, the purity of Tamara Lindeman’s high voice on Free is to die for, thanks in no small part to the Xact S1 Evo’s ability to render it in such solid, three dimensional form with not the tiniest hint of thinness. Something that digital systems usually fail to do, here you get what appears to be the full acoustic picture right down to the quietest notes, backgrounds are so dark that all the sparkle in the music is made clear.
This benefits timing too, I have not heard better timing from a digital source, this is not typically a strength of USB connections but the Xact S1 Evo proves that the connection is not a limitation but rather that implementation is, as ever, king. I had the chance to contrast this server/streamer with an alternative that’s nearly as expensive and found that while it was close there was a loss of focus created by relatively blurred transients and higher noise. The price here may be high but I have not heard its match at any price.
Conclusion
The way that the Xact S1 Evo engages both the heart and mind is what makes it so compelling, it achieves this by reducing noise and revealing all manner of detail with extraordinary degree of coherence and the result is more enjoyable, more exciting music that you just don’t want to put down. It’s worth noting that the Xact does all the things that makes a great audio source; it has speed, resolves space, images superbly and has no perceived distortion. But the communication is what makes it so thrilling.
To be frank I haven’t heard a standalone streamer that is as good as the S1 Evo, let alone one that’s a server as well. And having discovered that the Bricasti M11 Classic I used is not quite as good as the CAD 1543 DAC, it is clear that there is more to hear from this remarkable digital source, which makes me even more convinced that it will be a long time before I hear anything better.