Jcat Xact S1

[Serafin Sonnier]

Ithink the JCAT XACT S1 music server is a very cool product that ticks nearly every box for what I would want from a product like this or how I would want to build it myself. But at the same time its clearly not designed for every audiophile, its designed for audiophiles who value specific things above others and its for audiophiles who are looking for the absolute best, again for those specific things. I appreciate that sounds vague but bear with me.

I think its important to start with the history of getting to this point because hopefully you will appreciate it more or at least see it better through my eyes. I have been a computer audiophile enthusiast for well over a decade, I was into it before I even realised. My first exposure to accessing a music library on an iPad was a revelatory experience and its something we take for granted today but not way back when. My first real experience of listening to music like this was using a Meridian Sooloos setup, using an MC200 as the source and I later found out it was a computer in a fancy Meridian case. Not that there is anything wrong with that, lots of audiophiles listen to music on computers every day, not just music servers, but phones and tablets are all computers of course too.

Once I realised the Meridian was a computer I became obsessed with building my own, because that meant it could be and do exactly what I wanted. The big motivator for me was Dirac Live and using it as a room correction solution for my HiFi system. At the time running software on a computer was the only way to get Dirac Live that was affordable to me but beyond that the sound quality I was getting from a standard built computer was not great so I started to explore ways to improve things. Over the last 10 years I have tried all sorts and I learnt that sound improvements generally come from three key areas, hardware, power and software believe it or not. I continued my passion up until very recently with my last main build being back 2019 but that computer was continually improved with all the latest and greatest parts, with the most significant of them being a huge linear power supply from JCAT, the Optimo S ATX, the worlds first ATX 100% linear power supply for a computer. Its a monster, its larger and heavier than most power amplifiers and demonstrates the challenge of providing clean, stable linear power for a power hungry by its very nature computer. I made a video about this power supply you can see here

However I think to fully appreciate the S1 you need to remove the lid to look inside and there are several things that really grab your eye. The overall power supply is custom made for the S1 by JCAT and its using a very quality transformer with Nichicon Muse capacitors and a lot of them, as much capacitance as some power amplifiers. There are a number of specific attentions to details that DIYers will love such as the quality of all the cabling, the non standard choice of the specific 4TB SSD for music storage and the really high quality +/- 5 parts per billion OCXO clock and more. So its very high grade parts everywhere.

I do wonder how many audiophiles still doubt the importance of power quality in purely digital products. I have made loads of videos on the topic in the past, even demonstrating sound differences in them with one of my favourites was upgrading an Oppo 4k blu ray player from its SMPS to a linear supply. The Oppo was used just as a CD transport feeding into a Chord Qutest DAC, the sonic difference was remarkable. The video is here and if you check the comments many people inquired as to where they could buy the power supply such is the sonic difference, even audible in a YouTube video using a poor quality on camera microphone. Experiences like this are powerful motivators.

I also feel the layout and navigation of the app is almost perfect, maybe its because I am so familiar with it now but I find in the main its less cumbersome to use than others. I can get to the music I want to listen to really easily and fast but the experience of getting there is still nice. This is definitely aided by just how fast the app is, its so fast everything feels almost instant, you hardly ever see any buffering of album art which drives me mad about any app in 2024.

The app menu system is a little confusing at first and maybe could be polished a little better but you get used to it. There are not a lot of menu options to choose from so its nice and simple to setup and customise what your clicks do but the important options are there such as selecting gapless playback or selecting how you want your music added to your play list.

The second and likely negative with PLAY is its an app for IOS only and that of course wont be great for everyone and worse still for some is the streaming service integration is limited to Tidal and Qobuz only.

Its interesting, I have seen a number of music server manufacturers recently advertise their products as JPLAY certified so this app is making real waves across the market and its very easy to see why once you have used it. Its offering a great experience with your money being used to continually better that experience and stay up to date with the many changes and developments Apple and the streaming services make. That is essential to a long time happy user experience product and its not free to do this so paying for it makes sense.

However for owners of XACT S1 music server it is free, you get a lifetime of free access to the JPLAY app which is cool and I think right given the price because of course the two products are designed to work perfectly together, but they are not exclusive. You could use any UPNP control app with the S1 and JPLAY with any UPNP controllable server or streamer.

There should be one more report this week, and I think especially important for users on this forum, coming from customer who went through a long journey using JPLAY, dedicated PCs with Xeon low TDP CPU, Apacer RAM, Apacer SLC SSD and all upgrades from JCAT including the mighty OPTIMO S ATX PSU.

What I heard in first 30 minutes I never believed that it could be possible. I thought that a pc based build with all recommended parts (supermicro board without graphic, old xeon without grafic 20W TDP, apacer slc ssd ,apacer industry RAM and all of the best jcat products inkl your atx supply) would sound similar to the xact s1 but with less afford and easy usable for every one without computer skills.

I tried several Windows Server versions (2019 - 2016 - 2012) in Core mode and Gui. Contrary to many other opinions, I ended up with 2012 because it just sounded the most natural to me. Yes 2016 has more attack and the bass is more on point (too much?) but overall 2012 has the most natural sound for me.

At the end the sound was really very good ( I thought ). I work in a high-end hi-fi shop in Vienna and have a good overview of what is currently possible on the digital and analog side with the well known brands. I have to honestly say that I am of the opinion that the good old vinyl turntables with really good cartridges and phono amplifiers is still the measure of all things. (for me)

When Marcin then announced the XACT S1, I was of course curious and ordered one to test. I was very skeptical. The small thing can't possibly sound better than my Monster PC setup with the 30 kg ATX power supply S ATX.

Hi Marcin,

Thank you for the details and your work. It is fascinating.

I understand that you have developed a specific version of JPLAY under your own real time Unix OS.

In the Windows version of JPLAY we had many configurations and in particular:

- DAC Link

- XtreamSize

- Bitstream

- etc...

My questions:

Do we still have access to its settings?

Are you running JPLAY with unique settings, if so which ones?

Personally I have the DAC MOLA MOLA TAMBAQUI. I have configured JPLAY with all the extreme options.

Many ups & downs along the way with huge frustrations but, outweighing all of that, the rewards were fantastic. Not being that IT savvy, I have relied on the forum heavily for technical guidance on this journey & the many topics with their contributors without which, I would never have succeeded.

Always happy with my DIY build & in terms of cost & hands down a musical winner. However, from time to time it did let me down, which required intervention on my part to resolve whatever the issue may be. Having had my server for 10 plus years, it came time to decide whether to build a new server or go for dedicated purpose built unit, the latter being decided upon.

I had the demo unit for several weeks & it sounded pretty good. After some communication with the manufacturer, a few tweaks & and software changes, things improved further but with a cost between 7 to 10k depending on options, it was a lot to invest.

After many emails & questions to Marcin I decided to try the S1. Marcin must have got fed up with so many emails & questions but he dealt with all promptly, answering my specific queries in each case.

The S1 duly arrived. Hook up was a breeze. USB, LAN, SD card & power. I had a network issue to start with but all was resolved & again, Marcin was on hand via email, (he was actually on holiday with his family but still took time to answer any queries, so many thanks for that).

I listen to a lot of electronic music & the layering, panning, & detail is excellent. You can just hear further into the mix. This is not forced details, not edgy at all. In fact, compared to my server, the S1 is more natural & relaxed in its presentation yet with detail/plankton in abundance.

Bass is also richly textured allowing more information low down to be heard. Listening to double bass live on a good recording was a revelation. The attack, sustain & decay along with the sound of the strings, the finger board & body of the instrument are all well-defined & make the instrument come alive in your listening space.

I'm thrilled to share that the XACT S1 music server, one of my proud creations, was recently reviewed by HiFi Knights. We appreciate the depth of their analysis, and I'd like to share some highlights for those interested:

3a8082e126