XACT S1. The music server you've been waiting for

JCAT WILL LAUNCH ITS OWN HIGH-END MUSIC SERVER AT AVS 2022 - XACT S1 – FEATURING WORLD’S 1ST 100% LINEAR POWERED MOTHERBOARD.



Designed from scratch, XACT S1, is a purist’s dream for those in the know. Based on JCAT’s ZeNA (Zero-Noise-Architecture) motherboard, the S1 does not rely on switching DC-DC converters. Instead, super-low-noise linear regulators are used exclusively making XACT S1 the world’s first music server running on linear power alone.



The market lacked a genuine audiophile-grade motherboard. Most of the available streaming products are assembled using general-purpose PC motherboards. According to Marcin Ostapowicz, JPLAY & JCAT Founder, such motherboards with noisy switching converters all over the place should not be used in a high-end audio system.



XACT S1’s proprietary motherboard, apart from linear regulation, features extremely low-jitter OCXO clock with ±5 ppb frequency stability. The extensive power supply section based on JCAT’s renowned OPTIMO linear PSU delivers 140 000 uF of capacitance provided by Nichicon’s flagship Muse and Fine Gold capacitors series.



Software is custom made and finetuned personally by JPLAY’s Founder, Marcin Ostapowicz, who promises superb sound quality and ease of use via included brand new JPLAY iOS app which combines Qobuz, Tidal and local content in a single beautiful interface.



According to Wojciech Pacu?a, chief editor of High Fidelity, the sound of XACT S1 is 'insanely difficult to distinguish from an analog source'. Come and hear it yourself.


When: 28-30th October


Where: Warsaw, Poland. Radisson Blu Sobieski Hotel, Room 718

 

Hi all
I am a recent S1 owner and I am wondering how to set these settings. All is working but do they have any influence on sound quality. I am planning via Qobuz, all advice is welcome.

 

Hi all
I am a recent S1 owner and I am wondering how to set these settings. All is working but do they have any influence on sound quality. I am planning via Qobuz, all advice is welcome.

Default settings are best except for Update Time which I’d recommend setting to the highest value of 12000.

So in your case I’d recommend unchecking Safe transition mode and Proxy for Qobuz. These are not required for XACT S1 and not optimal for sound quality.

You can contact me via email or PM if you have any further questions.

Best regards,
Marcin

 

Hey everyone,

I’m excited to share that XACT S1 EVO is the cover story in the latest issue of High Fidelity!



The review is available now in Polish, and the official English translation will be published next month. In the meantime, if you’d like to check it out, you can read it here:
https://www.highfidelity.pl/@main-4892&lang=

Best regards,
Marcin

 

Hey everyone,

I’m excited to share that XACT S1 EVO is the cover story in the latest issue of High Fidelity!

View attachment 144705

The review is available now in Polish, and the official English translation will be published next month. In the meantime, if you’d like to check it out, you can read it here:
https://www.highfidelity.pl/@main-4892&lang=

Best regards,
Marcin

Marcin, I can’t possibly wait another month—I’m way too curious about what they discovered with the XACT S1 EVO!

Excerpt from Review
Author: Wojciech Pacuła, High Fidelity, Issue No. 250, February 1, 2025
(Unofficial English translation, using Google Translate and ChatGPT, with an emphasis on maintaining audiophile nuance.)

(…) In the sound of the tested device, something stands out—something rarely encountered in file-based playback devices: a combination of warmth and energy. Looking at the device with a critical ear, one could say it still doesn't reach the resolution I get from CD and SACD discs. It was similar with the S1. But now, this difference feels significantly smaller. I know it’s there—you can hear it in the slightly rounded attack of the notes and the soft curvature of their decay. But even so, it carries little weight.

This is because we simultaneously get a fullness of sound that even Ayon’s player can’t drive as deeply. A shock? Maybe not quite, but certainly a surprise—and a respect that comes from understanding this shift. Pat Metheny’s guitar on Our Spanish Love Song from the album Beyond The Missouri Sky (Short Stories), ripped from the Japanese UHQCD release, had a gentleness and depth that made the instrument sound more tangible, almost within reach. The strings resonated with a natural decay, and the interplay between Metheny’s subtle phrasing and Charlie Haden’s bass created an intimate, immersive soundstage. The timbre was rich, with a slight warmth that didn’t overshadow the micro-details—every nuance of the fingerwork and string vibration was present, yet never clinical.

This device doesn’t strive for hyper-analytical precision. Instead, it offers a presentation that feels organic, engaging the listener emotionally without sacrificing technical prowess. The spatial positioning of instruments was precise, but it was the coherence and flow of the music that truly impressed. It’s a sound that invites long listening sessions, where the technical aspects fade into the background, and the music simply is. (…)

 

The High Fidelity review is now available in English: https://www.highfide...in-1462&lang=en

Also I'm proud to share that a fantastic new review of the XACT S1 EVO music server by Jason Kennedy was just published in the latest issue of HIFI+ magazine (available in print and digital)




Best regards,
Marcin

 

Good morning. I will be using the XACT S1 EVO in my room at the upcoming SouthWest Audio Fest (SWAF). It will be in the Peridot room on the Mezzanine. Come by to listen to some fantastic music played by the XACT streamer.

 

Hello Marcin, congratulations for these nice new reviews ! What about your N1 Network Switch ? Will it be launched during Munich High End?
By the way do you see it as a way to improve sound quality when using your S1 Evo? On your website there is a OPT BRIDGE 1000M OPTICAL ISOLATOR. So what would be the perfect complement to your Evo, apart from using 2 S1, with one as a switch, considering cost?

 

Hello Marcin, congratulations for these nice new reviews ! What about your N1 Network Switch ? Will it be launched during Munich High End?
By the way do you see it as a way to improve sound quality when using your S1 Evo? On your website there is a OPT BRIDGE 1000M OPTICAL ISOLATOR. So what would be the perfect complement to your Evo, apart from using 2 S1, with one as a switch, considering cost?

Hello,

Thank you.

The N1 switch is coming very soon.

Yes, it is the best way to improve clarity and resolution with the S1 & S1 EVO music servers. One of the dealers who is fortunate to have a pre-production unit and using it with dCS Varese said it's one of the best upgrades he's heard in digital audio, ever.

Best regards,
Marcin

 

New Software Update for XACT S1 & S1 EVO



I'm pleased to announce a new software update for the XACT S1 and S1 EVO. This update brings two key improvements:

✔ Enhanced Sound Quality – Experience even greater precision and naturalness in your music.
✔ Easier Music Transfer – You can now upload music files over the network without entering a password.

The update is free of charge and recommended for all units. Contact XACT Audio for the instructions how to update.


Best regards,
Marcin

 

I have been playing with my S1 for 6 weeks now and I must say I am enjoying it a lot. The Jplay app is very nice with its Qobuz integration. Sorry I am not good in discribing its sound but agree with what others have said before. It’s so musical, relaxed and dense sound.

 

Hi Guys,

I recently had the honor of participating in a truly special event — the 150th meeting of the Krakow Sonic Society!

This milestone gathering featured an in-depth listening session with the XACT S1 EVO music server, powered by JPLAY. The S1 EVO was directly compared to the Aurender N20 in a relaxed but critical listening environment.
The verdict?
The S1 EVO impressed even the most seasoned audiophiles present, with its resolution, natural timbre, and effortless presentation. It held its ground confidently against the well-respected N20.
For those interested in a detailed write-up of the Krakow Sonic Society event, High Fidelity has published full coverage here:
Krakow Sonic Society №150 – High Fidelity


This listening session comes at a great moment, as both the S1 and S1 EVO have recently received numerous outstanding reviews and awards in the press, including:

Grand Frisson 2025 for the S1 from 6moons:
6moons review

The Ear Editor's Choice for the S1 EVO:
The Ear review

REMARKABLE! from VUmètre for the S1 (VUMETRE N°56)

«REFERENCE» award from Haute Fidélité for the S1 (April 2025)


Clearly, there’s a lot of love for these machines!

And one more exciting piece of news — the long-awaited XACT N1 network switch will finally be available within the next 24 hours! I’ll share full details in a separate post soon.

If anyone has questions about the XACT S1 EVO, the listening session, or the upcoming N1 switch, I’m happy to share more insights!

Best regards,
Marcin

 

And one more exciting piece of news — the long-awaited XACT N1 network switch will finally be available within the next 24 hours! I’ll share full details in a separate post soon.

If anyone has questions about the XACT S1 EVO, the listening session, or the upcoming N1 switch, I’m happy to share more insights!

Best regards,
Marcin

Found it!

The SFP port is part of the main LAN circuitry and shares a common ground with the standard LAN ports.
A typical use case for the Nl's SFP port is connecting it to an SFP-capable router via a fiber optic cable. In most routers, SFp ports are directly linked to the router's processor, allowing you to bypass the often low-quality and noisy Ethernet switch section. This can significantly improve your system's sound quality.

Question : Does N1 come with an SFP transceiver? If not, which one would you recommend? What do you use yourself @Marcin_gps ?

Thanks and good luck with the launch!

 

Found it!



Question : Does N1 come with an SFP transceiver? If not, which one would you recommend? What do you use yourself @Marcin_gps ?

Thanks and good luck with the launch!

I started a new topic for the discussions about the N1 switch, let's discuss over there: https://www.whatsbestforum.com/thre...promise-network-switch-for-audiophiles.40739/

SFP module is not included. I am using Finisar FTLX1475D3BTL

Best regards,
Marcin

 

I started a new topic for the discussions about the N1 switch, let's discuss over there: https://www.whatsbestforum.com/threads/why-we-built-the-xact-n1-–-a-no-compromise-network-switch-for-audiophiles.40739/

SFP module is not included. I am using Finisar FTLX1475D3BTL

Best regards,
Marcin

Thank you, Marcin! I’ve just added your information to my posts in the Best Audiophile Switch thread.

 

Has anyone tried the new OS? I haven’t read any comments yet.



I did and I like it, I think it’s a pretty good step up in all aspects.

All though not at first. When I first listened to the new OS I was shocked there was more detail all right but it was pretty harsh and had too much treble energy which resulted in a underwhelming mid range. So I listened for a few days thinking what the hell is this, this can’t be it. I asked Marcin for a second SD card with the old OS on it so I could compare them better. I didn’t listen for a few days but just before the new card arrived I got an idea during a sleepless night. I play in my living room so acoustic treatment is problematic, I have a few big acoustic paintings and one glass wall with extra heavy curtains in front of them for now but I am not finished yet. I also bought a PSI AVAA C214 it’s not that big, you can put a plant on it so it doesn’t stand out at all. For some reason it was not working properly, if you put your hand in front of it’s microphone it didn’t start feedback the signal. So the problem was I had way too much reflection/ reverb in my hard surfaced living room.

So what I think of the new OS is it has more details with better nuance, better nuanced decay but still with the same overall naturalness and organic sound it had before.

Well done Marcin.

 

Has anyone tried the new OS? I haven’t read any comments yet.



I did and I like it, I think it’s a pretty good step up in all aspects.

All though not at first. When I first listened to the new OS I was shocked there was more detail all right but it was pretty harsh and had too much treble energy which resulted in a underwhelming mid range. So I listened for a few days thinking what the hell is this, this can’t be it. I asked Marcin for a second SD card with the old OS on it so I could compare them better. I didn’t listen for a few days but just before the new card arrived I got an idea during a sleepless night. I play in my living room so acoustic treatment is problematic, I have a few big acoustic paintings and one glass wall with extra heavy curtains in front of them for now but I am not finished yet. I also bought a PSI AVAA C214 it’s not that big, you can put a plant on it so it doesn’t stand out at all. For some reason it was not working properly, if you put your hand in front of it’s microphone it didn’t start feedback the signal. So the problem was I had way too much reflection/ reverb in my hard surfaced living room.

So what I think of the new OS is it has more details with better nuance, better nuanced decay but still with the same overall naturalness and organic sound it had before.

Well done Marcin.

Thanks for sharing your impressions! I'm glad you're enjoying the improved sound from the new OS update. This isn't my final word, though—I'm currently working on further enhancements that I'll be able to share later this month.

Stay tuned!

Best regards,
Marcin