Master Fidelity’s new NADAC S Music Server joins the rest of the NADAC stack which includes the NADAC D DAC, NADAC C Master Clock, and NADAC L Line Stage Preamplifier.
NADAC takes timing seriously so the NADAC S is designed to accept a 10 MHz reference from the NADAC C over BNC.
From the press release:
The NADAC S accepts a 10 MHz reference from the NADAC C over a BNC input, or runs from its own oven-controlled crystal oscillator. What distinguishes it is not the presence of that input — reference-clock inputs exist on other high-end servers — but how far the reference travels once inside. Master Fidelity’s custom motherboard distributes reference-derived timing across the computing platform and into purpose-built USB and network interfaces, with power supplies tailored to their roles.
Internal storage comes courtesy of four user-supplied enterprise-grade U.2 SSDs and the NADAC S is delivered running Windows 11 Enterprise LTSC (Long-Term Servicing Channel) but owners can opt to run on Linux. The NADAC S supports a number of apps for playback including Roon, HQ Player, Audirvana, and JPlay. The fan-less NADAC S employs a “self-cooling designed heatsink” for whisper quiet operation.
The Master Fidelity NADAC S Music Server is available now through authorized dealers and is priced at $39,800.
Press Release:
Master Fidelity’s NADAC S Music Server
GTT’s new film explores the server built to share a timing reference with the NADAC D converter and NADAC C master clock. Now shipping in North America.
LONG VALLEY, NEW JERSEY — September 8, 2026 — GTT, Master Fidelity’s North American distributor, today released Episode 160, a filmed conversation with Master Fidelity’s Weishen Xu on the NADAC S music server, which has begun shipping. The NADAC S brings the server into a coordinated front end with the NADAC D converter and NADAC C master clock, extending a shared timing reference into the source itself.
In a conventional computer-based front end, the source and converter can run from independent timing references. A precision clock at the converter does not, by itself, coordinate the clocks throughout the computer feeding it.
The NADAC S is Master Fidelity’s answer to that.
The server joins the system
The NADAC S accepts a 10 MHz reference from the NADAC C over a BNC input, or runs from its own oven-controlled crystal oscillator. What distinguishes it is not the presence of that input — reference-clock inputs exist on other high-end servers — but how far the reference travels once inside. Master Fidelity’s custom motherboard distributes reference-derived timing across the computing platform and into purpose-built USB and network interfaces, with power supplies tailored to their roles.
Master Fidelity describes the resulting NADAC S-to-NADAC D link as a synchronous USB connection carrying small, synchronized packets. The external reference is not the converter’s working clock: it provides the foundation, and the NADAC D’s own Advanced Clock Data Recovery still generates the final conversion clocks demanded by its true 1-bit architecture.
In the film, Xu puts it in plainer terms. A server contains many clocks — the chipset, the network interfaces, the storage path — each running at its own frequency. Left alone, he says, they never talk to each other. Given one reference, they do.
Why timing is worth this much trouble
Master Fidelity’s published technical papers separate short-term jitter from the slower drift known as wander, and illustrate how timing errors can affect noise and distortion. The NADAC C is built accordingly: a selected SC-cut crystal, months of aging and screening, temperature control and carefully engineered distribution. Master Fidelity specifies typical jitter of 66 femtoseconds at the clock’s 10 MHz output, measured across 10 Hz to 100 kHz.
In a February 2024 essay, recording engineer and producer Bert van der Wolf-Oude Avenhuis of The Spirit of Turtle describes advances in clocking that recalled listening directly to his microphones. Discussing the NADAC C, he reports more natural musical attacks, clearer instrument placement and a more seamless presentation.
His conclusion reaches beyond the equipment:
“Having the Master Fidelity clocking technology available to both the recording chain and the playback is a true blessing and makes my work as a producer/engineer a lot more meaningful. It delivers what comes from the musicians in an incredible true fashion, whereby the gateway between them and the listener is ultimately transparent!”
His essay predates the NADAC S and describes Master Fidelity’s clocking technology in recording and playback.
Built for a serious music library
- Clocking: 10 MHz BNC reference input for synchronization to the NADAC C, or internal oven-controlled crystal oscillator.
- Audio and network connections: a locking USB-C port for the NADAC D, two selected USB-A ports, and custom RJ-45 and SFP network interfaces, all on low-noise linear power. The SFP interface ships with an optical-fiber adapter.
- Storage and cooling: an enterprise U.2 system drive, four enterprise SATA SSDs for music, and fanless operation with no moving parts.
- Software: Windows 11 Enterprise LTSC installed by default, with Linux alternatives supported. Master Fidelity validates and stress-tests Roon, HQPlayer, Audirvana and JPLAY among others.
Hear it
The NADAC S is shipping now, in limited quantity, on an order queue. For current pricing, configuration, delivery timing or a demonstration, contact GTT or an authorized dealer. For owners of a NADAC D and a NADAC C, the question is more specific: what changes when the source joins the same timing reference?
Watch GTT Episode 160: the NADAC S conversation: https://youtu.be/LmZnKuIkCds
Explore the NADAC S: official product details: https://www.master-fidelity.com/nadac-s/
Read Bert van der Wolf’s clocking essay: The Importance of an Accurate Clock Signal in Digital Recording and Playback
About GTT
GTT has served serious listeners from Long Valley, New Jersey since 1995 through specialist high-end retail, North American distribution and careful system matching. GTT is Master Fidelity’s North American distributor for the United States, Canada and Mexico.
Company Website: GTT Audio