FAQ

Please refer to https://www.master-fidelity.com/sales/ or https://www.master-fidelity.com/contact/

Master Fidelity, operating as Merging Fidelity Inc., is a highly esteemed Canadian company established in 2015 in Vancouver, BC, Canada, dedicated to creating and delivering premium high-fidelity audio products that cater to both audiophiles and professional users.

Master Fidelity, originally founded in 2015 as Merging Fidelity, has been actively participating in the development of the first NADAC range under the Swiss brand Merging Technologies.

Since 2022, after Merging Technologies was acquired by the German group Sennheiser and discontinued the NADAC range, Master Fidelity has taken over the NADAC brand and based on its solid expertise, specially in chip design and clocking, developed a completely new range, the MF NADAC range, bringing audio quality to new heights.

If you are located in the United States, Europe or Japan, please contact the local distributor listed in https://www.master-fidelity.com/sales/. If from another territory, please contact Master Fidelity directly as referred in https://www.master-fidelity.com/contact/.

Please refer to https://www.master-fidelity.com/news/

NADAC D’s USB port supports the standard UAC 2.0 protocol (USB Audio Class 2.0), allowing direct plug-and-play operation on Mac OS without requiring any driver.

NADAC D’s USB port supports the standard UAC 2.0 protocol (USB Audio Class 2.0) and can be used on Windows OS using the Windows driver provided by MF, available in the resource section of the NADAC D page: https://www.master-fidelity.com/nadac-d/#resources Currently, NADAC D supports Windows 10 64-bit and Windows 11 64-bit. It also supports Windows 7 32-bit/64-bit and Windows 8/8.1 64-bit, but since Microsoft has discontinued support, compatibility issues may occur. You’ll need to test your system carefully before choosing the correct version.

NADAC D’s USB port supports the standard UAC 2.0 protocol (USB Audio Class 2.0), allowing direct plug-and-play operation on Linux OS without requiring any driver.

A Resync Delay setting of 1000ms is recommended to allow NADAC D to properly reconfigure when changing from PCM to DSD.

If using a USB connection, the source device must support the UAC 2.0 protocol (USB Audio Class 2.0). The NADAC D hardware supports up to PCM 384kHz/32bits and DSD512.

If using Coaxial, Toslink or AES connection, the source device port must comply with the S/PDIF protocol, and should support up to 192kHz/24bits or DoP64.

A Resync Delay setting of 1000ms is recommended to allow NADAC D to properly reconfigure when changing from PCM to DSD. This setting is available in Roon Settings > Audio > NADAC D > Device Setup.

If using a NADAC C along with NADAC D, it is recommended to use a CD Transport having a 10MHz or WordClock input and connect it to one of the NADAC C outputs, so the clock signal is carried along to the NADAC D through the AES output.

It is recommended to use a CD Transport with gapless playback for a good user experience.

Some CD transports generate a clock interrupt with each track change, causing the NADAC D to relock the signal each time, resulting in a poor user experience. These should be avoided if possible.

AES, Coaxial or Toslink are formats carrying their own clock signal along with the audio signal to the DAC and therefore the external clock input feeding the DSC is bypassed in this case. It is then important to clock any source connected through AES, Coaxial or Toslink with the NADAC C if present to ensure its signal is carried along through these formats as well. It will also significantly improve the source audio quality.

It’s recommended to connect the cables before turning on the system and to fully warm up the NADAC C. This can take up to 5 days for a full warming up, however the NADAC C will perform exceptionally well already after a few hours of warming up.

NADAC D should be set to external volume control in the NADAC D settings to output 0dB at all time to the NADAC L.

NADAC D should be set to external volume control in the NADAC D settings to output 0dB at all time to the preamplifier.

It is highly recommended to choose NADAC L as preamplifier for NADAC D for a matching audio quality and user experience.

NADAC D can be connected directly to a power amplifier, it enjoys its own internal volume control.

However, as NADAC D is a high-performance digital-to-analog converter, to achieve the best sound quality, it is recommended to use a preamplifier, such as NADAC L, between the NADAC D and the power amplifier to properly match the levels and enjoy a higher level of ergonomics.

NADAC D is using the True 1-bit technology, requiring extremely good clocking and power supply thermal stability. This makes NADAC D unique and allows it to produce sound quality as close as Analog as it can be.

Please find details on the True 1-bit technology on https://www.master-fidelity.com/nadac-d/

Please refer to https://www.master-fidelity.com/nadac-d/#specifications

Strictly speaking, the clock driving NADAC D’s 1-bit DAC comes from the [MF Advanced Clock Data Recovery System] , not directly from the NADAC C.

The NADAC C’s 10 MHz master clock serves as the reference foundation. However, we still need the clock recovery module because it performs essential tasks like removing residual jitter, aligning timing between clock domains, and generating the exact multi-channel clock signals required by the 1-bit architecture. So rather than being redundant, the clock recovery system is a necessary final stage that ensures absolute precision.

In the AES protocol, the audio clock signal is embedded and carried from the source device. In NADAC-D, the AES input retrieves this clock signal and routes it into our [MF Advanced Clock Data Recovery System], which synthesizes a new, high-quality internal clock that drives the DAC.

With USB, things are quite different. USB audio transmissions do not carry a stable clock from the source. Instead, our [MF ZERO-ppm Sync Synthesizer] generates an Audio Master Clock for the USB Audio (UAC) system based either on the internal NADAC D clock, or on the NADAC’s external 10 MHz reference clock if present. This master clock, together with audio data, is then sent to the [MF Advanced Clock Data Recovery System], which synthesizes the precise clock needed by the DAC.

So regardless of whether the incoming signal is AES or USB, all clock paths converge into the ‘MF Advanced Clock Data Recovery System’. This is crucial because the true 1-bit DAC architecture in the NADAC requires multiple clock channels and is extremely sensitive to timing precision. Thus, our clock recovery system goes far beyond merely eliminating jitter—it manages the precise timing relationships between all clocks and data signals to preserve sonic integrity.

Please refer to https://www.master-fidelity.com/wp-content/uploads/2025/03/NADAC-D-Block-Diagram-1.pdf

The primary purpose of the NADAC C’s 10 MHz reference is to reduce long-term timing variations such as wander and drift, thereby maintaining the fundamental sonic quality of the system. The  locks onto this 10 MHz baseline and further refines it to generate the final Audio Master Clock that drives the DAC.

A useful analogy might be loudspeakers: no single speaker can perfectly cover 20 Hz to 20 kHz without compromise. Likewise, no single clock can be flawless across all performance dimensions. That’s why we use multi-stage processing to harness the strengths of different clock circuits and components, ultimately producing a clock signal as close to perfect as possible.

This multi-stage methodology is similar to practices in high-end measurement equipment—for instance, crystal oscillator phase noise analysis systems, where multiple specialized circuits are cascaded to achieve the best performance.

Most of the competition clocks on market, being atomic clocks, ordinary active crystal oscillators, temperature-compensated crystal oscillators, and oven-controlled crystal oscillators, are focusing on frequency accuracy.

NADAC C unique mastery is about low jitter and low phase noise which is the fundamental factor impacting sound quality and key a proper True 1-bit Digital to Analog conversion as implemented in NADAC D.

Please refer to https://www.master-fidelity.com/nadac-c/ as well as the Q&A below.

Please refer to https://www.master-fidelity.com/nadac-c/#specifications

There’s no strong correlation between jitter and frequency accuracy. Many people confuse jitter with frequency accuracy, believing that higher frequency accuracy means better sound quality. This is a misconception.

Jitter refers to the short-term instability of a clock signal in the time domain, manifesting as random or periodic deviations of signal edges relative to their ideal timing. Simply put, it’s the difference between the actual transition time and the ideal time.

Frequency accuracy refers to the long-term deviation of the output frequency from the nominal frequency (or ideal frequency), usually expressed in ppm (parts per million). It reflects the “absolute accuracy” of the frequency.

For digital audio applications, jitter performance is crucial for sound quality, where frequency accuracy, below 0.1ppm typically, has negligible impact on sound quality.

Jitter and phase noise are essentially manifestations of the same physical phenomenon in two different domains (time domain vs. frequency domain), and they can be converted to each other through mathematical transformations. In a nutshell, phase noise is the “spectral view” of jitter in the frequency domain, while jitter is the “accumulated result” of phase noise in the time domain.

It is therefore important to note that phase noise requires an offset frequency range, and jitter also requires bandwidth for meaningful test results. For example, for audio applications, phase noise needs to cover a wider range, such as 1Hz to 100kHz offset. Similarly, the jitter test bandwidth should also meet the requirements of the audio application. Many audio devices use jitter bandwidths specified in the communications field. For example, a typical jitter bandwidth in the communications industry is 10kHz to 20MHz, which is too low for audio applications, making this jitter value meaningless.

Building on the efforts of Master Fidelity to design solutions based on custom made Digitally controlled Analog components, NADAC L has been imagined in this perspective, not only to offer unique features but also to maintain the NADAC D exceptional sound quality output in the following audio chain up to the Amplifier.

Please refer to https://www.master-fidelity.com/nadac-l/

Please refer to https://www.master-fidelity.com/nadac-l/#specifications

Not at all. NADAC L is a digitally controlled analog preamplifier. Its audio signal path for volume adjustment is 100% analog, while digital circuitry is used only for precision control and monitoring. This unique design ensures that the sound remains absolutely authentic and pure. The Peak Level Meter employs an ADC to sample the incoming signal voltage and display it on the screen, allowing safe signal monitoring during mute, source switching, or output operations—effectively reducing the risk of operational errors. Inside the NADAC L, the analog and digital domains are kept strictly isolated, while input signals are further safeguarded by a Permalloy audio transformer, ensuring exceptionally high immunity to interference. In short, the NADAC L delivers a full analog volume path, with digital technology serving only for control and metering—guaranteeing the most faithful, transparent, and uncompromised sound reproduction.

Conventional digitally controlled volume schemes usually fall into three categories:

1. Potentiometer + Stepper Motor – Simple and easy to control, but prone to left–right channel imbalance and limited separation.
2. Relay Array – Preserves signal integrity, but frequent relay switching produces audible clicks and high-frequency noise.
3. Electronic Volume Chips – Inexpensive and simple, but their integrated resistors lack the quality of discrete precision parts, introducing coloration.

NADAC L rejects these compromises. Instead, it is built around a full analog signal path, ensuring high precision, ultra-low noise, and uncompromised signal integrity

NADAC L uses a custom-designed electronic switching chip developed by the MF engineering team and fabricated at a leading European IC foundry using a special low-noise process. Functionally, it is a click-noise-free alternative to mechanical relays, combined with ultra-low TCR precision resistors for pure, transparent performance. With thermal drift reduced to virtually zero, the volume remains stable even during adjustment. By contrast, typical electronic volume chips rely on polysilicon resistors with thermal drift up to 400 ppm, whereas NADAC L’s discrete resistors achieve only 2 ppm. In essence, NADAC L provides 100% analog, noise-free, and coloration-free volume control, maintaining the most faithful and transparent reproduction.

NADAC L is not a product created in isolation. Its two lead designers previously developed audio analyzers and studio-grade monitor controllers. This deep background means that NADAC L is both a technical and artistic achievement, excelling in objective measurements and in subjective listening. As a result, it stands as a fully analog preamplifier that balances engineering precision with musical expression.

The analog stage of the NADAC L is powered by a high-performance linear transformer power supply. In practice, less than 10% of its rated capacity is used, guaranteeing ample headroom for stable dynamics and ultra-low noise. For the control stage, a high efficiency switching power supply is employed. Digital circuits demand higher current, and transformer power would raise internal temperature, conflicting with the low-heat design. By isolating the switching supply and preventing interference, NADAC L ensures that the full analog audio path remains pristine, while digital control remains efficient and thermally stable.

NADAC L uses AC input coupling with ultra-low dissipation factor film capacitors, carefully matched for precision. Each capacitor pair is measured using a Keysight E4990A impedance analyzer across the 20 Hz – 1 MHz range to ensure channel consistency. This meticulous process guarantees perfect left–right channel matching and absolute transparency, preserving the integrity of its full analog signal path.

At –8 dB, a rarely used setting, the NADAC L engages a hardware relay using a “gear-shift” concept borrowed from precision measurement instruments. This ensures that even under conditions of high attenuation, the signal path maintains ultra-low noise performance. It is one more safeguard ensuring that the full analog path remains uncompromised at every level setting

NADAC L is designed as a pure attenuation preamplifier. Modern DACs and phono stages already deliver sufficient voltage output; the primary role of a preamplifier is to attenuate the signal to match amplifier sensitivity, not to amplify it further. By remaining 100% analog and focused solely on precise attenuation, the NADAC L avoids unnecessary amplification that could compromise sound quality.

NADAC L offers five different modes specifically designed for advanced systems supporting bi-amp and tri-amp configurations with ease. This makes it ideally suited for multi-driver loudspeaker setups and complex high-end systems. In practice, this means that NADAC L can integrate seamlessly into demanding installations while preserving the integrity of its 100% analog architecture