Hifi - 2019.01.08
HD DAC X HD PSU front modulometer peclette da converter analog ditigal light

The HD DAC X is a strong evolution of the world-acclaimed Nagra HD DAC.


The result is a life-like sound with warmth, texture, extreme dynamic and extended frequency response beyond what was ever achieved by other D/A converters.


The power supply is extremely sophisticated, using ultra-fast silicon carbide rectifier diodes, ultra-low-noise voltage regulators, and a virtual battery made up of a supercapacitor bank three times larger than the one of the HD Preamp. The new HD DAC X includes no less than 37 regulated ultra-low noise individual power supplies.


The HD DAC X features AES-EBU, S/P-DIF on both RCA and BNC, 2x Nagra Link single-mode ST-1 optical inputs to receive future Nagra high resolution sources. The USB input uses a proprietary software designed around an 8-core X-Mos chip.


Ultra-high precision and ultra-low jitter clocks are used in this new Nagra HD DAC X. A high-performance FPGA performs all internal calculations. Every input signal is converted into DSD 256 format (11.2 MHz sample rate).


The main digital power supply has a noise level 30 times lower than the HD DAC, itself already using very low noise circuits. The order of magnitude of the noise of these new power supplies is 0.4 to 0.8 µV rms (from 10 Hz to 100 kHz). The digital part alone uses 16 ultra low noise power supplies. The digital input and D/A board is built on an 8-layer high-precision PCB.


The analog section is quite unique. The proven solutions adopted for the Nagra HD DAC have been taken over and improved. Like the HD PREAMP, it uses a dual-mono topology. The analog signal coming out of the D/A board is taken to a symmetrical current amplifier that dramatically lower its impedance. This unique stage bears very special performance with a rise time in the order of 1800 V / µS into the 28 H inductive load of the inter-stage transformers. It makes no use of feedback nor it provides any gain.

The voltage gain is only achieved by a new generation of Nagra transformers. The other role of these transformers is to unbalance the audio signal to attack a single-ended tube stage. These transformers are built exclusively in Nagra workshops in Switzerland, by our specialized and skilled transformer operators. The performance of these transformers is key to the global quality of this new Nagra D/A, they are the object of severe quality controls.


Following the transformers, the impedance is further lowered by a stage consisting of two NOS military tubes JAN5963 (one per channel). This stage makes use of a cathodyne output design. The heating filaments voltage is individually regulated for each tube to achieve a very low self-noise. This stage is designed to have no feedback. Numerous special components, some of which are custom-built according to Nagra’s specifications, are used within this section.


Nagra mechanical engineers have adapted the newly designed vibration free stand of the HD Preamp to lower the microphonic resonances to a new level.


The HD DAC X was launched at the last Rocky Mountain audio fest and got five Best Sound of Show.


..Of all of them, a hi-resolution 2xHD Storyville Records remaster of either Sonny Boy Williamson’s The Blues or The Sky is Crying, (DSD 256) the latter recorded when he was perhaps 66 years old, blew me away. The intimacy of the recording, the huge contrast between the man’s aged speaking voice and still intact, surprising sweet singing voice left me breathless. Jason Victor Serinus, Stereophile



A track from a DSD-only release of Carmen Gomes Sings the Blues also sounded superb. And if that were not enough, a beautiful sounding 1948 recording of Peggy Lee, rescued from acetate masters … left me in a state of wow.

Hot on the heels were Nagra/Rockport, Julie Mullins’ Best of Show :

Speaking of superb sound and standout demo material, Nagra introduced its new HD-DAC-X ($65k) in a setup with its other HD-line electronics, a vintage Nagra tape deck, and Rockport speakers. René Laflamme presented myriad well-recorded tracks ranging from Norah Jones’ new live album (upsampled to DSD256) to Sonny Boy Williamson, plus rare gems, such as a digital file transfer of a mono recording of Peggy Lee singing “Bye, Bye, Blackbird” from 1948, where her voice displayed a more earthy naturalism compared to her vocal styles on later material… few show-goers walked in and exclaimed, “Now, we’re talking!”


13 answers on "NAGRA HD DAC X"

  1. Dante Lucifer,

    Beautiful product and awesome design

  2. Shahril Tan,

    The DAC is designed to Stack On Top of the Power Supply?What is the dimension of the HD X when stack on top of the Power Supply… Height,Width and lenght.. Thank you

  3. David Tsui,

    I recently purchased the HD DAC-X and I’m trying to pair it to a power conditioner. Can you tell me what is the maximum power consumption of this unit? I can’t find it anywhere. Thanks.

    1. Tanguy Lemaire,

      Dear Sir, the maximum power consumption is 170W max. You can also find this information page 22 of the User manual.

  4. Bernd Dworrak,

    Dear Sir,
    you wrote “… A high-performance FPGA performs all internal calculations.”
    Would you mind telling us which FPGA you’re using.
    Thanx in advance

    1. Tanguy Lemaire,

      Hello. This is no secret, but it is not either an information we will publish. We might use an FPGA today but change it overnight for a better one, or if a component becomes unavailable. The critical part is the software in this case.

  5. Jon Caruncho,

    Does it have a volume control?

    1. Tanguy Lemaire,

      No, no volume control on the HD DAC X.


    Hello, could you share some THD+N measurements taken on the analog output of the dac? Congrats for the beautiful product.

    1. Tanguy Lemaire,

      Thank you for your request. There is a lot to say about the importance and relevance of THD + N.
      We do many other measurements that provide more information about the real quality of the design.
      More important than all, once the measurements are correct, we do extensive listening sessions and we improve our designs.
      Then again measurement, listening, improvement in circle, until we reach the quality we want.
      Right now, we do not have available the HD DAC X measure, it is in a special measuring computer linked to our Audio Precision rig.
      Here we share the measurements for the Nagra HD DAC Output noise, maximum volume, no weighting filter, reference level 1.30 V RMS on logarithmic scale.

      Nagra HD DAC Output noise, maximum volume, no weighting filter, reference level 1.30 V RMS on logarithmic scale

  7. Siegfred Manalo,

    Why does Nagra HD Dac X cant unfold MQA ?

    1. Tanguy Lemaire,

      Dear Sir,
      Thank you for your interest in our products.
      There are many audio formats available today, from Red Book CD to super high resolution.
      Our D/A converters, can play almost all of them without restrictions.
      In fact Nagra was the first company to introduce high resolution recorders in 1992 with the Nagra D & DII and its 96 / 24 bit capability.
      Our new range of D/A converters, from CLASSIC DAC to HD DAC X work the signal at a super high resolution (multiple DSD) with a proprietary algorithm and they make the most of all incoming signals, whatever their resolution.
      Clearly we do not see the technical benefits of including MQA.
      It might be interesting as a compression solution to stream sound.
      However, to play files, we just don’t see the interest for our customers and equally important to the world of Musicians and Record Companies.
      On the other hand, most sources can transfer MQA into PCM so bridges are possible.
      Today the internet bandwidth is increasing and there are other free formats that allow great streaming quality.
      We hope this answers your question, let us know if you have other concerns.
      Musically Yours…

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