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Audio-gd NFB-28

  • Fully balanced design built by discrete analog stages without any OPA and coupling caps in the signal channels, built in real balanced DAC, output for headphone (4-pin XLR or 1/4") and  DAC (fixed output) with preamp (variable output).

    - Non-feedback ACSS analog output stage.
    - LED display avoids RF disturbance for better sound quality.
    - Large R-core transformers and Hi-fi grade parts like DALE resistors, WIMA caps.
    - Total of 6-group PSUs are used to purify the power supply , the analog amp has discrete PSU power supply.
    - Four-channel digitally controlled relay-based volume control to avoid channel imbalance and improve sound quality. 
    -80 steps volume level control in both high gain mode and low gain mode.
    - 160-step volume control ensures smooth control of the volume level.
    - 4 digital inputs:   Coaxial RCA / Coaxial BNC /  Optical / USB
    - 2 analog inputs:  XLR / RCA
    - DAC output:   XLR / RCA / ACSS  (User can set either variable output level as preamp or fixed output level as dedicated DAC).
    - Headphone output : 4 pin XLR / 1/4" (6.3MM) SE.

Recent Reviews

  1. TheChillburger
    A balanced Sabre DAC/amp at a good price
    Written by TheChillburger
    Published Jul 10, 2015
    Pros - balanced amp and DAC, tons of power on tap, lots of outputs and inputs, remote, build quality
    Cons - some issues with source switching, expense of balanced setup
    Hello, I noticed there aren't many reviews of the NFB28 on Head-Fi, and as a big fan of the unit, I felt that it deserves more praise. I will preface in saying that this is the first balanced DAC and amp that I have owned, and the unit was purchased second hand from another Head-Fi member. Kingwa was gracious and allows for warranty transfers, so big shoutout for that!
    Build Quality:
    The NFB28 makes a pretty big first impression with the size and weight alone. It's far more hefty than my previous amps and DACs, with a solid aluminum chassis. The potentiometer is a stepped potentiometer, and it feels great to use compared to my other analog volume pots. The satisfying click for each rotation makes it very easy to dial in the volume just right. Aboslutely nothing wrong in terms of overall construction. While it may not be as beautiful as something like the Oppo HA1, the unit is simple looking and straightforward. 
    The digital inputs on the NFB28 feature a USB, optical, coaxial, and I2S, while the analog in features RCA and XLR. Outputs include TRS and 4 pin XLR for headphone output, as well as RCA and XLR line out. All in all, the unit has more than enough inputs and outputs for myself. The unit can decode DSD, but my library is entirely Redbook format, so I didn't test many exotic file formats with the DAC. 
    There is also a cheap plastic remote that works well. You can purchase a nicer metal one, but that was not included with my unit. 
    My headphone stable includes the HD600, HE400i, and Alpha Dog as the main hifi trio. Most of my listening was done through the single ended input until my balanced cable supplies get in. 
    I was a bit worried about the sound signature of this amp, since it has a reputation as one of the smoother implementations of the ES9018 DAC. But lo and behold, I definitely don't feel like I'm missing detail compared to my very neutral O2. The bass in particular with my planars seems to be a bit more controlled in my ABX testing, but it was definitely not a scientific comparison. The highs and mids do not disappoint either, it doesn't seems like any particular part of the frequency response was compromised here. 
    My main reason for getting this amp was for the insane amount of power on tap in the balanced input. I have just recently made a balanced cable for my HD600, and the power difference is pretty darn huge. I'm not sure how different it actually sounds compared to the SE output, but I willl test that in the future. For now, I at least know that I have the option of going with harder to drive headphones in the future. 
    All in all, I'm very impressed with my first Audio GD product. It has every feature I need, sounds great and is built great. Balanced amplification may not be entirely necessary for good sound, but I figured since I wanted to get a unit with tons of inputs and outputs, I may as well go all out. In the end, this amp is a beast and well worth your consideration as a balanced amp / DAC. 
    1. View previous replies...
    2. TheNoose
      Any updates on listening tests for us here?
      TheNoose, Mar 28, 2016
    3. gorbek
      Hi Chillburger, thanks for the review.

      Im particularly interested with your experience using the Alpha Dogs on this amp, both unbalanced and balanced. Are they a good pairing? How is the bass (particularly when using balanced?)

      gorbek, Apr 20, 2016
    4. AndyDandy
      Hey could you tell me how much you bought it for? I'm considering buying one in the future...
      AndyDandy, Feb 9, 2017
  2. 1Infinity
    Full performance
    Written by 1Infinity
    Published May 3, 2015
    Pros - Trasparent, dinamic, power, perfect pre-amplifier
    Cons - I find none
    sorry my English is Google translate

    [SIZE = 4] I bought this machine to see if such facilities exist hifi quality level beyond which the feeling of fidelity sound becomes real.
    Unfortunately, I'm afraid I have sold too soon because some headphones were dull and boring even using different amplifiers.
    Nfb 28 just catcher my attention to listening, the sound is quicksilver even at low volumes, the ability to be detailed is not inconsistent with that of being musical.
    When I stuck my headphones for the first time I said to my friend: "seems to connect a krell ksa80 headphones but without that annoying lodness".
    I knew who he was until after King Wa !.
    So ok the Dac is great, ok the Headphone Amp section is what I dreamed of, let's plug it in to my balanced Amp Melos triode 200 plus jumping good audio Sp9 Research.
    Damn sound sosi elegant I heard only with Mark Levinson 38s!
    I can no longer connect Audio Research Sp9 I love ..... sic. [/ SIZE]
    I tried with these headphones:
    AKG K701 mod bass + recable balanced ..... fantastic!
    Hifiman 400 Balanced
    Beyerdinamics dt880 600ohm
    Denon d2000 yet to be processed

    In any case, the balanced mode added micro contrast and control as well as raw power without being cold ..

    Ho comprato questo apparecchio per capire se come per gli impianti hifi esiste un livello di qualità oltre il quale la sensazione di fedeltà del suono diventa reale.
    Purtroppo temo di avere venduto troppo presto alcune cuffie proprio perché risultavano spente e noiose anche utilizzando diversi amplificatori.
    Nfb 28 semplicemente cattura la mia attenzione all'ascolto, il suono risulta argento vivo anche a volume basso, la capacità di essere dettagliato non contrasta con quella di essere musicale.
    Quando ho attaccato le mie cuffie per la prima volta ho detto ad un mio amico:" sembra di collegare un krell ksa80 alle cuffie ma senza quel fastidioso effetto lodness".
    Ho saputo solo dopo chi era King Wa!.
    Quindi ok il Dac è ottimo, ok la sezione Amp cuffia è quello che sognavo, proviamo a collegarlo in bilanciato al mio Amp Melos triode 200 plus saltando il buon audio Research Sp9.
    Accidenti un suono sosì elegante l'ho sentito solo con Mark Levinson 38s!
    Non riesco più a collegare L'audio Research Sp9 che adoro.....sic.

    Ho provato con queste cuffie:
    Akg k701 mod bass + recable balanced
    Hifiman 400 balanced
    Beyerdinamics dt880 600ohm
    Denon d2000 ancora da elaborare

    In ogni caso la modalità bilanciata ha aggiunto micro contrasto e controllo oltre che potenza bruta senza essere freddo..


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