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NFB-7.1
Sabre32 ES9018 DAC chip
ACSS/XRL/RCA output balanced DAC
 AES / Coaxial / BNC / Optical
Supports up to 32Bit/192KHz*
Price: USD1380  (Exclude shipping cost)
Weight: Approximately 15kg
Dimension:  W430 X L430 X H85(MM)
Accessories: Stock power cable X1,stock optical cable X1
Not: Since 21th Feb.2011, upgrade to TCXO.
* The ES9018 had higher request of sources than other DAC , it request source have least 0.5Vp-p SPDIF output (Standard is 5Vp-p) and the decent SPDIF waves ,otherwise it can't guarantee  work well with 192K (coaxial input ) or 96KHz (optical input) , if the SPDIF signal too bad maybe cause the sound drop off.   We practised  it can work well with our DI and hiface at 192KHz , and most users had not problems . 

What's new :
       NFB-7.1 had improved on the output analog stages based on the NFB-7.
               The analog parts applied new design and built in the motherboard instead applied modules install . The result is sound improved , detail but more neutral .
 Summarize: Fully discrete amp without any OPA , couple caps ,non- feedback analog output stage and non-feedback Class A power supplys .
       Uses three R-core transformers (135W total), one 35W R-core supplies power for digital parts, another two 50W R-cores supplies power for analogy parts. The power transformers and rectifiers are carefully shielded from the electric field of the power transformers and rectifiers' frequency transmission. More than 45,000uf audio grade NOVER capacitors are used to ensure ample and smooth power feed. The NOVER capacitors are specially custom order from NOVER (U.K.) according to Audio GD¡¦s requirement. A total of 16 PSU groups are used to purify the power supply. To achieve Silent operation, the control circuit is powered with separate regulator.
       Uses mostly DALE and Vishay resistors,  WIMA ,EVOX capacitors and a lot SOLEN caps. The electrolyte capacitors are custom ordered from NOVER (a UK brand), Sanyo OS caps, and exact-matched transistors. RCA sockets are custom ordered and 24k gold-plated. All transistors are Toshiba and Hitachi.

Sound Characteristics:  Neutral without harsh. Please note before placing the order:
DAC NFB-7.1 has extremely high fidelity; its sound signature is neutral. It can show how good or how bad a recording is.
      If you are looking for a DAC which can always deliver quite warm or tube sound, the NFB-7.1 is maybe not your cup of tea.Maybe the NFB-8 will be better. Click to link NFB-9
      If you use the NFB-7.1 with a low grade amp, you can't experience the performance of NFB-7.1 and maybe waste the money.
 Feedback :
http://www.head-fi.org/forum/thread/519166/audio-gd-nfb-10

http://www.hifizine.com/2011/03/audio-gd-NFB-7.1-dac/
 What's different between Sabre chips
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Device Description Package DNR(DB) THD(DB)
ES9018 Sabre 32 Reference 32bit 8-channel audio DAC 64 LQFP 135(Mono)
129(8 channel)		 -120
ES9016 Sabre 32 Reference 32bit 8-channel audio DAC 48 LQFP 128(Mono)
124(8 channel)		 -110
ES9012 Sabre 32 Reference 32bit Stereo audio DAC 64 LQFP 133(Mono) -120
ES9008 Sabre Reference 8-channel audio DAC 64 LQFP 132(Mono)
128(8 channel)		 -118
ES9006 Sabre Premier 8-channel audio DAC 48 LQFP 120 -102

NFB-7.1

                                   

                                                                                    

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 Why there are a few jumpers in the digital part?
        DAC NFB-7.1 has a few jumpers in the digital part, some customers may believe this is a wrong design. But I definitely say no. The NFB-7.1 is designed to separate the digital ground and the analog ground, some design will used a inductance to connect these two grounds, but I think the inductance has a specific frequency characteristic which is not good for audio equipment. In our design, we applied a 0 ohm jumper to connect these two grounds, even though the jumper has 0 ohm, in the high frequencies it still has impedance to insulate the effects between digital and analog ground.

 NFB-7.1 is the third edition design:
         A lot of customers recommended ES9018 to me one year ago, during this year I made a lot of practice, at Jul. 2009, I finished the first edition and spend lot months to test and audition. At Mar. 2010 , The second edition finished. The regular edition finished at Jul. 2010.
   Click image to enlarge.   

About ACSS:
         ACSS (Audio-gd Current Signal System) is Audio-gd's system for transmitting audio signals in the current domain. This concept, first seen in 1966, we have used for many years, and since 2006, have evolved the technology to include all audio signals in our systems from the digital source to the power amplifier. Since 2005, ACSS comp5nts have become Audio-gd's most popular products.


About NFB?
      NFB mean Non-Feedback .
       The NFB-7.1 applies the newest ESS high-end Sabre32 DA chip ES9018 which can support up to 32Bit/96KHz input . Compared to other ES9018 designs, Our NFB-7.1 applies Non-feedback ACSS output stage for I/V conversion, and Non-feedback power supply for the whole gear.
       The ACSS is a non-feedback technology made with discrete amplifiers. Most people know the global feedback design can offer better specs in test measurements, and non-feedback can't do well in test measurements but can offer better sound for the human's ears. Here is a conflict of the classic circuits. But the ACSS opens a new field, it can offer a least coloration sound which is more neutral with very low distortion and high linearity. So it can retain the dynamics, detail and neutral sound but not sound bright or harsh.
       The output buffers are Non-feedback, for low impedance, we applied a two-stage parallel connection, the output impedance is only 20 ohms.
  Click image to enlarge.   

        

       NFB-7.1 applies the excellent DA chip ES9018 and excellent analog output stages, but these are not the only keys of the best sound. The power supply is most important. Even applying the best DA chip and the best amp, if matched to a normal power supply, the total sound may still be average or sound musical, but can't be neutral and detailed. That is why it is easy to find hi-end grade gears maybe without the best chips or amp stages, but with plenteous dedicated DC supply circuits.
       The NFB-7.1 uses 15 groups of high-quality class A parallel connection PSU with dedicated DC supply double-stage PSU, which can offer very clear DC power for the DAC, producing a very black background and neutral sound characteristic. The double-stage PSU is very important for digital parts. Some designs may have very low jitter in theory, but if the power is supplied by a dirty or low-speed power supply, it will increase the jitter and pollute the data, and degrade the sound quality obviously.
      The class A parallel connection PSU has very high input impedance to avoid pulse through the PSU from affecting the DAC and low output impedance with very fast speed and high linearity, so it is a very clean power supply. In my experience, its sound is better than battery power supply, better human sound and neutral.

                 

       

      The NFB-7.1 Digital & Analog / Left & Right Completely Separated Internal Layout, from power transformer and rectifiers etc, the radiating interferences are carefully shielded. And applied fully mono design can reduce the channels cross ,  which can reproduce a wider and deeper sound stage.
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If I only use the RCA output, is the NFB-7.1 wasted or not fully utilized?

            The NFB-7.1 is a real balanced output DAC, it has XLR (balanced), RCA (single-ended), and ACSS output. There are 4 ACSS modules in the NFB-7.1 for balanced output, and all the ACSS modules have balanced input, so even through RCA output, the ES9018 DA chip will perform fully.
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NFB-7.1 Specs

mprovement may result in changes in specifications and
design without notice.

RCA Output
S/N Ratio:>119db
Output Level:2.56V

Frequency Breadth:20-20KHz



XLR Output
S/N Ratio:>122db
Output Level:5.12V
Frequency Breadth:20-20KHz

ACSS Output
S/N Ratio:>127db
Output:2.0MA

Frequency Breadth:20-20KHz


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