4-12-2014

Audio-GD NFB-1 (2015) review
by Maarten van Druten


 

Currently there is a lot of hype on the internet about high resolution audio and asynchronous DAC's.
These DAC's are very popular because they can boost the quality level of your current audio equipment
that's if you buy the right DAC.

But there is not such a thing as the best DAC.
Why? because everybody hears differently, and it's is also a matter of taste.
What my friends like doesn't have to be my preferred choice.
Some people like a hyper analytic soundscape, others prefer a more smooth, "warm" sound,
while others like a neutral as possible sound. of maybe something in between.

A DAC can have a great influence on how your set will finally sound, it can make your set sound more vivid,
or for example it can also polish the sharp edges of your current system.
therefore always listen very carefully and let "your own taste" decide.

A new DAC has always to be heard in combination with your amplifier en loudspeakers.
Together they make the final sound.

There a many manufactures of DAC chips.
Popular ones are TI-Burr Brown, Analog Devices, ESS Sabre and Cirrus Logic-Wolfson.
Each of them are good brands, but they all have their own character.
To make the choice even more difficult the same DAC chip can sound completely different in Brand A
then in Brand B.

Why? because the technology that is being used around the DAC differs from company to company.
for example the Audio-GD NFB-1 (2015) DAC uses a ESS Sabre 9018 Reference chip, which is also used by other high-end brands like dCS.


The Audio-GD DAC NFB-1 (2015) is beautifully built, by hand with High-End grade parts like DALE resistors, WIMA caps.



dCS is a company that makes very nice sounding DAC's. their DAC's are highly recommended.
I have heard their DAC's on several High-End shows, and they sound very clean, neutral with a lot of control.

What they don't tell is that they also use at the base the ESS DAC chip set, and around this they put a lot
of technology of themselves. they called it: dCS Ring DACô
But for me their products are too expensive. I have to admit, I can't afford them.
Their newest DAC Vivaldi costs $34,999 and that's a lot of money.

Audio-GD NFB-1 also uses the ESS 9018 chipset as the base of their DAC which supports DSD, DXD and PCM.
This DAC is balanced and uses a very interesting technique called "ACSS"

 

Audio-GD Current Signal System  "ACSS"

To make a very technical explanation simple, ACSS (like Krell "CAST" technology) shortens the signal path.
Audio-GD believes that the shortest path is the best one, and this technique sounds the most neutral.
To make full use of this ACSS system you also need a compatible amplifier that supports ACSS.
Audio-GD say that Krell "Cast" amplifiers are also compatible with Audio-GD's "ACSS" system.
I have an Audio-GD "Master-10" amplifier myself, which also has ACSS inputs.

Neutral also means that you have to be careful what you will "feed the dac"
bad recorded music, will also sound bad, and good recorded music will sound good.
The dac will just translate what you will give to him.


Two ACSS cables are connected to the NFB-1 DAC (one for each channel)


...on the other side are the ACSS cables connected to the balanced ACSS inputs on the Master-10 amplifier.
 

The NFB-1 (2015) DAC has a simple but functional display
The first letter indicates what mode the DAC uses. P for PCM only mode or d for combined "PCM/DSD" mode.
The second letter indicates what music file is played P for PCM encoded material, d for DSD material (like: DFF or DSF files)
the last digit indicates which input has been selected, in this case 1 (USB asynchronous) has been chosen.






The Audio-GD NFB-1 DAC & Audio-GD Master-10 amplifier connected together with ACSS balanced cables.

 

NFB-1 inputs and outputs

The NFB-1 has 4 different inputs.
You can choose from:
IN1 - USB (asynchronous)
IN2 - i2s
IN3 - S/PDIF optical digital
IN4 - S/PDIF coaxial digital




The NFB-1 has also multiple outputs:

The NFB1 has balanced outputs XLR, RCA and ACSS


I2S - "Integrated Interchip Sound"

The best way to connect this DAC to your computer or transport is i2s.

"i2s" is not new, but is new for many of us, it's a Philips/Sony invention from 1986 called "Integrated Interchip Sound"
and it's a interface standard for connecting digital devices together.
Specially for PCM encoded material.
The best part of this interface system is that it separates the clock and serial data from each other.
Which results in a very low jitter.
and it gives also a better sound quality because the data is transported directly to the DAC.
For example If you use USB to connect to the DAC;
the digital signal has first to be encoded to USB protocol then the data will be transported, and at the other side (DAC)
the data has to be de-coded back from USB to the original data again.
This USB encoding en decoding can result in little faults that can cause "jitter".

So "i2s" is the best way to connect your HTPC to your DAC.
There are only two cons, for example a pci-e "i2s" card for your HTPC are rare and expensive,
and "i2s" is meant for PCM encoded material only.
In the future it will maybe possible to transport native DSD encoded material, but now it's limited to PCM only.

Unfortunately I couldn't test i2S for this review because I didn't had a good i2S connection cable.
Later I will write a extended special review about i2S on this website.

The second best way to connect the NFB-1 DAC to your HTPC is USB.
Audio-GD has a special driver for Windows operating systems, that enables USB Asynchronous Transfer Mode.
So that the original specs of the USB bus will be extended to playback DSD64,DSD128,and even DXD support.

For more info look on their website:
http://www.audio-gd.com/Pro/dac/USB32/USB32EN.htm

The big disadvantage of USB Asynchronous Transfer Mode, is that there is no fault control what so ever.
It's like that the protocol says: "I don't care which packets I have to transport on this high-way, I just transport it!"
this can result in little faults that can increase "jitter".

So the USB Asynchronous Transfer Mode differs from "i2s" is this way, for the cleanest sound always choose "i2s"

My music collection contains PCM (75%) and DSD (25%) material.
For this review I tested all possible connection and operating systems.
I have to hear which operating system gives the best sound, and also with which connection.
Unfortunately I didn't had an "i2s" pci-e card during this test so I did all test with USB.
 

Supported operating systems

The NFB-1 preferred Operating system is Windows and Mac OS in combination with the USB or i2s.
Audio-GD also has a special USB driver available for Windows, Mac OS doesnít need a special USB driver.

Because I use Linux (Ubuntu 14.04 LTS) on my passive cooled i7 HTPC, I also tested this DAC on Linux.
I got the best results by turning on the DAC first and then the HTPC.


Linux (Ubuntu)

Ubuntu 14.04 LTS recognized the Audio-GD NFB-1 DAC automatically as "Digital Output (S/PDIF) Audio-gd" when it's connected with USB.



After selecting this output device, I played some PCM High-Resolution music with the "DeadBeeF" music player.
Which is open source and free and can be downloaded at http://deadbeef.sourceforge.net/.

I was surprised with the nice transparent and neutral sound of this dac.
The DAC gives a lot of details and also plays the music with much ease and control!

It even played DSD material with the "Cantata" music player deamon! which is very good news.
but playing back DSD material (dsf and dff files) is still experimental under Linux.
So it's better to wait a little, and stick for the time being to PCM material in combination with the DeadBeeF music player.

But Iím convinced that Linux will be a very good audiophile platform in the future!
The NFB-1 DAC worked without installing any drivers!


Windows 7 (64bit)

I have a dual boot on my HTPC, so I can choose between Linux and Windows 7.
Audio-GD has made a special USB driver for Asynchronous Transfer Mode which I installed first.
I have turned off "High Definition" audio in the bios of my computer. (which also disables the S/PIF break-out card)
I did this because I didn't wanted that my computer does anything with the digital audio signal.

The computer only has to transport the digital music signal to the dac.
Not to change it, not to compress it, just transport the bits and bytes via USB to the DAC.

The Master-10 intergrated amplifier is a real power house!

 


Together they are a perfect match. they are connected by Audio-GD ACSS balanced connectors
for the shortest signal path possible.



First install the special USB drivers that can be found on the Audio-GD website
before connecting the NFB-1 DAC to your HTPC.
Always turn off the power before you change a connection cable!

In Windows, you can choose which audio device you want to connect to your DAC.


I wanted to use "audio-gd USB audio"device, so I disabled all other
audio devices.


Foobar2000

On Windows there are several good audio players for playing back
high-resolution audio, but one of the best (and free!) it's called "Foobar2000"
It can be downloaded here:
http://www.foobar2000.org/

The best part of this program is that you can install optional "components"
like the DSDIFF Decoder 1.4.
This encoder makes it possible to playback DSF and DFF files!
Also Foobar2000 is very popular because of this, and it sounds very good!
To accomplish this you have to make some adjustments in the program.
So a little advanced computer knowledge is needed.


"Foobar2000" playing DSD files (dsf) from "Michael Jackson's album - Thriller"
 

I have listened to several music from Fusion Jazz to Dance FLAC files.
The Audio-GD NFB-1 DAC has a very neutral but precise character, it renders every musical instrument with a lot of "air"
around it. it has also a deep but tight bass and gives a lot of details.

When playing 44.1 kHz FLAC files of artist "Melody Gardot - The Absence" the NFB-1 proves to be also a musical performer.
The music is rendered very enthusiastic and lively.
The voice of Melody Gardot is very warm, and full of emotion. the NFB-1 also has a very good spatially sound stage.
every instrument is presented fully separated in the living room.
if you close your eyes you can almost "see" the musicians in front of you.

You don't need high-resolution music files to enjoy this dac, it has a lot of resolution form it self :-)
The quality of the music on Windows with Foobar2000 was great and sounded very good.
Maybe a little better than on the Linux platform but the differences were very minimal, I thought that on Windows
I could hear that the music was a little bit more brighter than on Linux.
But the differences were very minimal.


Mac OSX

I also tested the NFB-1 DAC in combination with Mac OSX 10.8.5
I have a MacBook Pro Retina, Mid 2012 (i7 with 8 Gb memory)
Model Identifier: MacBook Pro 10.1
I connected the MacBook Pro with USB to the Audio-GD NFB-1
to get the best results.
(I didn't choose the 3.5mm optical S/PDIF cable because this cable is limited to 96 kHz)
Mac OSX doesn't need a special USB driver for Asynchronous Transfer Mode,
like Linux it just works straight out of the box!


 

Audirvana Plus

Like many other high-resolution players "Audirvana Plus" is still in beta phase.
A lot of users complain in forums about crashes, reboots, and that the program doesn't want to start...
During the months I bought the program, I got many updates and the program is still
not reliable enough to playback DSD files flawlessly.

Keep this in mind when you buy this program, all techniques spoken in this review "DSD, i2s, DXD"
are very new, and a lot of progress has to be made to let it make work flawlessly.
Audirvana is currently still one of the best High Resolution music players for the Mac
so I still bought it to experiment with it.
Audirvana has some interesting options like: "Direct mode" and "Integer mode"
 

Direct Mode

In this mode Audirvana Plus bypasses completely CoreAudio, including its low level layers.
This enables a further shorter audio signal path for better sound quality,
and gives possibility to enable Integer Mode in Lion (10.7) and later.
Version 10.7: "Lion"
Version 10.8: "Mountain Lion"
Version 10.9: "Mavericks"
Version 10.10: "Yosemite"
I have "Mountain Lion" 10.8 which is a good version for High Resolution Audio because, it
combines stability with speed and it's "lighter" for the CPU than the newer Mavericks and Yosemite.
 

Integer mode

In this mode Audirvana Plus will directly sends the audio data to the lowest level in CoreAudio, bypassing the driver audio mixer and the format converter. This enables to a achieve very high sound quality.
There are two different streaming modes in Integer Mode:
Mode 1 that brings the highest transparency, and sound stage depth
Mode 2 that is more on the warm side.

Source: Audirvana User Manual page 28 (
http://audirvana.com/delivery/Audirvana%20Plus%20User%20Manual.pdf)

So the best way is to turn "direct mode" and "integer mode" on for best results.

During start up the Audio-GD DAC gets recognized as "audio-gd USB audio" in Audirvana Plus.
"integer mode" is the best mode, because only then you will have native DSD64 and DSD128 playback,
that's if you dac supports DSD and that your dac is supported by Audirvana.

When you put the NFB-1 DAC is in "Automatic Detection" with Integer mode turned "on" the NFB-1
gives the following results (see picture below)


no DSD support, only PCM support (with DXD 384kHz)

 

When I selected "Initial dCS method", all available frequencies became
available but I didn't got any sound out of the NFB-1 DAC...




When "DSD over PCM standard 1.0" is selected, all available frequencies
are available (and become green)

And all DSD files were playable. (DSF and DFF) and the display of the NFB-1 showed: "dd1"



For me this is the best option to listen to the Audio-GD NFB-1 DAC.
I played the DSF files taken from the SACD: "Stan Getz
and Joao Gilberto: Getz/Gilberto"
with the song
"The Girl from Ipanema".
The music was very lively and clear, the dynamics were very high.

I played several other DSD files and they all sounded very good on the NFB-1, the music sounds very 3-D like, neutral and detailed. with a very good sound stage.
Also the bass is very tight and deep.

What is the best operating system for the Audio-GD NFB-1 DAC?
That's difficult to tell, MacOSX with Audirvana sounded very good, maybe a little bit more warmer and softer than on Windows with Foobar2000.
On Linux the NFB-1 DAC also sounded very good, but DSD support is still experimental on Ubuntu, so I think it's better
to wait a little longer before switching to Linux for High-Resolution DSD playback.

PCM playback on Linux is fully supported and sounded very stable and good.
So to give a good answer on this question, it also depends how your music library looks like.
If you have more PCM music files than Linux, MacOSX and Windows are excellent choices.

If you have also a lot of DSD music files (DSF and DFF) then the current choice is limited to Windows and MacOSX.
I think that DSD on Windows with Foobar sound a bit more detailed and clearer than on MacOSX with Audirvana.
But what I explained before is all a matter of taste, and it also depends on the quality of the recording.

 

Conclusion

The Audio-GD NFB-1 is a very good DAC, to tell the truth it's the best DAC that I yet have heard.
I compared the NFB-1 with another DAC: the M1 DAC from Musical Fidelity.

The Musical Fidelity M1 DAC next to Master-10 amplifier, unfortunately the M1 DAC is no match for the Audio-GD NFB-1...


The M1 DAC uses the Burr-Brown DSD1796 D/A chip which is also high appreciated in the High-End community.
But compared with the NFB-1, the Musical Fidelity M1 DAC sounds softer, warmer but also flatter.
The NFB-1 has more energy, has more details, and is more neutral and analytical.

The Audio-GD NFB-1 has a better 3D sound stage than the Musical Fidelity M1 DAC.
After this review I sold my M1 DAC, because I liked the sound character of the NFB-1 better.

Like the dCS DAC's I have heard, the Audio-GD NFB-1 DAC also gives the listener a feeling
that everything is under control.
This is a sign that the DAC is very good, and that is really remarkable considering the price point of this DAC!

One other aspect of the NFB-1 is it's versatility.
It can play PCM (24bit 192 kHz), all DSD64 and DSD128 formats (DSF and DFF) and also DXD (384 kHz!) files.
This makes the NFB-1 DAC a very modular DAC, it will almost play anything for you.

Also the ACSS connection is a big advantage, because of this excellent connection system the sound
is very clear, detailed and 3D like. I never heard this before with any other DAC's I have heard.
compared to the NFB-1 they sound duller, flatter and have less dynamics.

Are there no cons?
Yes of course no DAC is perfect, and also the NFB-1 has some little cons.
For example when you switch in Foobar from a PCM audio file to a DSD music file, you can hear some "plop's"
on the speakers. for me this is not a problem because the DAC is changing to a different mode.
I want the best possible sound quality, that is all what matters for me.

I highly recommend this DAC, make sure it's on your wish list when you want to buy a new High-Resolution DAC!
For this money I think it's a very good buy.

Well done, Audio-GD!



Maarten van Druten - "Audio Dandy"
07-12-2014





Special thanks to Rob & Jos from Magna Hifi for
excellent support and service!


http://www.magnahifi.com/

 



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