Audio GD NFB6 Headphone Amplifier Review
May 10, 2012 at 11:04 AM Thread Starter Post #1 of 28

Frank I

Columnist/Reviewer at Headphone.Guru
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[size=medium][size=large]Audio GD NFB6 Headphone Amplifier[/size][/size]

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[size=medium][size=large][size=medium]Audio Gd has been a favorite manufacturer for headphone fans having developed a reputation of building amplifiers and other products to very high standard at a reasonable price and the NFB6 follows in the same tradition. The NFB6 is built to a price point but it appears to have been designed in the same tradition as all Audio GD products. It has 5 inputs and is fully balanced. It can be used either with a DAC or CD player in either balanced or single ended mode. It can also be used as a standalone preamp. The retail price is $400.00 without the remote control and for $50.00 extra you can have get a remote control. The case is the traditional black heavy duty case Audio GD uses in most of their products. It also has an 80 step volume control which Audio Gd describes on their web page in detail. For the price it would be difficult to find products built like the NFB6 with all the features described.  Audio GD is packed with features unheard of in this price range.[/size][/size][/size]
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[size=medium][size=10pt]Improvement may result in changes in specifications and
design without notice.[/size]
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[size=medium][size=10pt]S/N Ratio[/size]
 
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[size=medium][size=10pt]>120DB [/size][/size]
[size=medium][size=10pt]Gain[/size][/size]
[size=medium][size=10pt]0DB at Low gain, +9DB at High gain[/size][/size]
[size=medium][size=10pt]Frequency Breadth[/size][/size]
[size=medium][size=10pt]20Hz - 20KHz ( <0.15DB )[/size]
[size=10pt]1Hz - 170KHz    ( - 3DB ) [/size]
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[size=medium][size=10pt]Headphone amp Output Power
(Balanced model , only for headphones)
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[size=medium][size=10pt]4500 MW /  50 ohm

 3000 MW  /  100 ohm

1200 MW / 300 ohm

600 MW / 600 ohm
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[size=medium][size=10pt] Preamp Output Level (Max, RMS)[/size][/size]
[size=medium][size=10pt]10V @ RCA
 20V @ XLR
4MA @ ACSS
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[size=medium][size=10pt]Output impedance[/size][/size]
[size=medium][size=10pt]1 ohm @ XLR[/size][/size]

[size=medium][size=10pt]Input impedance[/size]
 
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[size=medium][size=10pt]90K ohm @ XLR
<10 ohm @ ACSS
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[size=medium][size=10pt]Channels cross[/size]
 
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[size=medium][size=10pt]> 120DB[/size][/size]

[size=medium][size=10pt]Channels imbalance[/size]
 
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[size=medium][size=10pt]< 0.05DB[/size][/size]
[size=medium][size=10pt]Power Requirement[/size][/size]
[size=medium][size=10pt]1 Version  100-120V  AC 50/60 Hz
2 Version  220-240V  AC 50/60 Hz
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[size=medium][size=10pt]Power Consumption[/size][/size]
[size=medium][size=10pt]21W idle @240V or 120V[/size][/size]
[size=medium][size=10pt]Package Weight[/size][/size]
[size=medium][size=10pt]Approximately[/size] [size=10pt]5KG[/size][/size]

[size=medium][size=10pt]Dimensions
 
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[size=medium][size=10pt]W240 X L360 X H80 (MM, Fully aluminium )  [/size][/size]
[size=medium][size=10pt]Accessories[/size][/size]
[size=medium][size=10pt]Power cord  X1[/size][/size]
[size=medium][size=10pt]Operating Temperatures[/size][/size]
[size=medium][size=10pt]+5 °C to +40 °C[/size][/size]
[size=medium][size=10pt]Operating Humidity[/size][/size]
[size=medium][size=10pt]5 % to 90 % (without dew)[/size][/size]
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[size=medium][size=medium]Kingwa sent me this review sample with the remote control. It was burned in for 100 hrs and he said it required at least 300-400 hours to perform its best.  My equipment used for this review was the Oppo BDP95, SA8004 as the source and headphones were the hE500, HD800 AKG 550 and others briefly. I used all the equipment both single ended and balanced, when I received the NFB6 it was hard and edgy right out of the box. I noticed fatigue set in pretty quickly so I continued to burn it in for another 300 hours which it became evident that the unit was changing from both hard and grainy to more of a clean and accurate neutral amplifier.  Kingwa described the sound of this amplifier to me as a wire with gain. I am not one who buy into the idea of any product not having a sound of its own., The wire with gain is a term Quad used many years ago and manufactures all try to say that their product is just a wire with gain,. In my experience all amplifiers I have used in the past 35 years in this hobby all have a sound and are all different in many ways. The NFB6 does have a sound that many will like and some will not. In balanced mode it has a clean and neutral tone but there is no denying this is a solid state unit.[/size][/size]
[size=medium][size=medium]The NFB6 has two gain modes designed into the unit. The low setting is set at 0 db  and high has gain of  9db and my auditioning was done primarily using the low setting as I found the high setting very hard and aggressive and edgy to a point where I always wanted to stop listening. Single ended mode which most users in this price range would be using the amplifier is hard and grainy most of the time with a single ended source and is better in all ways and a significant step up in balanced mode. Single ended most $250.00 amplifiers and many even less priced would be a better option.  The full description of all the power ratings are listed on the website and power for any headphone will not be an issue. The unit is fully discrete design with no opamps and all quality parts. I had to keep reminding myself to review this amp I also had to consider its price point and that all my other headphone amplifiers are two or three times more expensive than the NFB6[/size][/size]
[size=medium][size=medium]The NFB6 sounds better in balanced mode. It drives the HD800 and the HE500 very easily. It is clean and neutral. It had pretty much all balanced flavor to the bass and midrange. The treble at first was brittle but it did get better used balanced and with some hours on the unit.  Most of my time using the NFB6 has been with the HD800 using a Norse balanced cable provided by Trevor for this review. The cable is outstanding and really provided a clear window into the music and allowed me to evaluate this amplifier and hear both the amplifiers strength and also to hear what the amplifier did not do as well.   I have also struggled to write this review as my time with the NFB6 has been a mixed bag of ups and downs.  I think most users using this amplifier would be using the orthodynamic headphones offered by HiFiman and for those headphones this would be a nice low cost alternative [/size][/size]
 

[size=medium][size=large]SOUND[/size][/size]

 
[size=medium][size=medium]The NFB6 in balanced mode is clean. It is also very neutral.  Soundstage is excellent. It is both deep and wide. There is no noise as the amplifier is very quiet. Bass is not tipped. It goes deep but does not hit hard. Treble is as it should be balanced and is brittle single ended. The amplifier is not as dynamic as others I have heard in this price range and some priced less.  High gain makes it hard and aggressive low gain requires the amplifier to be listened to at higher volume settings but it also the best way I found to use the NFB6. Single ended was and is too hard and edgy. Most of all it is very fatiguing and balanced is really where this amplifier is best suited to play music. The NFB6 does not favor any genre all are played equally. Vocals are clean and not sibilant. Instrument tone is good. [/size][/size]
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[size=medium][size=large]CONCLUSION[/size][/size]

 
[size=medium][size=medium]As most can see this has been a very difficult review for me to do.  The NFB6 has been a very mixed bag over the last four weeks. It is a $400.00 amplifier built well and loaded with features. It also need to be used balanced which for many will make this a harder choice as headphone and sources can get expensive. In single ended mode this amplifier is outclassed by lower priced amps. In this price range there are not too many balanced amplifiers. I would only recommend this amplifier for balanced use and in that context it is a three star performer. It is good solid well built amplifier by a manufacturer known for building battleship products. I can see this being used by people as a stop gap owning expensive headphones that want to experience balanced but cannot yet afford a reference amplifier.  It does not excite as the much more expensive amps I have.   It is also not the last word in detail or extension.  I also recommend this for the users of the HE500 as it has gobs of power and it can be used to power the orthodynamic headphones easily. To sum it all up it’s a very clean and quiet headphone amplifier that will please many and can be a good stepping stone for people who want to build a balanced system and to be used as a stepping stone for the HD800 until you  funds for the more expensive audio gd balanced amps or other amplifiers on the market. A good value based on price and recommended only for balanced use.[/size][/size]
 

[size=medium][size=large]DISCLAIMER[/size][/size]

 
[size=medium][size=medium]The NFB6 used was a review sample provided by Audio GD. This is only my impression and others may agree or disagree with my assessment. Everyone has different systems and equipment. As always I ask you to use this impression as a starting point and listen in your system with your own gear. There is no return policy offered by audio gd. The NFB6 offers price value and good build performance and I do recommend the unit.[/size][/size]
 
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May 10, 2012 at 2:59 PM Post #4 of 28
Nice review Frank! This is an important price point for there to be reviews on.  I don't review much inexpensive gear anymore, but I get asked about it a LOT.  So good for you for taking the time to do it.
 
May 11, 2012 at 9:56 PM Post #6 of 28
Interesting review Frank. There's a distinct lack of flowery prose that speaks volumes about the conflicted view you may have a had about this component. It conjures memories of my time with the NFB-10SE - a bang for buck component brimming with features but ultimately unsatisfactory in the way it presents music. It's hard to reconcile great value with equipment that fails the most fundamental tests of enjoyment and musicality.
 
May 12, 2012 at 12:32 AM Post #7 of 28
Quote:
Interesting review Frank. There's a distinct lack of flowery prose that speaks volumes about the conflicted view you may have a had about this component. It conjures memories of my time with the NFB-10SE - a bang for buck component brimming with features but ultimately unsatisfactory in the way it presents music. It's hard to reconcile great value with equipment that fails the most fundamental tests of enjoyment and musicality.

exactly how i felt about the nfb-10se, andd thats why im not even considering the nfb6. on the other hand the c2-SA that i picked upin the classifieds here sounds awesome with my lcd2s and nfb3.1
 
May 12, 2012 at 7:54 AM Post #8 of 28
Quote:
Interesting review Frank. There's a distinct lack of flowery prose that speaks volumes about the conflicted view you may have a had about this component. It conjures memories of my time with the NFB-10SE - a bang for buck component brimming with features but ultimately unsatisfactory in the way it presents music. It's hard to reconcile great value with equipment that fails the most fundamental tests of enjoyment and musicality.

Thansk. I had read some pf the reviews on the NFB-10SE and I was hoping for more with this unit.
 
May 12, 2012 at 7:58 AM Post #9 of 28
Quote:
exactly how i felt about the nfb-10se, andd thats why im not even considering the nfb6. on the other hand the c2-SA that i picked upin the classifieds here sounds awesome with my lcd2s and nfb3.1

Darren I had asked for the 2.2 but Kingwa told me it was going to be replaced and this is the replacement.  Glad y0u like the 2-SA Build quality on audio gd products is excellent.
 
May 15, 2012 at 7:38 PM Post #10 of 28
Well done review Frank! Definitely some limitations involved when selling an amp with this many features at the $400 price. Apparently that played out in your listening. Still, balanced amps on the cheap are not easy to come by, so it's nice to see an option on the market - even if not a perfect one.
 
May 15, 2012 at 7:44 PM Post #11 of 28
Quote:
Well done review Frank! Definitely some limitations involved when selling an amp with this many features at the $400 price. Apparently that played out in your listening. Still, balanced amps on the cheap are not easy to come by, so it's nice to see an option on the market - even if not a perfect one.


it  can be an option for people with a limited budget it is built well and thanks John for the kind words.
 
May 21, 2012 at 3:16 AM Post #12 of 28
hey Frank, thanks for the nice review!
 
I've got my NFB6 and NFB17 combo for a week now and have been enjoying it a lot.
The NFB6 is definately a large step up from my Schiit Asgard, even using the 1/4 unbalanced output.
 
My Denon D7000 (unbalanced) really enjoyed the upgrade, and that considering it is a very easy to drive headphone.
Also, it drives my He500 much fuller than the Asgard (balanced out on the nfb, though).
 
Even though I haven't tried the Lyr+Bifrost combo, that's probably the closest competitor in terms of price, I feel I've significnatly improved my set.
Details are much more present, mids are forward and more embodied (especially on the HE500) and bass hits harder.
 
Jun 7, 2012 at 10:32 PM Post #14 of 28
Quote:
exactly how i felt about the nfb-10se, andd thats why im not even considering the nfb6. on the other hand the c2-SA that i picked upin the classifieds here sounds awesome with my lcd2s and nfb3.1

 
Yep-that was my old C-2 SA and is still the best sounding SS amp I've heard to date along with the C-2. I've owned in the past. I just wish I had a chance to hear them both with my new HD800s as I feel they would make an excellent pairing of 2 different flavors.
 
Also: Nie, honest review Frank. Hope you someday get a chance to hear the stellar amps mentioned here which would probably be a big step in sound quality over the NFB6, single-ended at least.
 
-Daniel
 
Jun 8, 2012 at 11:30 AM Post #15 of 28
Quote:
 
Yep-that was my old C-2 SA and is still the best sounding SS amp I've heard to date along with the C-2. I've owned in the past. I just wish I had a chance to hear them both with my new HD800s as I feel they would make an excellent pairing of 2 different flavors.
 
Also: Nie, honest review Frank. Hope you someday get a chance to hear the stellar amps mentioned here which would probably be a big step in sound quality over the NFB6, single-ended at least.
 
-Daniel


 thanks Daniel the NFB6  is getting time using it balanced
 

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