[SodaBoy]

Three new amps available for preorder from Audio-GD, release in June 15th, 2015.
 
C-2 (11th Anniversary Edition)  USD480 http://www.audio-gd.com/Pro/Headphoneamp/C22015/C22015EN.htm
NFB-1AMP                               USD520 http://www.audio-gd.com/Pro/Headphoneamp/NFB1AMP/NFB1AMPEN.htm
NFB-3AMP                               USD230 http://www.audio-gd.com/Pro/Headphoneamp/NFB3AMP/NFB3AMPEN.htm    
 
The C-2 and the NFB-1AMP are new Class A amps based on the Master 9 design. The C-2 is single ended, while the NFB-1AMP is fully balanced. The NFB-3AMP is a new lower price single ended Class A amp.
 

 Different to the C-2 ( 11th Anniversary Edition ):
 
The C-2 is a single ended  headamp and preamp (+/- 30V DC high voltage power supply ), The NFB-1AMP is balance  headamp and preamp (+/-15V DC power supply ).  So They had same output power specs can drive most headphone as well.
If customer like to keep your headphone with single ended connector (6.3MM), choice the C-2 get better performance than the NFB-1AMP.
If customer had the balance connector headphone or can modify the headphone with balance connector, choice the NFB-1AMP.

 
External Photos
 
Both the C-2 and the NFB-1AMP share the same case, depicted below:
 

 
 
And the NFB-3AMP
 

 
 
Internal Photos
 
NFB-1AMP Internals
 



C-2 Internals
 

 
 
NFB-3AMP Internals

 
 

 

[session76]

which would you recommend for a Hifiman he6?

 

[SodaBoy]

which would you recommend for a Hifiman he6?

 
I recommend the NFB-1AMP, it has 8000mw into a 40 ohm load and should be able to handle the HE-6 (50 ohm) comfortably. Keep in mind that the NFB-1AMP is balanced, you will need a balanced cable for the HE-6.
 
EDIT: Corrected by Kingwa, former observations based on an incomplete spec sheet. Both the C-2 and NFB-1AMP should drive HE-6 comfortably.

 

[gto88]

So, the new NFB-1AMP is replacing NFB-6, and its power spec is very similar as power amp part of NFB-28.
Its web. says its discounted for pre-order, but not saying how much, any idea?

 

[SodaBoy]

  So, the new NFB-1AMP is replacing NFB-6, and its power spec is very similar as power amp part of NFB-28.
Its web. says its discounted for pre-order, but not saying how much, any idea?

I have no idea haha, I'm not an insider really so dunno how much preorders are saving.
 
But yeah the NFB-1AMP is replacing the old NFB-6 and there are a few changes/improvements.
 
SNR 125dB vs 120dB (5dB improvement)
100 steps volume control vs the old 80 steps
New NFB-1AMP only has one gain setting (+16dB), old NFB-6 had two gain settings (0dB low gain and 9dB high gain), hard to say if this was an improvement or not (depends)
Exponential Volume Control available on NFB-1AMP which used to be exclusive to the C-2, Master-9, HE-9, Ref 10.32, and NFB-27 (basically the TOTL models)
Lower THD, this is inferred since there was no THD plot on the NFB-6. The THD plot looks impressive as hell.
 
There might be a few things I missed, but basically these are all the things I ever wanted in an amp, for me this is pretty much perfection. Once I get this, I am done with amps (famous last words lol). I'm glad I held out, there was a reason why I didn't go for the Gustard H10 (or the NFB-6) despite already owning the Gustard X12 + U12. The NFB-1AMP is basically a mini-Master 9. I feel that Audio-GD genuinely made the best amp they could for the price, no intentional feature cuts, no gimping the design to force a price structure.
 
IMO, the relay attenuator volume control and excellent channel balance on the Audio-GDs truly distinguish them in the audio realm. This is a feature usually found only on amps USD 1,000+ amps, and even then there are a bunch that are still using ordinary alps blue at that level. By comparison the Violectric V281 relay attenuator upgrade costs $579.95 alone, more than the cost of the whole NFB-1AMP. Crazy value.

 

[Kingwa]

The C2 had improved than the older. The power is much stronger.

Headphone amp Output Power  ( Max  )

25 ohm:   9900MW 40 ohm:   8000MW 100 ohm: 3500MW 300 ohm: 1200MW 600 ohm:   600MW

 

[SodaBoy]

  The C2 had improved than the older. The power is much stronger.

Headphone amp Output Power  ( Max  )

25 ohm:   9900MW 40 ohm:   8000MW 100 ohm: 3500MW 300 ohm: 1200MW 600 ohm:   600MW

Welcome, I didn't expect Kingwa to drop by. In this case C-2 can drive anything out there easily. I assume the specs for the NFB-1AMP are the same? I do not see the headphone amp max output power within Class A for the NFB-1AMP. I think the spec sheets have been updated since I last saw it, the THD plot on the NFB-1AMP is now correct and not only matches the Master 9 but even exceeds it at certain points.

 

[Kingwa]

Their distortion most on the  2nd Even Order Harmonic Distortion , the  larger distortion or small can not make the sound worst , but larger distortion make the sound smoother,the small make the sound more transparency .
Usually high biase current class A had bigger Even Order Harmonic Distortion .

 

[SodaBoy]

True, I believe that's why some prefer the sound of tubes which should add predominantly 2nd order harmonics. It's preferable that odd and higher order distortion and intermodulation distortion be kept as low as possible. Always on, high bias current should remove crossover distortion as well? On another note, the NFB-3AMP looks similar to it's bigger brothers, but without the relay attenuator volume control, and a different PSU. Any comment on that?

 

[Kingwa]

The NFB3AMP had also the class A PSU built in . And 4 pcs 150W big power transistors as the output stages.

 

[cskippy]

I'm curious what the pure class A output is for the NFB-1AMP?

 

[Stillhart]

I know folks have mentioned that the NFB-1AMP is similar to the amp stage of the NFB-28.  If I already have an NFB-28, which I'm currently only using as an amp, is there any reason to get an NFB-1AMP?  Will it be an upgrade?  The only really obvious thing I can see is that is has ACSS inputs to I can use the DAC-19 via ACSS instead of RCA.

 

[TheChillburger]

The 1AMP looks like a good competitor to the Liquid Carbon. I might have to switch my preorder!

 

[Stillhart]

  The 1AMP looks like a good competitor to the Liquid Carbon. I might have to switch my preorder!

 
As I said in the DAC-19 thread, I'm considering cancelling my LC preorder for the NFB-1AMP as well.  I'm curious if it'll be much of an upgrade from my NFB-28 tho.

 

[cskippy]

I think the biggest difference is that the NFB-1AMP is pure class A at least for the first watts.  That should be enough power to stay in class A for pretty much all headphones at normal to high listening levels.  The other benefit is that the power supply is just for the amp and not shared between amp/dac like the NFB-28.