[ninjikiran]

First off, Thumbs up on the power supply description.  Audio-Gd should put that on their site
Quote:

I am in the same situation as you. I am considering all Audio-GD DAC models below USD 1000 (NFB-1WM, NFB-10WM, NFB-2/NFB-3) built with dual WM8741 DAC and WM8805 receiver to replace existing StageDAC (dual WM8741 / WM8804 receiver). I suppose Audio GD's output stage built with discrete components produces more neutral and natural sound signature than those built with op-amp integrated circuits (designer has perfect control of electrical parameters of the output stage).
 
My considerations are based on some rationales as follows:

 

 

[Kingwa]

Just update the FAQ
http://www.audio-gd.com/Agents.htm

 

[ninjikiran]

awesome now get my NFB-2 out before the 28th! jk.  I ordered some time earlier this week  so  I think I am in a later batch.
 
Quote:

Just update the FAQ
http://www.audio-gd.com/Agents.htm

 

[littletree76]

 
Quote:

Just update the FAQ
http://www.audio-gd.com/Agents.htm

Kingwa thank you for your prompt response. Tabulation of power supplies I have made (prone to error and sorry for misleading information) is entirely based on product descriptions in Audio-GD website and I never realized there are two type of discrete power supply units (Class A and Linear) beside off-the-self 3-pin linear regulator integrated circuit. Basically discrete linear power supply share the same circuit design as 3-pin linear power supply except it is implemented with discrete components for tighter tolerance and better quality. I suppose it is safe to assume following quality assessment:
Discrete Class A > Discrete Linear > 3-pin Linear
 
Power supply units for NFB-2 is surprisingly better than NFB-10WM (space and price constraints because of headphone outputs). If you want ultimate power supply implementation, it is worthwhile to pay more for NFB-2 than settle for cheaper NFB-3. NFB-2 and NFB-1WM share the same dual FET buffer output stage connected directly to output of ACSS module whereas NFB-10WM has Diamond buffer output stage connected directly to output of ACSS module.
 
So to have DAC under USD 1000, the choice for me is between NFB-1WM (balanced/unbalanced) and NFB-2 (unbalanced only), and NFB-10WM (balanced/unbalanced) if I really need all-in-one solution with headphone/pre-amp outputs.
 

 

[Kingwa]

In my mind , it is correct .
Discrete Class A > Discrete Linear > 3-pin Linear
The disctete linear is simple configuration than 3 pin linear, I think simple configuration is better for sound.
But in headphone amp , we applied discrete linear, it allow large power output than the class A PSU and less heat.

 

[HT cOz]

 
Quote:

Just update the FAQ
http://www.audio-gd.com/Agents.htm

 Very interesting information.  Does anyone have a feel for the differences those power supplies make?  I'm buying this DAC for use in my system for many years, maybe I should just ponny up $150 and get the NFB-2?  Thoughts?

 

[V3ng3anc3]

Just ordered my NFB-2 with C-2 amp. Hopefully I will not feel the need to upgrade in a looonnng time.

 

[vrln]

Quote:

 
Quote:

Just update the FAQ
http://www.audio-gd.com/Agents.htm

 Very interesting information.  Does anyone have a feel for the differences those power supplies make?  I'm buying this DAC for use in my system for many years, maybe I should just ponny up $150 and get the NFB-2?  Thoughts?

The power supply, in addition to the DAC chip, is probably the most important component when it comes to creating good sound quality. If you want to know more technical stuff, google "class A audio amplifier". Class-A is considered the best sounding. In practise as the prices go up, the power supplies get more comprehensive. As you get a higher level product though, it will be more revealing when it comes to bad recordings and sources.

 

[HeatFan12]

Quote:

Just ordered my NFB-2 with C-2 amp. Hopefully I will not feel the need to upgrade in a looonnng time.

Nice combo Congrats!   

 
Quote:

 Very interesting information.  Does anyone have a feel for the differences those power supplies make?  I'm buying this DAC for use in my system for many years, maybe I should just ponny up $150 and get the NFB-2?  Thoughts?

I believe either choice will fit the bill nicely for you.  If you have the extra 150 beans, I say go for it...Hopefully, that is the case and you won't have to upgrade in a long time.  But you need to get away from this place for that to happen.......lol....
 
Cheers
 

 

[Dinglehoser]

I have an Oritek modded Zhaolu (version 4.1, I believe).  Does anyone with experience with the OMZ DACs know whether either the NFB-2 or NFB-3 would be an upgrade, or at least comparable?

 

[middachten]

I've doubting about which Wolfson based DAC from Audio-GD I would order. The NFB-2/3, the NFB-10 or the NFB-1.
The recent discussion on power supplies and the FAQ on the AGD website has helped a lot! I don't need a symetrical/XLR connection. But I was hoping that the NFB-10 would be a better overall performer considering that it could also replace my current preamp. 
Now I seem to be better of with the NFB-2. It has almost the same power supply topology as the NFB-1 except for the extra transformer. I guess this is an improvement, but the NFB-2 also has two analog stages less to supply!
 
Anyway, I've made my choice: NFB-2.
Now lets wait 1-2 weeks to see if A-GD can get their production / logistics back on track!
 
Thanks for all the input in this thread!

 

[V3ng3anc3]

Quote:

I've doubting about which Wolfson based DAC from Audio-GD I would order. The NFB-2/3, the NFB-10 or the NFB-1.
The recent discussion on power supplies and the FAQ on the AGD website has helped a lot! I don't need a symetrical/XLR connection. But I was hoping that the NFB-10 would be a better overall performer considering that it could also replace my current preamp. 
Now I seem to be better of with the NFB-2. It has almost the same power supply topology as the NFB-1 except for the extra transformer. I guess this is an improvement, but the NFB-2 also has two analog stages less to supply!
 
Anyway, I've made my choice: NFB-2.
Now lets wait 1-2 weeks to see if A-GD can get their production / logistics back on track!
 
Thanks for all the input in this thread!

That's exactly the same conclusion I ended up with, but I got the C-2 as well since I wanted a desktop SS amp/pre-amp.
 

 

[HT cOz]

I too switched my order to the NFB-2.  It put me back to the end of the line... but patience is a virtue.  I figure that the power supplies in the NFB-2 put it very close to any DAC Audio-GD makes.  Naturally that last 5% will cost you in money and complexity, but I may just be happy to live at 95% for a very long time.  I think it will be a while before the NFB-2 is the weak link in my system.  Good thing too, since Audio is a hobby and all of lifes other priorities trump my rig.  lol...  Most of my system was collect while I was in DINK status. 

 

[pautinqch]

So, 3-pin linear is significantly worse (vs. Class A) aurally ? For example NFB-1 against NFB-10.
 
Quote:

 
Quote:

Just update the FAQ
http://www.audio-gd.com/Agents.htm

Kingwa thank you for your prompt response. Tabulation of power supplies I have made (prone to error and sorry for misleading information) is entirely based on product descriptions in Audio-GD website and I never realized there are two type of discrete power supply units (Class A and Linear) beside off-the-self 3-pin linear regulator integrated circuit. Basically discrete linear power supply share the same circuit design as 3-pin linear power supply except it is implemented with discrete components for tighter tolerance and better quality. I suppose it is safe to assume following quality assessment:
Discrete Class A > Discrete Linear > 3-pin Linear
 
Power supply units for NFB-2 is surprisingly better than NFB-10WM (space and price constraints because of headphone outputs). If you want ultimate power supply implementation, it is worthwhile to pay more for NFB-2 than settle for cheaper NFB-3. NFB-2 and NFB-1WM share the same dual FET buffer output stage connected directly to output of ACSS module whereas NFB-10WM has Diamond buffer output stage connected directly to output of ACSS module.
 
So to have DAC under USD 1000, the choice for me is between NFB-1WM (balanced/unbalanced) and NFB-2 (unbalanced only), and NFB-10WM (balanced/unbalanced) if I really need all-in-one solution with headphone/pre-amp outputs.
 

 

[vrln]

This is taken from Wikipedia...
 
 

Advantages of class A amplifiers

1. Class A designs are simpler than other classes; for example class AB and B designs require two devices (push-pull output) to handle both halves of the waveform; class A can use a single device single-ended.
2. The amplifying element is biased so the device is always conducting to some extent, normally implying the quiescent (small-signal) collector current (for transistors; drain current for FETs or anode/plate current for vacuum tubes) is close to the most linear portion of its transconductance curve).
3. Because the device is never shut off completely there is no "turn on" time, little problem with charge storage, and generally better high frequency performance and feedback loop stability (and usually fewer high-order harmonics).
4. The point at which the device comes closest to being cut off is not close to zero signal, so the problem of crossover distortion associated with class AB and B designs is avoided.

[edit]Disadvantage of class A amplifiers

1. They are very inefficient; a theoretical maximum of 50% is obtainable with inductive output coupling and only 25% with capacitive coupling, unless Square law output stages are used. In a power amplifier this not only wastes power and limits battery operation, it may place restrictions on the output devices that can be used (for example: ruling out some audio triodes if modern low-efficiency loudspeakers are to be used), and will increase costs. Inefficiency comes not just from the fact that the device is always conducting to some extent (that happens even with class AB, yet its efficiency can be close to that of class B); it is that the standing current is roughly half the maximum output current (although this can be less with Square law output stage), together with the problem that a large part of the power supply voltage is developed across the output device at low signal levels (as with classes AB and B, but unlike output stages such as class D). If high output powers are needed from a class A circuit, the power waste (and the accompanying heat) will become significant. For every watt delivered to the load, the amplifier itself will, at best, dissipate another watt. For large powers this means very large and expensive power supplies and heat sinking.

Class A designs have largely been superseded by the more efficient designs for power amplifiers, though they remain popular with some hobbyists, mostly for their simplicity. Also, many audiophiles believe that class A gives the best sound quality (for their absence of crossover distortion and reduced odd-harmonic and high-order harmonic distortion) which provides a small market for expensive high fidelity class A amps.

 

(source: http://en.wikipedia.org/wiki/Electronic_amplifier#Advantages_of_class_A_amplifiers)