Audio-GD NFB-12: Does the "DAC Out" bypass the amp section?
Jan 7, 2014 at 1:04 AM Post #2 of 4
The "DAC Out" bypasses the NFB-12's headphone amplifier section.
 
Jan 7, 2014 at 7:41 PM Post #3 of 4
The NFB12 design is total different than classis design.
The ACSS design made the signal journey very short, only one stage analog gain stage for headphone and DAC output. And so the outputs are same source.
 
       The standard current model  design usually need 3 amps (OPA) , the first amp is the difference amp ,  conversion the 4 channels output signal from WM8741, become a single ended signal  .
       The second amp  implement the low pass analog filter , then through  volume control  feed to the third amp, the headphone amp .
       Every amp usually have two gain stages built in so  the WM8741 signal must through total 6 gain stages arrive the output stages .
       The NFB-12 applies Non-feedback ACSS design. The WM8741 feed to the ACSS circuit without any OPAs .
       The ACSS circuit conversion, signal difference and headphone amp in current model in one ACSS amp . And this ACSS amp only have one current gain stage , the WM8741 output signal only through one stage can arrive the output stages .
      The shortest signal journey can reproduce the best detail and dynamic, and almost without sound coloration , It can show the  real performance of the WM8741 .
       So our ACSS design is the best combo with WM8741 achieve the best performance .
 

 
Jan 8, 2014 at 11:05 PM Post #4 of 4
  The NFB12 design is total different than classis design.
The ACSS design made the signal journey very short, only one stage analog gain stage for headphone and DAC output. And so the outputs are same source.
 
       The standard current model  design usually need 3 amps (OPA) , the first amp is the difference amp ,  conversion the 4 channels output signal from WM8741, become a single ended signal  .
       The second amp  implement the low pass analog filter , then through  volume control  feed to the third amp, the headphone amp .
       Every amp usually have two gain stages built in so  the WM8741 signal must through total 6 gain stages arrive the output stages .
       The NFB-12 applies Non-feedback ACSS design. The WM8741 feed to the ACSS circuit without any OPAs .
       The ACSS circuit conversion, signal difference and headphone amp in current model in one ACSS amp . And this ACSS amp only have one current gain stage , the WM8741 output signal only through one stage can arrive the output stages .
      The shortest signal journey can reproduce the best detail and dynamic, and almost without sound coloration , It can show the  real performance of the WM8741 .
       So our ACSS design is the best combo with WM8741 achieve the best performance .
 

Thank you, Kingwa, for this very thorough answer to my question. 
 

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