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NFB-5.32（USB applied USB-32）
Discrete  DAC+ Headphone amplifier / Preamplifier

32bit / 384K Asynchronous Transfer  USB-32 Chip
Built in 2 Pieces Hi-end grade WM8741 Chips

NFB-5.32 Price :USD378

The rule of the power ON /  OFF:
Power On :
     Source power ON ---->    NFB-5 power ON ----> Amp power ON
Power Off:
    Amp power OFF ---->  NFB-5 power OFF   ---> Source power OFF .

Setting the bit and sampling transfer:
      Win 7 :The NFB-5.32 have driver control panel can setting the bit and sampling , we are recommend setting at 32 bit transfer for the best transfer with WM8741(WM8741 can accept 32bit input data) . (Once users setting 32bit in driver control panel, the Windows device audio control panel will appear 32bit option .)
     In Mac OSX have not driver install necessary , so there is have not driver control panel but users can setting in the OSX MIDI option panel .

The NFB-5 functions:

                
　

Front plate:

Volume knob: Control the volume level of the headphone and variable DAC output.

DAC/HP switch:
Select the output modes of the NFB-5.
Display 1 : Headphone output . Bypass the built in OPA, signal transmit by ACSS only.
Display 2 : Headphone output . The built in OPA active , signal transmit through the OPA convert to ACSS .
Display 3 : DAC output .  Bypass the built in OPA, signal transmit by ACSS only. Users can choice the DAC output either variable and fixed.
Display 4 : DAC output . The built in OPA active , signal transmit through the OPA convert to ACSS .Users can choice the DAC output either variable and fixed.

Gain switch:
Select the high/low gain modes of the NFB-5.       Display H : High gain mode at +12DB.     Display L : Low gain mode at 0DB.

Selector switch:
Select the input modes of the NFB-5.    Display U : USB input.     Display C : Coaxial input.    Display O : Optical input.

Rear:
Power socket: For power input.
USB socket: For USB input.
Opt socket: For optical input.
Coax socket: For coaxial input.
DAC out sockets: For dedicated DAC output. (The DAC output level can be chosen between variable and fixed, see below).

Flavor switch:
Select the oversampling and digital filter response of the NFB-5.

 How to set the NFB-5 DAC output between Variable and Fixed line level ?

    The NFB-5 has one group Line out for dedicated DAC output, In default its output level setting is at variable . But owners can set it to can select between variable and fixed or output variable line level only . See the photos, Push into the jumper for Fixed output (DAC output mode only).

 OPA （The owners must not install the OPA wrong)
(For users choice and purchase to replaced the default chip OPA2134, The NFB-5 can bypass the OPA for most neutral sound, so the OPA just for implement different sound flavors.
http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm