The unit applied analog input short design :
          The unit  had design the analog idle input short circuit (  In 5 and In 6) for avoid the disturb between different sources.
         This design also applied in a lot high end brand devices.
          The working theory :  Without the idle input short circuit ,if the input 5 and input 6 had connect two extra DACs,  while users select the either input 5 and input 6 , the another input signal will fire through the circuits and mix  into the using signal, even though this signal is  weak  but still can degrade on the sound quality.
          With the idle input short circuit function : if user select either the input 5 and input 6, the another input signal will short circuit then no any signal fire through circuits , can keep the sound quality had not degrade.
          If you don't want the input short functions, please custom order or open the unit, take off the jumpers on J1 to J3. J1 is for IN6 RCA analog input, J2 and J3 is for IN5 XLR analog input.

Functions : (Normal working state)

    
OUT button  : For select the unit output from headphone sockets or the XLR / RCA sockets.
Setting button   : For go into the setting menu.
INPUT button   : For select the unit input channels.
1: Coaxial RCA input.
2: Digital Optical input.
3：Digital I2S input.
4,  Digital USB input.
5,  Analog XLR input.
6,  Analog RCA input.
Volume knob: For change the volume of the unit.

Functions : (Setting state)
         The DAC can setting the digital process functions on front plate to change the sound flavors, without open the unit .

        

Important warn:
         Before push the "Setting" button, we are advice user turn  low  the amp volume, stop the music track playing .
         Because for the aim to reproduce the best sound quality, the DAC without mute design , change the setting may output circuit switch sound .
         Around 5 seconds after non any button had push, the display stop blink, user can click the music track to playing and  turn up the volume.
Setting buttons:
          For go into the setting menu.
Left INPUT buttons:
          While the display non blink, for select the input sources.
          While the display blink, for the setting digit move one left.

Right INPUT buttons:
          While the display non blink, for select the input sources.
          While the display blink, for setting the digital process functions.

Gain setting:
         The unit has two gain modes, the 12DB on low gain for drive the headphone which has over 95DB sensitivity, and 22DB on high gain cooperate with the strong power ability,  enough to drive the HE6 which has around 85DB sensitivity headphones.If customer want to boost 6-12DB gain, in total 28-34DB gain.
          Push the "Setting" button one time, the one digit display will blink for active the function setting , turn the volume knob high to set the amp work with High gain (The display show Gn-H), turn the volume knob low to set the amp work with Low gain (The display show Gn-L). After set to High gain, the volume number right down side has a LED light . Set to Low gain , that LED dark.
 





Mode setting:
          Push the "Setting" button one time, the one digit display will blink for active the function setting , push the right "INPUT" button can change function . While the display blink, push "Setting" again , the right next one digit display will blink , push the left "INPUT" button the left next one digit display will blink .

PCM (PCM filters options) :
Display 1: Fast roll-off,  Linear.


Display 2: Slow roll-off, Linear.


Display 3: Fast roll-off, Minimum. (Recommend for most neutral sound )


Display 4: Slow roll-off, Minimum


Display 5: Fast roll-off, Apodizing.


Display 6: Fast roll-off, Hybrid.


Display 7: Brickwall filter.


DSD  (DSD fileters options) :
         Display 4: 47KHz .
         Display 5: 50KHz.
         Display 6: 60KHz.
         Display 7: 70KHz.

Mode (Select Output mode of rear ) :
         "P" for select rear output as preamp, with volume control.
         "d" for select rear output as DAC mode, without volume control.
         Please note:
         1,If your external power amp without volume control, you must confirm the D-27 setting on "P" mode before connect with the power amp.
         2,Both modes have not effect the headphone output mode)

Dark (Display auto dark option) :
         Active (1)  the display auto dark, the display will become dark in around 10 seconds after stop operate any buttons . Disable (0) the display auto dark, the display  light always.