The unit applied input short design :
Nowdays a lot high and middle range preamps, headphone amps and integrated amps had applied the input short design .
Without the input short design , if the amp connect to multi-ply sources and all source had playing , different sources will had the signal crossing cause the sound quality degrade .
For example, the input 1 connect to a DAC and the input 2 connect to a CDP, while both had playing, the CDP signal will crossing to the input 1 , mix with the DAC signal cause the sound degrade.
In world there are more than 99% DACs and the sources had allow the outputs short , if your DAC decalre can't short the output , please custom order the amp without input short , but in the case , while you connect multi-ply sources, you are better only let one power on and others power off for avoid the signal crossing .

How to connect the Precision 1 ACSS input ?
       The Precision 1 ACSS input can connect any balanced  DACs which is have ACSS design .
       The Precision 1 also can connect the KRELL CAST output devices and STARI source with adapt cables .
       The unbalanced DAC made by audio-gd, like DAC-19, NFB-2 series and NFb-3 series DAC shipping before 15th Aug. 2013, must buy the especial ACSS cable connect to Precision 1 .
       All audio-gd DACs shipping after 15th Aug. 2013 can connect to Precision 1 with standard ACSS cable.
       The Precision 1 RCA inputs can connect any RCA output devices in world .

Full functions protect:
       The Precision 1 have built in MCU to implement protect detect for protect the speakers and the amp have not shatter by wrong operate , the protect detect include separate Left and Right channels DC offset and over current output .
      In normal working state the display won't show the " P - - P" .
      The display flash the "P - - -" mean the Left channel have higher DC offset or over current output .
      The display flash the " - - - P" mean the Right channel have higher DC offset or over current output .
      The display flash the " P - - P" mean the both channels have higher DC offset or over current output.
      In the case, users must shut down the Precision 1, find what matter cause the problems , then power on the Precision 1 again .
      Usually if the source have quite high DC offset feed to Precision 1 may cause the Precision 1 have high DC offset . (Precision 1 built in DC serve can correct low level DC offset of the sources )
      Over current output may cause by below issues:
      A, The speakers cables have short between + and - .
      B, The speakers have not use with long term, the speakers cores have wet cause the impedance is very low .

Keep the Precision 1 have good air follow state.
       The Precision 1  for have larger power output and working safe , it had applied the full chassis as heat sink,  so don't cover other things on the chassis .

Remote control function:
　

Ang1 to Ang4:
Select the output source.
The left 2nd digital display 1 : ACSS input.
The left 2nd digital display 2: RCA input.
The left 2nd digital display 3 : RCA input.
The left 2nd digital display 4 : RCA input.

Vol+ and Vol- : Push once to adjust volume up and down in single step.

H/P: Select the output modes

GAIN: Select the high / low volume mode.
The left 1st digital display 1:   Speaker output with high volume mode. ( For normal sensitivity speakers  ). 
The left 1st digital display 2:   Speaker output with low volume mode . (  For high sensitivity speakers listen by low volume). 
The left 1st digital display 3:  Headphone output with low volume mode . ( For normal sensitivity headphones ). 
The left 1st digital display 4:  Headphone output with high volume mode . ( For low sensitivity headphones , low output level sources ).    

Please note :
A , The Precision 1 have large power output, so for most headphone just need working on low volume mode . 
B , Only for some low sensitivity headphone or connect with the devices which have very low output level can choice the high volume mode .
C , Select the volume modes from low mode to high mode, the volume will reset to 0 for avoid the output power increase a lot.

Front view:    

Power button:
          To power ON/Off the Precision 1.

Setting button:  Select the output modes
        
Gain button: Select the high / low volume mode.

 The left 1st digital display 1:   Speaker output with high volume mode. ( For normal sensitivity speakers  ). 
The left 1st digital display 2:   Speaker output with low volume mode . (  For high sensitivity speakers listen by low volume ). 
The left 1st digital display 3:  Headphone output with low volume mode . ( For normal sensitivity headphones ). 
The left 1st digital display 4:  Headphone output with high volume mode . ( For low sensitivity headphones , low output level sources ).    

Please note :
A , The Precision 1 have large power output, so for most headphone just need working on low volume mode . 
B , Only for some low sensitivity headphone or connect with the devices which have very low output level can choice the high volume mode .
C , Select the volume modes from low mode to high mode, the volume will reset to 0 for avoid the output power increase a lot.
　

Selector button:
         Select the output source.
         The left 2nd digital display 1 : ACSS input 1.
         The left 2nd digital display 2:  RCA input 2.
         The left 2nd digital display 3 : RCA input 3.
         The left 2nd digital display 4 : RCA input 4.
　

Volume knob:
        Turn Left :     Reduce the volume. (Show on the left 3rd and 4th digital display )
        Turn Right  : Increase the volume . (Show on the left 3rd and 4th digital display )
        Because different sources may have different output level, so before select the input sources, reduce the volume is more safe .
　

Rear view:

Power connector:         For power input.
IN 1 sockets :              ACSS input .
IN 2 sockets :              RCA input .
IN 3 sockets :              RCA input .
IN 4 sockets :              RCA input .
Output connectors:      Speaker outputs .