Function introduce :
The DAC can setting the digital
process functions on front plate to change the sound flavors, without open the unit .
Since 25th. Mar. 2019 the unit built in tda_asy firmware. The older V3 firmware
function introduce please click to read it
R28_V3 firmwares function
How to active the
digital setting mode:
The "DAC/HP" and "Input"
buttons has dual functions.
While the input between input 5
and input 6, the "DAC/HP" button can select the output mode between
"H" (Headphone output) and "P" (Preamp output) .
While the input is between 1 to
4, the "DAC/HP" button become dual functions.
In case, push the "DAC/HP"
button one time, the left first display flashing around 3 seconds,
in term if the "DAC/HP" button has not push again, the output mode
change either "H" or "P".
If the "DAC/HP" button push
again while the left first display flashing, the unit go into the
digital setting mode.
Before push the
we are advice user turn low the amp volume, stop the
music track playing .
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.
DAC/HP button :
unit had went into the digital setting mode, the one digit display
will blink for active the function setting , push the "Input" button
can change function .
While the display blink, push "DAC/HP"
again , the right next one digit display will blink for setting .
Left 1st display : Oversampling
"O" for select oversampling,
"N" for select NOS mode.
Left 2nd display : OS and NOS modes
setting on "O" mean the DAC working under oversampling
mode, lower number OS modes sound became warmer
and smoother. Or depend on your sense .
Mode "0" : class
technology NOS mode.
Mode "2" : 2X oversampling.
Mode "4" : 4X oversampling .
Mode "8" : 8X oversampling.
While OS setting on "N" mean
the DAC working under NOS mode, it has one mode now, it is the full
new NOS configure design.
Left 3rd display :
SAA7220 +TDA1541A sound) :
(1) : Simulate SAA7220 +TDA1541A, digital attenuation low to -55DB,
was -130DB. Bitwide low to 16bit , was 24 bit. While active this
function, I are advice setting to OS2 or OS4 mode. But infact, this
function can working with any setting mode.
Left 4th. display : (Syn version for correct
HDMI data, Asy version for Dith)
Syn version : If the HDMI input had noise, distortion or some
samplings no sound, user can setting the 1st number ON (1) or OFF
(0) to fixed the issue. In default is OFF (0) .
Asy version : Active
(1) or Disable (0) dither for all inputs.
Left 5th. display : Display
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
the display non blink, for select the input sources.
While the display blink, for
setting the digital process functions.
definitions : (Compatible with PS audio standard)
Pin 1 : SDATA -
Pin 2 : GND
Pin 3 : SDATA +
Pin 4 : SCLK +
Pin 5 : GND
Pin 6 : SCLK -
Pin 7 : LRCK -
Pin 8 : GND
Pin 9 : LRCK +
Pin 10: NC (Syn
version still need the Mclk+ on this pin)
Pin 11: GND
Pin 12: NC (Syn
version still need the Mclk- on this pin)
Pin 13: NC
Pin 14: NC
Pin 15: NC
Pin 16: NC
Pin 17: GND
Pin 18: NC
Pin 19: NC
R28_tda_Asy don't need MLCK input . Even the
source has MLCK output but has not effect .
What's the different between R28_tda_Asy and
R28_tda_Asy is the firmware running in
asynchronous mode, after update it can without input the Mclk signal
from HDMI-IIS input, regenerative inside by the Accusilicon clocks.
R28_tda_Syn is the firmware running in
synchronous mode, it still need the Mclk signal from HDMI-IIS
Some users may don't concern the
technology different, they just concern the sound and they know the
technology advantage don't mean the sound better .
In the simple, you can consider R28_tda_Asy
is the Accurate version and the R28_tda_Syn is the
Firmware update guide:
guide (R28update guide
same as R8)