R-7HE


(Regenerative power supply)
　

Fully Discrete R-2R Resistor Ladders DAC

Fully Discrete DSD Native decoder

Fully Discrete Real Balance  Current Transmit Design

All Digital Settings By Buttons On Front Plate (Don't want open the chasis).

4 type different algorithm NOS modes, and 3 types different oversampling modes,

have 7 type different sound features,  Can be selection by the buttons on front plate.

Firmware update port assemble on rear, update the firmware without open the unit.
　

         The DAC can setting the digital process functions on front plate to change the sound flavors, without open the unit .

          Since 20th. Mar. 2019 the unit built in tda_asy firmware. The older  V3 firmware function introduce please click to read it     R7_V3 firmwares function introduce.

         Before 10th June R7HE with tda firmware introduce

        
　

Important warn:
         Before push the "Setting" button, I 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 button :
          Push the "Setting" button one time, the one digit display will blink for active the function setting , push the right "Selector" button can change function . While the display blink, push "Setting" again , the right next one digit display will blink , push the left "Selector" button the left next one digit display will blink .
         While the "Dis" LED blink, push the "Setting" one time , the menu will change to menu page 2.

Left Selector buttons:
           While the display non blink, for select the input sources.
          While the display blink, for the setting digit move one left.

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

Menu Page 1:

Syn  (non function in the Asy version) :
           For the 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) .

Pll  (Simulate SAA7220 +TDA1541A sound) :
           Active (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.

OS (Oversampling) :
         "O" for select oversampling, "N" for select NOS mode.

Mode ( OS and NOS modes):
          While OS setting on "O" mean the DAC working under oversampling mode, loIr 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.

Di (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 always.

Menu Page 2:

1st number  (Dither) :
           Active (1) or Disable (0)  dither for all inputs.

2nd number  (non function in the Asy version) :
            For the Syn version if user want to replace other brands USB module in the unit, user can setting the 2nd number ON (1) or OFF (0) to find the best match .In default is OFF (0) .

HDMI 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
R7_tda_Asy don't need MLCK input . Even the source has MLCK output but has not effect .

R7_tda_Asy and R7_tda_Syn firmwares   (NOS mode Support up to 768K)

 What's the different between R7_tda_Asy and R7_tda_Syn:
       R7_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.
       R7_tda_Syn is the firmware running in synchronous  mode, it still need the Mclk signal from HDMI-IIS input.
        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 R7_tda_Asy is the Accurate version and the R7_tda_Syn is the Smooth version.

Update guide:
     R7 update guide


Upgrade Port :
         The DAC can through an USB cable connect betIen computer and "Upgrade Port" to upgrade the firmware for improve the sound quality or performance .

        

In Oct. of 2015 year, I wanted to update the FPGA firmware for the products. That time I did not know the FPGA program design.         I asked some professional friends , give them the function request same as  our older Master 7 V7 firmware , they confirm they can do it but no one could give me a promise on sound quality, even though they asked a quite expensive price, around USD15000 .         I was sad,  then became powerful , I decided to study the FPGA programming.         I went to school every Sat. and Sun. for a half of year .         After I finished the course, even though I worked hard to study every day and night in those months, but I feel I could not to do anything on the project, I was feel I waste that 6 months . How many 6 months in a people life? If you never had the similar experience ,you may can not understand my feel in that moment.         But I have Never gave up.         I bought almost all books in the web shops to studied the digital signal process and verilog language, I also searched on web to study anything about the project.         You may can not image how difficult of an old people to study ,  finally, in Oct. 2016, I finished the first  project ,that was the  Master 7 V7 firmware  .         Some users updated the firmware and gave me the positive feedback , that helped me continued study .                 Few months ago, I got the Accusilicon clocks samples, its ultra specs let me considered design a firmware to let the DAC working on fully asynchronous mode, previous was working on hybrid mode.         I spent a lot time to listen and compare the sound between asynchronous , synchronous  and hybrid modes, finally I finished the new firmware, it offer the best neutral and transparency compare to the other versions but most lively sound. Every detail in sound is so neutral without feel fake. I also finished the synchronous firmware offer another sound flavor.         In the asychronous design, it don't need the input MCLK signal .  I have applied the 98.304MHz and 90.316MHz clocks, that  has enough high frequency allow the clock signal regenerative direct from the clocks but not through the PLL frequency multiplication output.         The PLL output  signal has large jitter compare to the Accusilicon clocks.         The high end sources can do very well and very low jitter on the output digital signal, but in audio field, the both RJ45 or HDMI are not the professional transmit methods, even the source output the perfect signal, during transmit, the different frequency signal had different delay and interrupt cause the signal became worse while feed into the DAC.          I designed an input signal corrector to get the signal , in phase process the signal and clock to perfect state for avoid the signal degrade during transmit.          The regenerative clock is from the Accusilicon clocks,  it has ultra good performance.                               I also applied the new function to simulate the sound of SAA7220 +TDA 1541A.          You can setting the PLL function to 1, but now it don't mean the PLL anymore, it mean the DAC running simulate SAA7220+ TDA1541A configure .          I also designed the new configure NOS mode . The mode support up to 768K sampling input with test.          I have some lot red book discs and a lot time listen with the CD transport, in this firmware, I have done some significative upgrade for the SPDIF input .          Every codes is not only based on technology but through a lot time to audition to confirm .          After you update this firmware, the HDMI input can without MCLK signal. The MCLK is much higher frequency signal than the IIS signal, so it had more sensitivity to the interrupt than the  IIS signal.  The DAC not depend on MCLK input anymore, the sound quality get more promise.           Even the R 7 had not applied Accusilicon clocks but it still can update these firmwares and improve on sound quality .           Different people may has personal listen taste , I can not promise you like this version sound .           This version firmware had not emphasize on detail or transparency, every thing just most neutral and lively .          Give me your feedback to help me improve the firmwares.