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HE-7 (2021 Version)


(Regenerative power supply)

(Apply 8 pcs the most real like sound DA chip PCM1704UK)


Fully discrete real balanced  current transmition design.

2 pc ultra high frequency 90/98 MHz Accusilicon 318B femtosecond clocks provide synchronous clock for whole unit without PLL up-frequency .

32bit / PCM384K asynchronous transfer Amanero 384 apply the FPGA synchronous clock.

Both USB / HDMI have built in separate isolator and pure class A isolate power supply.

The whole digital circuit built with 1 pc FPGA and 3 pc CPLD programmable chipsets to separate the different configured circuits for avoid interrupt, data process in parallel mode.

Support firmware update to improve on sound quality.

Input signal sampling display.

Support external 10MHz clock input (Default is 50 ohm, 75 ohm can be custom order).

All digital process mode settings accessible by buttons on front  (No need  to open the chassis).
Firmware update port accessible on rear (Update  firmware n
o need  to open the chassis).
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Please note: The product improve cause the inside or outside change without inform .
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Summarize Use Manual Specs Custom Option Shipping Cost

Please note: The PCM1704UK can not support DSD playback. User need conversion the DSD to PCM in the source device.
Price:
 USD3680 ( Exclude shipping cost .)  
Please send your address, name  to audio-gd@vip.163.com get the quote.

Apply 90/98MHz Accusilicon 318B femtosecond clocks:
       

Shipped since July 2019, the unit has upgraded the transformers , can power on long term.

Click to download the driver of  Amanero combo 384

HE-7 (2021 version) feature:
1,     USB and HDMI apply the separate isolators and isolate pure class A PSUs for avoid the interrupt from computer and HDMI sources. (New Feature)
2,     USB apply the bidirectional isolator that can transmit the IIS signal to the FPGA processor and receive the clock signal from the FPGA processor, the USB interface without on board data clocks, the signal transmit is much exact, the sound quality get the much improve , better than the last generative HE-7 combine with DI-20 (But not DI-20HE)  level. (New Feature)
3,     HDMI input apply isolator for improve the sound quality . (New Feature)
4,      Input signal sampling display .(New Feature)
5,      Support 10 MHz clock input.(New Feature)
6,      The FPGA process data in the  parallel mode.
         The IIS data is series transmit mode, every data must need one clock cycle to process or transmit, one frame data ( Include L and R data) must need 64 clock cycle to process or transmit, so the data has effect by the 64 clock cycles.
         But the parallel data process and transmit mode only need one clock cycle can finish the one frame data process and transmit, that can avoid the effect of clock stability .
          The IIS input (Include USB and HDMI-IIS) has recombine become dual 32bit parallel data once input , and the SPDIF input after decoder, has recombine become dual 24bit parallel data.
          The parallel process and transmit mode can improve the sound quality on the transparency and detail but still analog.
7,       Full new configuration clock manage design built in, improved on the clock timing.

Pure analogous Regenerative power supply :
            The regenerative power supply like a proprietary electric generator built in the unit.
             It can block most disturb from the power line , supply the ultra clean power supply for the audio amps , reproduce the most neutral and analog sound like audio signal for the system and the users.
             In the regenerative power supply design, the AC power through the regenerative input transformer , conversion to DC power ,through the class A PSUs power supply for the regenerative wave generator and driver stages .
             A balance regenerative regular wave generator produce the ultra low distortion 50Hz wave ,through the balance  gain amps and the strong  output stages , drive the regenerative transformers produce the clean AC power supply feed to the separate class A PSUs power supply for the L and R channel preamps .
            The class A parallel connection PSU has very high input impedance to avoid disturb through the PSU from affecting the signal parts and low output impedance with very fast speed and high linear,  it is a very clean power supply.
             Audio-gd on the regenerative power supply design points  :
             1, Through analyzed the AP SYS-2722 ,do a lot practises ,test and listen , full analog design of the regular wave generator have much lower distortion than the digital generator.
            2, Digital drive stages have higher efficiency , but full analog drive stages have much better analog sound like .
            3, 400Hz regenerative wave have higher efficiency , 50Hz regenerative wave had much far away the human ears sensitivity area than the 400Hz, boost the sound have much better analog sound like.



Pros and cons of PCM1704UK R-2R DAC  :
Advantages:
         1.R-2R will not convert the clock signal into the output signal.
         2. R-2R is not sensitive to jitter while Delta-Sigma DA is much more sensitive to jitter.
         3. The output signal is much more precise compared to Delta-Sigma DA .
Weaknesses:
        1.THD today is extremely good with Sigma Delta chips; R2R ladders are good too but not as good.
        2. Glitches and accuracy of the ladder resistors are very difficult to avoid and require complex technology to resolve it.

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Importunacy of the FPGA/CPLD:
               
 FPGA stands for Programmable Array Logic. 
            Nowadays the FPGA is applied in a lot high end grade DACs; like the popular ROCKNA WAVEDREAM DAC. 
            We have applied the FPGA in our DAC products since 2008.
            HE-7 has built in 1 pc FPGA and 3 pc CPLD programmable chipsets to separate the different configured circuits for avoid interrupt.
            The internal hardware design is fully controlled by complex software. A huge advantage is the fact the software in the FPGA can easily be upgraded offering new features or improve the performance. Such design is much flexible and future proof!

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FPGA/CPLD tasks :
           1. The FPGA high performance SPDIF interface, replacing traditional  SPDIF interface chips like DIR9001, WM8805 or AK411X wich are lower in performance in comparison to FPGA.

           2. Full re-clocking process with FIFO design applicable on all inputs. This way the output data keeps fully synchronized with the clock signal to reject any jitter.
           3. Built in 2X, 4X and 8X oversampling and digital filters and on top of this 4 different true NOS (only analog 6dB filtering) modes. To completely configure it to your liking!
           4. Built in the especial design to simulate the TDA1541A + SAA7220 sound flavor.

Fully discrete output stages

               
The signal last stage is the analog output stages, they can much effect the whole DAC sound quality.
          After d/a conversion by the R2R D/A modules the analogue signal is transported by fully discrete matched-transistor output stages.
          DC-coupled design with first class through-hole components. No SMD components are applied. The high speed special ACSS output stages are non-feedback and current driven design.
          Special because almost all other designs need to convert the signal multiple times from and to current or voltage, resulting in less detail and less good staging.
          The output buffers are single ended FET. Two stages in parallel to reach very low output impedance. All output stages are in pure class A design without any (negative) feedback to achieve purest and a real live sound reproduction.
          The 4 OPA opamps are functioning as DC servo, this way no coupling-capacitors are needed and DC output is automatically biased! Resulting in a perfectly neutral sound.
          There are no relays or other switches in the signal path after DA modules to perform the best and purest sound quality.



Heavy power supplies design:

               
 Uses four R-core transformers (In total 295W ) and more than 95,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery.
16 groups discrete class A PSUs power supply for the regenerative drivers and the digital / analog audio signal parts.
            This results in ultra-high speed and ultra-low noise performance. Clean and independent power for all different parts to achieve highest quality.
           

Finishing touch:
 
            The HE-7 has completely separated power supplies .Digital, left and right analog channel have their own dedicated transformer. All boards and transformer compartment are separated by 5mm thick aluminum plates for high isolation degree.
               It improves the signal-to-noise ratio, isolate the harmonic interference and reduce noise, which will make the sonic background cleaner and blacker.
              The Left and Right analog parts are placed symmetric beside the digital board to keep the wires and distance identical to ensure equal output performance on both channels .
              The R2R DA modules are assembled between two aluminum boards to avoid any RF interferences.

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