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R-27 MK2

Truly balanced fully discrete r2r ladder DAC,
Truly balanced fully discrete headamp/preamp,
ultimate all in one unit

 

    

      

   

Note: The manufacturing process and design can be updated and upgraded at any time so internal and external changes to the actual product can occur without notification.
 

Summarize Use Manual Specs Custom Option Shipping Cost


Price:
 USD2099 ( Exclude shipping cost . Included metal remote controller.)  
Two chassis versions available, customer must inform while place the order ,otherwise we ship the edition randomly:
R-27MK2 Black
R-27MK2 Silver


Please send your address, name  to audio-gd@vip.163.com get the quote.
Please note:

       The R-27 MK2 sound is ultra revealing, if connected with the low grade source or play the low quality music like the MP3 format that you only can hear the low quality sound .


Click to download the driver of  Amanero combo 384

     

Design overview:

        Fully discrete parts are used in a truly balanced current transmission design.
        4 sets of fully discrete and independent DSD hardware decoders.
        8 sets of fully discrete R-2R DA modules to form a two-channel balanced push-pull decoder.
        2 top-notch Accusilicon TCXOs with frequencies of 90 and 98MHz provide synchronization for the whole unit, and they are applied to the playback of all data rates without PLL up-conversion.
        Both the USB and HDMI inputs are equipped with isolators, and a linear power supplies to separately supply power to the USB and HDMI modules before the isolators to prevent interference from signal sources.
         a, USB uses a two-way transmission isolator, which not only transmits IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor. The USB interface itself is no longer equipped with clocks. The synchronous clock is applied to make the signal transmission more accurate and upgrade sound quality to an excellent level. The sound quality is improve obvious.
        b, the HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.

        Through firmware update can conversion the IN2 coaxial input become an external 10MHz clock input ( 75 ohms ).
         All digital mode settings can be changed on the front panel live.
         A firmware upgrade port is featured on the rear panel of the machine (no need to open to take off the cover to upgrade the firmware).
        Unique real non-feedback ACSS headamp
applies four channels of  non-feedback output stages composed of 8 pieces of  transistors, every piece has 15A/150W performance. The capacitance of the whole machine reaches as high as 25,000uF. Three R-core transformers are used with total power of 150W.
       
Large output power 15W at 25 ohm, 1300mW at 300 ohm that can drive most headphones easy.
        Mulriple information display, support user custom display information area  .
    

        More digital technology explain of the R-27 MK2 , please refer the R7HE MK2.
        http://www.audio-gd.com/HE/R7HEMK2/R7HE_MK2EN.htm

 

Unique technology apply in R-27 MK2:
1,Unique Jitter elimination technology:
        Jitter has always been regarded as the root cause for sound quality of digital systems to be inferior to that of high-end analog systems.
       In some traditional DAC designs, the clock processing method is to follow and to restore the clock of the signal source, and some designs also include the capacity of reducing jitter, but with limitations when the jitter level is large.
      This common solution allows getting good measurements in lab tests. But in actual use, most signal sources have large jitter levels, so that the resulting sound quality will not be satisfactory.
       Some DACs worth only USD150 measure better then than some well-selling DACs of foreign brands worth tens of thousands. Who would think that this USD150 DAC is better? This reminds me of when the China Insurance Research Institute tested a direct collision between two brands of cars not long ago, and netizens commented on the car that scored higher in the test: "It has not failed the test, but it has not won the actual battle either."
       The following three product charts are from three DACs of different brands, guess which one is the most expensive? (The answer is at the bottom of this page)
Product A
       
Product B
        
Product C
         
          In order to completely eliminate the influence of jitter in the incoming signal, the R-27 HE uses an asynchronous clocking process.
          First it reads and stores a considerable amount of signal source data to RAM, discard the clock of the signal source, and directly use the high-performance built-in Accusilicons to clock the output from the RAM. Since both data and clock are handled by the FPGA, the impact of transmission on jitter is neglectable. The jitter level is essentially the same as what is specified for the TCXO clocks used by the R-27 HE.
       
       
       The key to this processing method is to ensure the integrity of data transmission, which is our technical secret. Realize that as soon as a single data sample within a million is lost in the transmission, a sharp and obvious cracking sound, like static, or a scratch on a vinyl, will be heard during playback.

        Mr. He is passionate about music and, too him, listening sessions are a source of inspiration for new design ideas. Our cie does not only have the advantage of having full control over software and hardware technology, we also possess a correct understanding of music reproduction.  Without having to rely on outsourcing for R&D, we can at any moment listen to the gears during development, allowing the pursuit and realization of the most realistic sound reproduction.

        Because the local clock and the signal source clock are completely isolated and run independently, the traditional jitter measurement methods can not be applied, instead a special data acquisition circuit is required to evaluate its level. For human beings, the best test method is always through listening tests. A jitter-free sound is very realistic and natural, as clear as pure water, and very involving.

2,Unique real non-feedback ACSS headamp/preamp technology:

           R-27 MK2 built in a true balanced design applying the newest ACSS design . It seems complex , but in fact they are the most simple design the world has ever had , their a lot components to process the power supply. The R-27 MK2 built in amp only has a single " voltage" gain stage to process signals, but works in ACSS mode so in fact it is a current gain stage instead of voltage gain stage, whereas normal OPA chips already include two or three voltage gain stages. The simplest and shortest signal journey brings out the most neutral and least colored sound.
           R-27 MK2 applies ultra-low distortion single stage ACSS amplifier and soldered directly on the motherboard . The gain stages and the diamond cross output stage working on pure class A state.
           The ACSS is a non-feedback technology made with fully discrete amplifiers. Most people know the global feedback design can offer better specs in test measurements, and non-feedback can't do well in test measurements but can offer better sound for the human's ears. Here is a conflict of the classic circuits. But the ACSS opens a new field, it can offer a least coloration sound which is more neutral with very low distortion and high linearity. So it can retain the dynamics, detail and neutral sound but not sound bright or harsh.
           All signal gain is in current, achieved by the unique, superb open-loop multiple output current mirror. Incomparably precise and ultra-low distortion in the gain signal is the result. The signal path is balanced throughout and all transistors work in class A mode.
          R-27 MK2 applies four channels of  non-feedback output stages composed of 8 pieces of  transistors, every piece has 15A/150W performance. The capacitance of the whole machine reaches as high as 25,000uF. Four R-core transformers are used with total power of 150W.

     

3,Unique I/V conversion volume control technology:

 
       The volume control is also different from conventional technology. Conventional volume control technology is the volume control implement in the analog amp input stage through a volume pot to reduce the signal  . The volume pots quality effect the sound quality direct , the low quality volume pot cause lost the detail and channels imbalance cause the soundstage distortion  . Even the high performance volume pot ,in the attenuation then gain the signal mode ,still cause the detail lose and cause the S/N worst .
   
       In the R-27 MK2 , we applied the I/V conversion volume control , the volume control just  a variable passive I/V conversion place at the ACSS amp output , where the output is the current signal, not the voltage signal. The volume control is I/V conversion, and the volume depends on the current (I) conversion to the voltage (V). (Like R-2R D/A chips output passive I/V conversion)  It can keep the signal frequency band flat and not lost any detail. It can't degrade on sound quality in every volume level .

            The volume control quality is much important in the real balance gear . It must guarantee the four channels signal control exact to achieve the performance of the real balance gear .  If the cool and hot of the balance signal can't guarantee exact, the balance output will has large distortion cause the sound quality and performance even much worst than a single end gear , waste the  balance gear  design and the cost.
            In
R-27 MK2 is applied a four channels digital control relays based volume control, through changing the tolerance 0.05% resistors to control the volume for avoid channels imbalanced ,achieve the best performance and sound quality of the gear.
           
R-27 MK2 have 100 steps volume control, applied Supper Exponential Volume Characteristic, easy match the volume with different power amp and speaker .While change the volume, the different relays break or close, it may had slightly switch sound on output and disappear while stop change the volume.


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Product A :USD150 DAC

Product B :USD5000+ DAC American P brand DAC
 
Product C : USD10000  British E brand RIAA front
 

 

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