he HE series products had the longest term of design and test  in audio-gd history .  Even though audio-gd had release the regenerative power supply products since 2006, and Mr. Kingwa had publish the article in the magazine explain the technology detail . 
        The HE series products had finished the design in the New Year of 2014 , we were plan to release them in the date of audio-gd 10  anniversary , but for got the best sound quality and performance, we have even 3 times change the full design for made the compare, and compare different power frequency and voltage, create the longest design term record.
       The HE series products have better detail and dynamic reproduce ,blacker backstage ,better focus and larger sound stage , but the sound is better analog .
       The right saddle must is set on the right horse ,if you had not enough good system units, and had not enough cable match experiences, don't waste the money on HE series products.
      Please note the HE series products are upgrade from Master series, even though the price had a big rate increased but the sound quality had not same rate improved.

Audio-gd products had design and test based on the AP SYS-2722 (The top-drawer professional equipment in world) 



Full isolate with the AC power line 
Uses 650W transformers  and more than 100,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery. 
Applies 24 pieces transistors ( in total had 3900W ) to drive the 650W output transformer for 350W AC power output.
Class A PSUs power supply for regenerative drivers  .
4 groups US AC outlet , max power output achieve 350W, enough power supply for DACs, preamps and headphone amps (It can't power supply for power amps)

　

Detail of the Current Conveyor Technology

What's the regenerative power supply :

             While audio is life , the Power supply is water , Pure water create the wonderful life ,clean power supply reproduce the beautiful sound .
             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 , 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.

             
Components:
         Uses all audiophile grade components, including DALE resistors, WIMA caps, custom order NOVER (UK brand) caps, all audiophile grade input & output sockets (Neutrik ) and gold IEC socket.  HE-1 all parts of four channels had exact match before install.

Core:
         Master-2H is a true balanced design applying the newest ACSS design which can improved the XLR connection to sound as good as the ACSS connection. 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 Master-2H power 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.
         Master-2H applies ultra-low distortion single stage ACSS amplifier and soldered directly on the motherboard . The gain stages and pre-driver stages working on class A .
         The output transistors stages working on high idle current state . The diamond cross output stage design can avoid "switch distortion"  as good as the class A amp .
           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.
         The ACSS parts use 4 groups of high-quality class A parallel connection PSU for dedicated DC supply. The class A parallel connection PSU has very high input impedance to avoid pulse from the PSU from affecting the gain stages, and low output impedance with very fast speed and high linear, so it is a very clean power supply.

Drives:
         Massive use of high power parts and robust power supply guarantee vigorous current output that drives most existing loudspeakers.    
         Master-2H applies four channels of diamond non-feedback output stages composed of 80 pieces of “the King of transistors" MJL4281/4302. The capacitance of the whole machine reaches as high as 260,000uF. Four transformers are used with total power of 1700W. 
      
Input: 
        Master-2H can input not only XLR balanced signal, but also the top grade ACSS current signal. No matter what kind of signal it is input, it is able to transfer it to current signal and amplify it.

Shield:
       Master-2H uses heavyweight all aluminum alloy chassis to prevent the eddy current of transformers from interfering with the circuit board.  The interior is separated into 3 sections with aluminum boards for the best separation off the ACSS parts, the output stages and transformers. The AC power wire is shielded by a copper channel from back to front.
          Master-2H take care the vibration for the best sound playback. Each channels gain parts under a 5MM thick aluminum board, these aluminum board not only poise the heat between cool and hot amps, our workers care to install all transistors cling the aluminum board for avoid the vibration cause the sounding worst. From our testing, with the aluminum board bring clear detail reproduce and less harsh than take off the aluminum board .
                                                     
Components:
        Uses all audiophile grade components, including DALE resistors, WIMA & SOLEN caps, custom order NOVER (UK brand) caps, all audiophile grade input (Neutrik) & output sockets (CMC) and gold IEC socket. The output transistors are 80 pieces of “the King of transistors” MJL4281/4302.  Master-2H has all parts of four channels exact-matched before installation.