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HE-1 LE
(HE-1 Linear Power Edition)
Real Balanced ACSS Pure Class A Preamp
　

Price: USD1599  ( Exclude shipping cost . Include combo remote controller that can control the product and some lot audio-gd latest DAC models . It need two AAA batteries support by users .)  
  
Please send your address, name  to audio-gd@vip.163.com get the quote.

What's new in the HE-1 LE:
         The first generation HE-1 released in 2015 years.
         Since 2016 years , some lot customers asked me , do you have plan to upgrade HE-1?
         The analog circuits design is slower develop compare to the digital design. Especial the excellent design.
         In our product upgrade policy, we don't want declare the upgrade edition but just change the chassis or re-arrange the inside , no real upgrade on the design and sound quality.
         Since the first generation Master-1 released, we have not change its design , we always like to upgrade the design but we can't .
         After 9 years, in the 2021 years we spent the long term test and audition, now we are release the new version, it apply the perfect layout technology,   sound quality improve obviously, better detail and dynamic but more analog sound, no harsh anymore, and the functions also upgrade:
         1, It has two gain modes for user select to match with the different gain power amps.
         2, It has double volume control can match well with the different output level sources.
         3, The new design apply the same board of Left and Right channels that make the design exact same,that we can measure and match the boards for assemble in the one unit to ensure the consistency .

What's different between HE-1 LE and HE-1 MK2:
        The HE-1 LE and HE-1 MK2 have share the exact same analog board. The most different is the HE-1 MK2 has built in regenerate power supply that can filter all power line interrupt, feed the most clean power to the analog boards .
       The HE-1 LE has built in the linear power supply , benefit from the built in pure class A PSUs that can offer the quite clean power to the analog boards.
       If customer want the best sound quality, choice the HE-1 MK2.
         http://www.audio-gd.com/HE/HE1MK2/HE1MK2EN.htm
        If customer want to get the best rate of performance and price, or already own the good enough external power processor, choice the HE-1 LE .
      

HE-1 LE summarize :
Fully balanced class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
Non- feedback ACSS analog output stage.
Uses three R-core transformers (In total 145W ) and more than36,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery.
4 group class A PSUs power supply for Left and Right audio signal amps .
Four-channel 100 steps digitally controlled relay-based volume control avoids channel imbalance and improves sound quality.
Four-channel 9 steps digital controller relay-based pre-volume control can control the source input level from 0DB (Bypass) to -8DB.
Two gain modes, high gain has 16DB and low gain has 6DB, which is more flexibility for the different gain power amp .
5 analog inputs:  RCA X2, XLR X2, ACSS X1 ( Even with RCA or XLR inputs, the output still had ACSS aviable)
3 outputs:   XLR / RCA / ACSS (ACSS and XLR/RCA have the separate output circuit design so they can connect 3 units power amp  simultaneously)
　

Detail of the Current Conveyor Technology

Unique real non-feedback ACSS technology:
             HE-1 LE is a true balanced design applying the newest ACSS design which can improve the XLR connection to sound as good as the ACSS connection. The HE-1 LE seem 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 simplest and shortest signal journey brings out the most neutral and least colored sound.
            HE-1 LE applies ultra-low distortion single stage ACSS amplifier , an OPA already had built in two stages amplifier. they are soldered directly on the motherboard.
            The ACSS is a non-feedback technology made with 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 area, all transistors work in class A mode and applies class A power supplies.
             HE-1 LE has all components of four channels exactly matched before installation.
             Uses three R-core transformers (In total 145W ) and more than36,000uf audio grade NOVER capacitors are used to ensure ample and smooth power delivery.
             4 group class A PSUs power supply for Left and Right audio signal amps .

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 HE-1 LE, 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 . After the volume , there are four groups  FET non-feedback buffer output stages offer the very low output impedance  .
            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 HE-1 LE 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.
            HE-1 LE 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.

           Supper Exponential volume characteristic    The Volume steps comparison to normal volume knob       
                                                              

Shield: 
         HE-1 LE has complete separation of left, right amplifier channels, and transformer, even the 230V / 120V power input lines had shield in the two thick aluminum boards .
         HE-1 LE uses heavyweight all-aluminum  chassis to prevent the eddy current of transformers from interfering on circuit board.