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Accept pre-order

Based on some customers advices and help to design the new chassis, we plan to build the new style chassis for it.
Pre-order only pay a deposit of USD150 (non refund)


    
The first batch 5 units had sold out.
The second batch 25 units , had pre-order 15 units.

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Master 1 Vacuum

8 pc vacuum valves preamp
Without built in silicon elements on signal and power circuits

All power caps built with SOLEN film caps
All vacuum valve filament power supply by AC
Remote function

Price:     USD1630 (Exclude shipping cost,included metal remote controller)
Please send your address, name  to
audio-gd@vip.163.com get the quote.

  



  

   
Summarize Use Manual Specs Custom Option Shipping Cost


Please note before place the order¡G

          Master 1 Vacuum design and building may different to others.
          It is the most pure vacuum valve unit, in the power supply and signal channel, only built with resistors, caps and vacuum valves.
          It had not built in power regulators for vacuum valve's filament and signal channel.
          It had not built in choking coil and electrolytic caps in power supply, only with the small capacity film caps and vacuum rectifiers for rectification and power filtering.
          It through the especial design boost the SN over 98DB on the normal listen volume .
          So its sound may has some different than some vacuum valve units you have ever listened with .
          With Master 1 Vacuum, you can not hear the vocal sound like thick but that like the singer stuff something in the mouth. You also can not hear the much warm and slow sound .
          With Master 1 Vacuum, you can hear the transparency , detail and dynamic sound but with the tubelike and musical sound  ,and a little warm.

Design concept¡G
          All active components have the nonlinear character , it can not has the perfect on every side . While we designed the unit, we had to choice the perfect area of the components .
          We had consider the most power amp that had around 1V input sensitivity, while the preamp output 1V level, the power amp got the full power output, so we decided make the perfect area on the 2V and below output level , though its max output over 15V  .
          About the frequency band, we have not looking for the best specs on paper, but we have through the long term listen and adjust to confirm the final parameter .
          Master 1 Vacuum had built in two pc same board for L and R channels, we have not design the mirror board, because the vacuum valve can not as the transistor that can assemble in the mirror design board with invert the part's forward, the vacuum valve can not assemble with invert forward,  if apply the mirror design, must make the different layout cause the different performance between L and R channels, and effect the sound quality.
          The power filtering caps and signal couple caps all applied the SOLEN film caps , and the built in vacuum valves which is we had test some lot different models and this is finally choice , they  is the best combo based on my over 15 years building experience .
          We are advice the users even have the DIY skill and tons  money, but don't change any built in parts for keep the unit has perfect match on musical and precision  .
          Most vacuum preamps have around 20DB gain, nowdays most sources have over 2V output level, that make the volume control become difficult .
          Master 1 Vacuum had 11DB gain, it allow control the volume quite smooth .


Vacuum valve course of mine  :
           In early of 1990'S, the local business men bought some warships and took off the parts for sale , but no one bought the vacuum valves, so I can got several hundreds KG vacuum valves and start the vacuum valve course .
           After 15 years built and studied (I was stop build vacuum valve units in 2007) , I picked up some experience .
           1¡AFilament must power supply by AC for got the pure tubelike sound.
           2¡ANever apply electrolytic caps , must apply film caps and can not apply large capacity caps.
           3¡ANever apply power regulator.
           4¡ANever apply choking coil, it offer the choking coil sound but not tube sound.
           5¡AMust apply the vacuum valve rectifier .
           6¡AFull wave rectification is necessary but if you looking on our design diagram, the full wave rectification is different to most of others .
           7¡ANowdays the sources have high output level, the preamp only need low gain design.
           8¡AThe most pure vacuum valve design has the most pure tubelike sound.
   
      
Especial design of the unit :
           Some vacuum valve units have applied the DC power regulator for the filament, high voltage or big caps or choking coil for improved the SN .
            Master 1 Vacuum went with other way , it had applied the especial design to improved the SN .
            The design not only improved the SN but improved the transparency, detail and distortion on sound .It is the key of the unit .

Current mode volume control system  :
           The normal volume control had applied the potentiometer ,the signal must through the potentiometer then feed to next stage , the potentiometer must effect the sound quality a lot .  
            Master 1 Vacuum had applied the current mode volume control, the signal only through a resistor then feed to the next stage, without through the volume control port . I publicised the design on <Radio & TV> in 2005  .

Improve on distortion :
           Vacuum valve is nonlinear components , its character is input signal level higher cause distortion increase , and the low and  high output signal level cause the distortion increase .
           We have design the dual volume control ports for improve the distortion.
           The first port places at the preamp input, for limit the input level avoid the high signal level cause the distortion increase .
          The second port places on the gain vacuum valve output, to select and apply the perfect area of the vacuum valve.
           For the stronger output ability, there are two vacuum valves parallel connect as the buffers after the second volume control port.



           Through the especial design, the THD+ noise under 0.05% , and you can see the level is flat between 20Hz -10KHz, and roll off over 10KHz .
           The well know character of the vacuum valve is sound musical , but another is the bad discreteness .
           We had test the same batch vacuum valves, the best and the worst cases which had  around 100X times different on the THD level .
           For promise on the sound quality and performance, we have spent a lot time to check every vacuum valve in the heat state by the Audio Precision equipment, then choose the matched vacuum valves assemble in the units , return the un-fit vacuum valves to the distributor .

  
          
Improved on the transparency and detail :
           This theory may difficult to understand if you don't know the electric technology .
           The vacuum unit has high noise output level , if the detail music signal has low level which is similar to the noise level, it will be kill by the noise and lose , you can not hear this detail music signal .
           Allow me to try to explain by my poor English .
           For example, the preamp output noise level is 0.5MV, which is a good preamp level .
           While the output music detail signal less than 0.5MV, it will kill by the noise  . Even the music detail signal level over than 0.5MV, like 1MV, because the noise kill half of it, it become the larger distortion signal but not the original signal anymore.
            You can image, with the normal vacuum preamp , most time listen the music signal up to 300MV or 500MV in home, but lost all signal less than 0.5MV, how bad of the dynamic and how large signal had lost .
            With Master 1 Vacuum design, the 1MV  output  detail music signal, the unit will gain it up to tens times, then through the second volume port attenuation back to 1MV .
           This operate has some advantages :
           1, gain the weak signal up to tens times  , far away the noise level for avoid effect by the noise level .
            2, The vacuum amp has increase the distortion while the output is weak, gain to tens MV can reduce the distortion .
             3, Attenuation the music signal from tens MV back to 1MV but in same time the noise also had attenuation . For example if attenuation 20MV music signal back to 1MV, the 0.5MV noise has reduce to 0.025MV , so the SN has a larger improve.

SN had been improved :
           Sound quality good or bad is depend on the personal sense , but the SN good or bad , customer can feel it easy . Some vacuum valve preamp , on the normal listen volume, pause the music , may can hear the hum at 1 or few meter from the speakers .
           I have checked an USA made preamps over USD8000 in Chinese market, it had 84DB at 2V RMS unweighted .
           Master 1 Vacuum SN parameter diagrams.
   

   
              Because the especial design, put 2V RMS as standard, the unweighted SN level while the volume on 10 steps, SN is 109DB, and volume on 30 steps, SN is 104DB, and volume on 50 steps, SN is 98DB , and volume on 70 steps , SN is 91DB, volume on 90 steps has over 2V output, SN is 84DB if still count 2V standard but in fact it should has higher number.
              The SN is supper excellent on the low volume can promise the low volume has more detail reproduce without lose . On the other hand, some  vacuum preamp, in low volume, the detail lose more than high volume .
              Usually I listen the music with volume 30-50 steps, it mean the Master 1 Vacuum can promise the SN over 98DB in normal listen.

Volume control character :
               Master 1 Vacuum has 95DB volume control range , under 15 steps, the volume increase few DB on every step, over 15 steps, it has 0.75DB increase on every step, allow smooth and precision to adjust the volume .
              For avoid the noise pick up, the volume control board had shield by a copper box .
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