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Sansui AU-D707X Or Sansui AU-D907X

Discussion in 'Exclusively Sansui' started by shojam, Nov 18, 2018.

  1. shojam

    shojam SHOJAM

    Messages:
    14
    Location:
    Pakistan
    Hello..
    I just got two amps from an old friend's basement. He told me these belong to previous owner who never came back for left overs. God is great. My friend didn't hesitate while i intended to pick these. Amps were in protection mode. First was Sansui AU-D707X which is a japanese version of G90X. Second amp is bit confusing. Its D907x also japanese domestic 100 volt model with massive 160wpc.

    Now the big question.

    Which amp should i keep for restoration. Coz this 707x is closer to D11ii and 907X uses different power transistors (found in D9, D11 and G99x as per my limited knowledge). The problem is.... Ill have to keep only one. So i need suggestions from you guys... BTW i loved the sonic signature of D11ii and G90x (both at another friend's place who is insane sansui lover).

    Recommendations must carry weight.
    Thanks.
     
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  2. bluesky

    bluesky Addicted Member

    Messages:
    7,605
    AU-D907X

    Just guessing... 907 - with a massive 160 wpc. Power is power!

    Check on availability of parts.
     
    Last edited: Nov 18, 2018
  3. phonomac

    phonomac Active Member

    Messages:
    215
    Location:
    Hunsbury, UK
    The difference in power is not relevant unless you are trying to fill a dance hall, and even then 160W is only 1.2 dB better than 130W. Assuming that the 907X achieves its power rating by using paralleled output transistors like most of the other 907 types I am not in favour of that arrangement. Finally, very suitable new replacement output transistors are available for the 707x/D11 II should they be required.

    So you know from this and other threads what my recommendation is: D707X
     
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  4. bluesky

    bluesky Addicted Member

    Messages:
    7,605
    Just changed my mind :) ... AU-D707X.
     
    shojam likes this.
  5. shojam

    shojam SHOJAM

    Messages:
    14
    Location:
    Pakistan
    Thanks phonomac. I adjusted the DC offset around 0mv across hot n cold terminals. Also adjusted idling current for output devices at 20mv-20.5mv. Is that right ? Coz i was not able to avail SM for 707x, so keeping in view of bias adjustment of D11ii, i performed the procedure on 707x. Its sounding more tight and precise now. My only reservation is about 20mv. Is it right or i should go up???
     
  6. shojam

    shojam SHOJAM

    Messages:
    14
    Location:
    Pakistan
    you changed your mind and i changed to 707x.. It was a right decision my friend. This is a serious machine.
     
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  7. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,550
    Location:
    Hertfordshire, UK
    There's a right amount of bias or a wrong amount of bias - for the AU-D11 II the setting is 20mV, I can only guess that for the AU-D707X it is the same. You shouldn't increase the bias just because you feel it should be more.

    The AU-D11 II runs very cool when set to 20mV (for each of 4 readings) - this is as it should be.
     
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  8. bluesky

    bluesky Addicted Member

    Messages:
    7,605
    Excellent!
     
  9. shojam

    shojam SHOJAM

    Messages:
    14
    Location:
    Pakistan
    Hyperion thanks for suggestions. Yes i have adjusted 20mv for all four pairs. Amp runs cool. Sounds perfect. Just one confusion... The hot ground adjustment is not stable. What should be done to achieve 0 at hot ground.
     
  10. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,550
    Location:
    Hertfordshire, UK
    There is nothing you can do about this, it is an unattainable setting - just set it as close as you can to zero, however it will wander about quite a bit.

    Later iterations of this design address the issue to a considerable extent, I own 3 different Sansuis with this design and they all do it to a greater or lesser degree. (AU-D11 II, B-2102, AU-X701). The AU-α907Limited I recently looked at based on the same basic design, was very good indeed in this respect.
     
    Last edited: Nov 28, 2018
    milo63 likes this.
  11. mbz

    mbz Super Member

    Messages:
    2,256
    Location:
    Melbourne, Victoria
    Have I misunderstood something. Thought/almost certain the AU-D907 series were the domestic version of the AU-919.
     

     

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  12. JoseHH

    JoseHH Member

    Messages:
    86
    Location:
    Now In Bangkok
    You got it right,.The AU-D907 is the Japan market version of the AU-919. In this thread the person that originated it was not sure if he should buy an AU-D707X or an AU-D907X. Some times in this forum the users make brief statements when it comes to mention model names and this could have caused a confusion. The amplifiers they are talking about in this thread are actually quite different from the AU-919, but very comparable to the AU-D11 II.
     
    mbz likes this.
  13. phonomac

    phonomac Active Member

    Messages:
    215
    Location:
    Hunsbury, UK
    You are quite correct. Just me being lazy - I couldn't be bothered to write 907KX, 907MR, 907MRX, 907DR etc.:rolleyes:
     
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  14. mbz

    mbz Super Member

    Messages:
    2,256
    Location:
    Melbourne, Victoria
    Apologies for the alarm bells. Been trying to pickup a AU-919/AU-D907/AU-X... for a while, on that Japanese auction site.
    Whenever I see 907 the brain goes into auto-correct
     
  15. quadklipsh

    quadklipsh Super Member

    Messages:
    1,291
    Location:
    Lahore, Pakistan
  16. quadklipsh

    quadklipsh Super Member

    Messages:
    1,291
    Location:
    Lahore, Pakistan
    707x nudies
     

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  17. quadklipsh

    quadklipsh Super Member

    Messages:
    1,291
    Location:
    Lahore, Pakistan
    3_IMG_20181205_110749_HHT.jpg
     

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  18. quadklipsh

    quadklipsh Super Member

    Messages:
    1,291
    Location:
    Lahore, Pakistan
  19. JoseHH

    JoseHH Member

    Messages:
    86
    Location:
    Now In Bangkok
    Nice amplifiers. The inside of the wood side panel was also finished!. May be you can look at this thread to see if you can rejuvenate the front panel a bit. There may be other tricks known by others.
    Enjoy!
     

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