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Sansui au919 warm up time

Discussion in 'Exclusively Sansui' started by pjrengineer, Oct 23, 2018.

  1. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    does anyone else with a Sansui au919 think that it sounds average when you first turn it on and then after about 1 hour of use it starts to sound dimensional, full and tube like? It is what I typically experience.

    Unlike a marantz that sounds full when you first turn it on.

    It is like a big bond fire that takes a long time to catch but when it does...
     

     

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  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    If it sounds like that it almost certainly needs reconditioning, what you describe makes me think there is excessive switch on drift - a classic symptom of a tired vintage piece in need of attention. If it is in an un-reconditioned state it very likely also has the infamous 'Black Flag' capacitors still present, which deteriorate over time and can lead to serious damage occurring to the amplifier due to loss of stability.
     
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  3. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    This one has had everything replaced except for the filter caps.
     
  4. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Well, something is amiss, although there can be a small difference in SQ after say a 20 minute warm up - but it is very slight.
     
  5. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Could be. Or maybe it is just what sounds good to my ears and certain amps signature sound. I have been very impressed with my tube gear over SS lately. Going to the dark side has been fun.
     
  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Maybe you are blessed with sensitive hearing, but an hour is a long time, so a check of what the bias current is doing would be a good idea I think.
     

     

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  7. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Bias set with new trim pots. Yeah I have sensitive hearing.
     
  8. ghamilton

    ghamilton Super Member

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    Mine sounds great when first turned on and seems to sound the same even after 30 mins.
     
  9. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Yeah it sounds great to me also when turned on but better to me after it is warmed up.

    My friend is having his restored now too. When we get to compare amps in a couple months I’ll report back.
     
  10. ManyMoonsAudio

    ManyMoonsAudio AKA paul79 Sponsor Subscriber

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    An hour warm up is not too far fetched I would say. I have a Sutherland preamp from about 2005 or so, that takes about 3 days to fully open up. I have repeated it numerous times. If I shut it off for a night or what have you, it is a 3 day wait to magic. The Accuphase I am using right now takes about a day to sound best, but that is because the bias rises very slow with this design after power up. I leave these pieces on most of the time.

    This warm up is different with different equipment and different systems. Overall resolution capabilities of your system, speakers, room, etc all contribute as well IME.
     
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  11. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Well I’m not crazy then thanks for your input.

    Honestly the au919 has a little too forward midrange but the highs are at least smooth.

    I also have the 719 and 5000x which I like just as much as the 919 they are just not as rich and deep sounding. But they are a lot less costly.

    What really really impressed me was my newly acquired marantz 2226. So inexpensive and so smooth with lots of bass.
     
    Last edited: Oct 24, 2018
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  12. ManyMoonsAudio

    ManyMoonsAudio AKA paul79 Sponsor Subscriber

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    Yes, the Marantz is warm and smooth, but not near as good at unraveling complexity. Most all your Sansui pieces are good at this.

    Don't discount a more relaxed brain at the end of the day. Night time listening sounding better because it gets quieter outside. These things are also contributors to how you hear. Maybe one of these variables is part of the process you are going through as well.
     
    Last edited: Oct 24, 2018
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  13. kevzep

    kevzep Its all about the Music Subscriber

    This is what I find Sansui's to be very very good at, the AU-X1 excels in this area.
     
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  14. Vintagear

    Vintagear Super Member

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    Curious, do you listen to the 919 with the "Jump" switch on or off?

    The X1 definitely excels at "unraveling complexity". It takes what might otherwise come across as a jumbled mess and lays it out cleanly in time and space. This is how I phrased it when I first reviewed my restored X1 over three years ago.

    "Here’s a weird one, the music sounds slower (in a good way) not in its attack which is awesome but in the fact that the music is not hurried or rushed. It’s like every sound has its place and makes itself known so you can savor it better."

    I've never heard an AU-919 but I suspect it is similar in that respect.
     
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  15. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    On usually.
    Unless I leave the room knowing my girlfriend will use it for Xbox and then I turn it off. Haha. Don’t want her mistakenly blowing my irreplaceable Tannoy drivers.
    It’s somewhat noticeably less harsh in the highs and mids on.

    The problem with the 919 is that because of the power when comparing to other gear i start to blast it to levels that hurt my ears.

    But it is an amazing amp. Just has a thicker midrange and beefier sound than my 719. Which would make some prefer the 719?
     
  16. OnTheBlitz

    OnTheBlitz ->"Dad, It's time to play stick!" Subscriber

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    After an hour are you playing the exact same recording/source, sitting in the exact same location and at the exact same volume level?
     

     

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  17. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Haven’t tried that test yet.
     
  18. Vintagear

    Vintagear Super Member

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    Hmm, I had a 719 and the X1 is in another league. I'm wondering about the "harsh" comment, regardless of whether I have the jump switch on or off I never hear any hint of harshness in the highs and midrange is sublime and just right IMO. What source are you using?
     
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  19. pjrengineer

    pjrengineer AK Subscriber Subscriber

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    Probably comes down to very sensitive hearing and high listening levels. I tend to prefer the smoother sound of tubes or the cap coupled 5000x when listening loud. Maybe these new caps just need break in period. Think I might leave it on for 72 hour period this weekend.
     
  20. JoseHH

    JoseHH Member

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    When you set the bias current, it may have been under special conditions (for example the amplifier being idle for long enough to get the bias stable). When the unit is turned on after it has been cooled back to room temperature, the bias may be slightly lower than that what you had set. Then, after you play music for one hour, the bias current may have increased above the optimum seting, giving you the results you describe. May be -to rule this out- you should measure the bias currnent again after one hour of use to see if you still measure 20mV across the emitter resistors.
     
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