AU-X11 reconditioning

Discussion in 'Exclusively Sansui' started by Hyperion, Mar 16, 2018.

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  1. SanthoshA

    SanthoshA Active Member

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    If possible can you post pictures or details and parts sourced for replacing the speaker relays and also the speaker terminals, i have a broken terminal in mine, would be grateful if you can add the details in your thread.
    By any chance are you also replacing the RCA lugs?

    I plan to do this in the last or once the other parts of the amplifier are done.

    Nice to hear that the X11 is in good shape !
     
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  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Last edited: May 8, 2018
  3. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Well, this beauty is finally finished, in the process I have changed:-

    118 Capacitors
    10 Resistors
    10 Trimmers
    11 Relays (9 signal relays and 2 speaker relays)
    26 Diodes

    I am just making final adjustments, and playing some test music, then it will be cleaning, re-installation of all covers, and more cleaning. ;)
     
  4. ghamilton

    ghamilton Super Member

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  5. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    And finally

    An underside view (minus right side wood panel)
    IMG_2359.JPG

    A topside view
    IMG_2360.JPG

    A rear view - to show replacement speaker terminals
    IMG_2361.JPG


    And a front view - top cover off
    IMG_2362.JPG

    Has anyone noticed that Sansui spelt 'Toroidal' wrong on the label for the mains transformer? - instead spelling it 'Troidal' :D
     
  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    And compared in size to an AU-717 :D

    Rear panels are lined up.
    IMG_2364.JPG
    IMG_2365.JPG
     
    Last edited: May 16, 2018

     

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  7. Ronito6

    Ronito6 Super Member

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    Looks great!

    How did you clean the RCA sockets? The corrosion that develops there is especially difficult to correct.

    My method of dealing with it is rather brutal.

    I’m rather hoping that you have a kinder process than mine.

    My method:
    • Remove the RCA socket unit from the amp
    • Cut off an RCA plug from off a cheap, or broken RCA cable.
    • Attach that plug to a drill as you would a regular drill bit.
    • Fill the hollow of that makeshift drill bit with gritty type metal polish.
    • Plug the the plug / bit into the corroded socket and press that drill trigger.
    • After all sockets have been cleaned of corrosion, using a long bristle brush, wash the socket in dish soap and tap water to remove the polish residue. Rinse in tap water.
    • Rinse in distilled water until water runs clear and all trace of residue has been flushed away. Use a fresh brush to aid in the rinsing.
    • Do a final rinse with 99% pure alcohol.
    • Allow to dry then reinstall the socket unit
     
    Last edited: May 23, 2018
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  8. phonomac

    phonomac Active Member

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  9. SanthoshA

    SanthoshA Active Member

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    Really nice work John, i haven't started with the rear panel work yet, will surely need your support once i work on the same.
    Glad to see the amp is in nice condition and in good hands :thumbsup:!.
    And yes these amps are so massive in size, and moving them around in the work space up and down is a bit of a gym work out .
     
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  10. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Yes it is, I agree. I tried many things including 'liquid Brasso', 'Brasso wadding', also 'Silvo wadding' and and all purpose metal cleaner called 'Solvol Autosol' - intended for use on car metalwork. I even tried toothpaste, :) a mild abrasive, but this wasn't effective.

    What worked best for me was an overnight application of Brasso liquid, followed by Brasso wadding stuffed into the end of an appropriately sized 'nut spinner'.... (9mm)

    Nut spinner
    [​IMG]

    Then twist and twist until shiny and clean.

    The sockets on this one were badly corroded and some never came back to bright metal, but the thought of fitting replacement RCA's along with losing the 'shorting' capability of the originals, losing the internal RCA PCB's, and then maintaining correct ground paths for the rewired replacements seemed too much. I tested the RCA connectors and the resistance presented by the screens and inners after polishing and cleaning - and everything checked out fine.
     
    Last edited: May 18, 2018
  11. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Thank you Santhosh, of course I will help you all I can regarding the rear panel work. The speaker terminals required a bit of thought, but it all came right in the end. I had chosen ones with a particularly small size of threaded shank, to avoid having to drill out the PCB connector plates too much. The actual speaker terminals turned out to be a bit smaller than I expected - but were still more or less the same size as the originals and required no drilling to fit. I did have to discard the supplied panel insulators and use 'trimmed' power transistor nylon insulating washers to occupy the original square rear panel speaker socket holes, and re-used the original internal plastic spacers. ;)

    I worked with the unit minus its heavy front panel most of the time, and with duct tape protecting the panel (especially the edges), when it was fitted to avoid workbench inflicted damage as much as possible. Nevertheless the unit is formidably heavy, especially dressed up with all its outer covers fitted, an easy 'two man lift' but (for me at least) a bit of a struggle single handed. ;)
     
    Last edited: May 17, 2018
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  12. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I delivered the X11 back to its owner this morning so we'll see what he thinks of it in due course. ;)
     
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  13. Ronito6

    Ronito6 Super Member

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    Yes, normally. I actually bought a Caig RCA cleaning kit with a proper RCA socket cleaner, but the fouling was so deep that it did little to restore them.

    The physical approach I used got them to shine. (Minus the nickle plating which was hopelessly fouled anyway.)
     
  14. MP984

    MP984 New Member

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    I won't derail the technical discussions, but as the owner of this amp I just wanted to thank John for his sterling work. I took a bit of a risk on this amp when I bought it on Rinkya: it was described as 'junk', but X1s and X11s are as rare as hen's teeth in the UK (at sensible prices, anyway), and I bought it at a really low price. My theory was that if anyone could fix it then John can.

    As John mentions I collected it this morning, got back home and ran into a practical problem while trying not to give myself a hernia from carrying this thing. It was too wide for the bottom shelf of my hi-fi rack, which is where my vintage amps usually reside. I had to rearrange everything, which unfortunately was wasted listening time.

    Anyway, the photo below shows it in its new home, and also gives some idea of the size of the amp. It really is a beast, and I can imagine that working on it single handedly was not easy.

    I'm aiming to get some serious listening done in the next few days, but my wife's birthday is on Saturday and strangely she feels that my vintage hi-fi obsession is a lower priority..........................


    Sansui AU-X11.JPG
     
  15. Hipocrates

    Hipocrates Anti-Muppet Subscriber

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    That's a happy amp right there, kudos!
     
  16. MP984

    MP984 New Member

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    I promised John that I'd write a few impressions of the finished amp, so here goes.

    The amp can play music with no shortage of speed, and with great precision. This morning I've been pumping some fast dance music through it at considerable volume, and it has no trouble at all with this kind of material. I've also noticed details in the music that I haven't heard before.

    The second very noticeable thing: my speakers are standmounts (Triangle Signature Thetas). They're on the large side but are standmounters nonetheless. The X11 renders a very, very large soundstage indeed, both left to right and vertically. Essentially it makes the Thetas sound like quite large floorstanders, and in addition they still 'disappear' from the music. Impressive.

    My impression is that this is a neutral amp, it doesn't appear to be adding any particular flavour to the music. However, one observation. I'd describe the Thetas generally as being bass neutral: if the music has bass then they play it faithfully, but that's it. With the X11 the bass output from these speakers is markedly higher: not nightclub levels of sub-bass, for sure, but it's driving as much bass as possible out of these boxes. I don't know if that's simply a reflection of having 160 wpc to fall back on.

    So, even allowing for New Toy Syndrome, I like the X11 a very great deal.

    A final minor comment, while I think of it: the headphone output is excellent.
     

     

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  17. Vintagear

    Vintagear Super Member

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    First, kudos to you for deciding to have an amp of this caliber restored and more importantly - by someone like Hyperion who knows what he’s doing.

    Try running the amp with the “Jump” switch on. That’s the setting I leave my AU-X1 on all the time. You will notice less of that bass impact but IMO the sound is sublime. I drive Bowers & Wilkins 805 D2 paired with a REL S/2 sub with the X1 and it’s just fantastic. 2+ years with this combo as my primary set-up and it still amazes me every time I listen. Give the jump switch a try.

    Enjoy!
     
  18. MP984

    MP984 New Member

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    Many thanks for the suggestion, I'll certainly try that.

    My understanding of the Jump switch is that it bypasses the tone control circuitry and Flat Amp (I'm not sure what the Flat Amp does...), is that essentially correct?

    I'm assuming that it operates with all of the available inputs on the X11. I mainly use the Aux input for the music on my laptop. I don't yet have a record player, so I'm not using Phono.
     
  19. MP984

    MP984 New Member

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    So I've just spent a couple of hours listening to various tracks and experimenting with the Jump switch. There's no doubt that there's a discernible difference in the way that the music is presented.

    At least with my speakers the Jump switch seems to further improve the clarity / incisiveness /attack of the X11. It seems to me that I lose a touch of bass weight and general warmth, in favour of more emphasis on the mid range and treble response. Male and female vocals, and electric guitars, in particular seem more prominent in the mix. Regarding the bass, it loses slight weight but retains good attack and definition: some tracks really hit hard and fast.

    Generally I quite like it, but with one caveat. I'd describe my Triangle speakers as pretty neutral, and with the Jump switch turned on some tracks do lose some warmth. The overall effect can sometimes be just a bit too much on the neutral side for my tastes, and the occasional modern pop track suffers from a touch of noticeable sibilance (which isn't there with the Jump turned off).

    These are my initial thoughts, anyway. I'll play around with it some more.
     
  20. Vintagear

    Vintagear Super Member

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    1,474
    Correct, it will bypass the Flat Amp but since the amp does not have tone controls per se, the primary function is to shorten the signal path with the most obvious difference being a substantial reduction in pre-amp gain. Plus, the amp will be dead silent even at higher volumes.

    All of the inputs will/should work whether you have the jump switch in the on or off position. I also primarily use FLAC and Hi-Res files with an external DAC feeding into the AUX input.

    I suspect the reduced gain setting may even work better for you especially since I believe your Theta’s are very efficient speakers.

    PLEASE NOTE: Do not operate the Jump switch with the volume raised! Always lower the volume all the way BEFORE you switch from one setting to the other because the difference in gain is substantial (I assume it’s similar to the X1).
     

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