Monday, May 17, 2010

Sansui AU-9900A (***Updated***)

The Sansui AU-9900A is one of all time favourite units. It is know as the AU-10000 in Japan. You can view many details pixs of the unit at the AMP8 (Japanese) site.

Unknown to many Sansui fans, the 9900A is one of the rare Class-A units produced by Sansui. I managed to locate the service manual which confirms via 50mV setting via adjustment of the trimmers on the main driver board.

I was not aware of the above until I  managed to get a unit from eBay and paid for postage from the US. I initially though I bought a faulty unit when it was running warm and then hot!!! Had to get a dedicated fan to suck the hot air out before the exterior of the units was reasonable to touch!!! Unfortunately the fan is a little noisy ... (need to obtain a less noisy fan)

This is the pix under the covers.
You can see the original capacitors (some deformed) on the PSU board below. Please be aware of the bi-polar caps on the power board.

This is the original pre-amp driver board. Before re-cap, you could heard some raw-ness in the reproduction, especially on the high frequences.
Original pre-amp board
Pre-amp board after re-cap

The original AU9900A sounded so good I sold my AU-20000 (and kept the 9900A). The AU20000 was considered by many to be the top of the line integrated amp from Sansui!!!

The following is the pix of the main driver board after it was recapped. Took the opportunity to swap out some cheaper parts with better quality ones.


  1. Dear WCK,

    I am also an avid fan Vintage Sansui.
    But failed to own this exotic AU9900a, AU10000 or AU20000.
    After your recapped and upgrading job done on this AU9900A only then you compared with AU20000, and you said AU9900A is far better than AU20000. May I know, did you do any upgrade job for the AU20000. Is it fair to compare this method?
    It is great you are able change the original input 120V and change to 230V.
    I am thinking of the same like you and buy one 100V/120V unit and change to local 230V.
    Also, did you do this type of similar upgrading job, if let's say, I need one from you. Of course, I have to pay you. I am from KL, Malaysia.

    Many Thanks


  2. Hi Chew,

    I had both AU9900A and the AU20000 together in original form when I did my comparison.

    I found the AU9900A presentation to my liking as it produce a much warmer and more balance presentation. The AU20000 had a very fluid mid and superb high but lacking in lows. Hence I decide to retain the AU9900A and let someone else appreciate the AU20000 in it's original form.

    After I sold my AU20000, then I perform maintainence on the AU9900A.

    Please note the difference between mod and maintainence. Mod means you change part for another with a different value or different item(s) - add more or remove some. Maintainence means you replace the part with the same value but of difference quality.

    On changing the voltage of the units, some are straight forward. In the case of the AU9900A, there was an internal jumper setting. I find such to be the case for most of my Sansui units.

    I prefer doing tweaking with better quality parts to optimise the performance of the unit. This requires a good ear.

    You can get any repair shop to change the transformer for you, if it cames to that. However, most shops will not have the ear to tune the item for you.

    Case in point. I regularly use a repair shop near my home. The chap does a good job for me and even services high end items such as Sunfire, Accuphase, Arcam, etc. The repair chap admits he can repair the items without issue but does not have the ear to tune it accordingly.

    I can assist with the tuning portion.

    1. Hi WCK,

      I just ran across your blog, I’m starting the rebuild UA9900A, could you share you parts list with me? I’m really interested in your upgrade to F2691.

      I hope you could help,


  3. And apologies for the mistake in the article. I had amended it to say as per my reply to you

  4. Dear WCK,

    Technically speaking, my prefered choice is the bigger the watter, it controls the bass better. I hoped you have not mixed up with that.
    This "...lacking in lows" could easily be explained as leaner bass / well controlled bass / more refined bass, or any other similar terms.
    I hoped to be able to explain that you liked the AU9900a more than AU20000, is more of a personal liking. Hope that you are able to prove me wrong.
    I am particular very keen to know the total cost for the work done on AU9900a, if you don't mind. Because I am pinning hope to acquire one, if possible.

  5. Hi Chew,

    Sorry your theorectical explanations are unable to expain my comment of the AU-20000 lacking in bass.

    My slightly tweaked Audiolab 8000A has better and more well defined/refined bass than the AU-20000. Based on your wattage "theory", it should not be so. The vid in the 8000A does not do justice to the live presentation. When I played that piece on the Audiolabs, it really does sound "live" - we have a U21 piano in the home.

    Please do note shipping costs from US and Europe has now increased dramatically compared to when I bought the AU9900A. If you spare cash, then please ensure the units have a label on the back of the unit, supporting multiple voltages.

    Truthfully total cost is dependant on quality of caps you wish to wish to use (or how "well off" you are!!!). If you are very "well off" and can afford the best aka blackgates, then each cap can cost atleast USD$50 (or higher!!!). The cost of the caps alone can buy another unit (inclusive of S&P too)!!!

  6. Desr WCK,
    I am a little disillusioned now.
    Sorry, please don't get me wrong that I try hard to find fault with your precious AU9900a.
    I bought my first new AU6900 2x60w against new AU7900 2x75w then after comparing both with the same equipment of course. The AU6900 give me a big boost in the bass region, I loved that so much then.
    There is a clue here for me to share with you. You do not have to agree with me, of course.
    I found that Sansui Co. has a tendency to give its smaller watter some form of bigger bass or better bass kind of feeling by of course tuning it upward.
    Subsequently, other areas of the musical spectrum will suffer a little.
    My regret of owning the AU6900 was not immediately known. There were many years later, after many auditionings mostly on Sansui then realised that point. The AU7900 give me a more balanced musical output over the entire spectrum.
    Note: all the above are just my personal opinion only.
    Those blackgate can be so expensive!!!

  7. Hi Chew,

    No worries.

    Different series of Sansui's have a different tonal signature.

    I still own the AU-9900A as well as a AU-G90X, C-2102, B-2101 and B2102 along with the TU-D99X.

    Sold my tuned AU-4400 to a good friend who treasures it. My friend (and self) found the AU-4400 to be extremely well balanced. Only reason for selling it was I did not have the matching tuner and wanted to retain complete sets. Too many misc items in my collection at the moment.

    Other Sansui's I previously owned are AU-101/555 (not the 555A)/217/4400/5900/20000/SE-7.

    Only sold my AU-5900 (within a week after getting it recap) as the buyer for my pair of Arcam Alpha 8 power amps insisted on taking the lot or nothing!!! My mistake for using it as a pre-amp. Must admit the set sound very sweet while I had it though...

  8. Dear WCK,
    Since, you have owned both British & Japanese amps, which do you like most in term of sounding signature. Perhaps, which is more accurate. I used to meet people say "sweet". Does "sweet" & "warmth" constitute any accuracy in music, or just mere liking individually.
    Would you serious wanted to own a very expensive amp, but come without the output protections for your precious speakers.
    Just curious to know what speakers you used to partner with AU9900a, you do not have to reply if you wanted to keep to yourself.

  9. Hi Chew,

    I have a pair of Celestion SL6s, Quad PRO63 and Meridian A500.

    Using a pair of Whafedales for my BeoCenter.

    How about yourself?

  10. Dear WCK,
    You had forgotten to give your opinion of whether British or Japanese amp. Please refer to previous post.
    I owned a pair of very old B&W DM10, but upgraded to Titanium tweeter and also had new thicker (1")& bigger cabinets.
    A lot of friends also said that they like the new configuration, although, not original any more.
    The old cabinet has a lot of boxy resonance because of its thin wall design.
    The mid/bass driver need another round of taming the driver resonance. Hopefully, giving another boost in overall performance.
    Do you have any interesting tips for improvement that i can perform further.

  11. Hi Chew,

    I prefer warm sounding sets which extracts much detail from the media and as close to "being there" as possible.

    In a blind test it would be hard to tell when comparing my "maintained" and/or lightly modded units apart, when comparing against my higher end units like the Meridians, Accuphase, Sugden, etc. In stock form you could tell easily.

    All my speakers are in original condition.

  12. Hi Chew,

    Forgot I sold my AU-9500 as well, with the original blue plastic cover still in-tact on the steel (around the front plate aka "face").

  13. Dear WCK,

    It seems that AU9500 and AU9900a are about the same league as both having about the same power.
    Many said that AU9500 has a more tubey sounding.
    What is choice of the above.


  14. Hi Chew,

    I sold my AU9500 and kept the 9900A.

  15. Dear WCK,

    You mean by keeping your 9900a, it is a much more tubey sounding than 9500.

  16. Hi Chew,

    My choice is the AU9900A. I find it more balanced.

    Found the AU9500 nice with tendacy to be more bassey in all reproductions aka "colors the presentation" or not truly transparent.

    The AU9500 does have a sweet phono section.

    In general the AU9500 high's have a roll-off. Took a while to notice it (something missing but could not quite put my finger on it). Only realised the roll-off when I did a comparison against the AU-G90X and the AU9900A. It was not noticable when compared to the AU-217 which had the same attributes.

    Background details for the AU9500 are acceptable but could be much better.

  17. Dear WCK,

    Thank you so much, now I get to understand more about the position/sounding character between AU9500 and AU9900a.
    I like your explaination on this current post but of course not previous reply post. You should realise that for almost all your earlier reply post, I had to ask a second time.
    Your current reply post is quite easy to understand.

  18. I have AU10000 i bought it from osaca japan at 1978 but from the begining i had a promblem with right becoming warm very soon and im afraid about(in greece we call current silence)what your opinion about this damage?

  19. Please sent to reliable technican to look into