Sansui AU-D11 II Restoration

stopkidding

Well-Known Member
Hello Sansui fan! its been a while since I have posted here. I used to frequent this place more often, but in the last years, its only been the occasional peek here and there, anyway I digress.

At one point I had accumulated 7 Sansui amps! (AU-G99X, AU-D11, AU-D11 II, AU-7500, AU-607MR(alpha), Sansui 7000, Sansui G-8700DB). A job change, city change and other changes meant that I am now left with just 2, the AU-7500 which I restored myself and the AU-D11 II which I started updating, but lost steam and in the past 2 years and has been moth balled.

I had updated the Phono board, Power Supply Caps, Power Supply Boards and Control boards with new caps and metal film resisters, but there is still a lot to be done. (Tone, Power Amp, trimmers, relays, speaker binding posts) and then testing and tuning. I am looking for a sound reliable tech who would take on this job. I rather spend some money and get this fine amp to its full glory than sit unattended for a few more years! If you have any recommendations, please PM me.
 
The AU-D11 II is an underrated, (or even ignored) amplifier, partly due to its rather flimsy construction and the perception that it is too fiddly with its many trimmer adjustments. There are just a few here on AK who understand just how good this amplifier is, I hope you can find someone to complete the reconditioning of your one.
 
As you may remember I posted, (but lost with the recent site crash), that I had completely re-resistored mine, I wouldn't have done this if I didn't think it was worth it. And hearing the results - to my ears, it was definitely worth it. ;)
 
Oh yes, I remember, unfortunately that won't be possible for me. I have gone through the phono section and updated the resistors, but unfortunately no tech in their right might would take up the task of updating resistors. If you are willing to take up this task, I can provide room and board ;-)
 
As you may remember I posted, (but lost with the recent site crash), that I had completely re-resistored mine, I wouldn't have done this if I didn't think it was worth it. And hearing the results - to my ears, it was definitely worth it. ;)
Seattle is not far :p
 
I have to agree 100% with John, and LWB, the resistor upgrade puts the final layer on a superb amplifier. It's a labour of love so you are probably right, no tech trying to make a living would likely touch it. Find a way - it's worth it.

Angus
 
I have to agree 100% with John, and LWB, the resistor upgrade puts the final layer on a superb amplifier. It's a labour of love so you are probably right, no tech trying to make a living would likely touch it. Find a way - it's worth it.

Angus

Looking at the boards yesterday, I now remember that I had updated the electrolytics and resistors on the phono and tone control boards. So now only the power amplifier circuits that won't get the resistor upgrade.
 
I have just been listening to my fully reconditioned and slightly modified AU-D11 II, and all I can say is that it sounds sublime, astonishing clarity, sound stage presentation, and positioning of instruments and vocals - the equal I think of my reconditioned and modified AU-919. :music:

Something I found to be a good idea is to connect (solder) a stout piece of stranded wire between the rear panel earth terminal and the star ground terminal underneath near the transformer. This makes a difference because despite appearances the copper effect chassis and screens do not seem to conduct with the best efficiency in some places. This addition dramatically improves the important ground connection from the driver boards (F-4266 & 4267) to that star ground, which would otherwise have to go through the chassis. ;)
 
Last edited:
I have just been listening to my fully reconditioned and slightly modified AU-D11 II, and all I can say is that it sounds sublime, astonishing clarity, sound stage presentation, and positioning of instruments and vocals - the equal I think of my reconditioned and modified AU-919. :music:

Something I found to be a good idea is to connect (solder) a stout piece of stranded wire between the rear panel earth terminal and the star ground terminal underneath near the transformer. This makes a difference because despite appearances the copper effect chassis and screens do not seem to conduct with the best efficiency in some places. This addition dramatically improves the important ground connection from the driver boards (F-4266 & 4267) to that star ground, which would otherwise have to go through the chassis. ;)

Thanks for all the useful information. Is there a list of service mods or recommended fixes that one must apply. I have my appointment with the tech in 2 weeks. Would be good to give him a list...
 
Oh heavens where to start... :D

Reconditioning essentials
Change all the electrolytic capacitors. (I used low ESR types for filtering, and elsewhere Panasonic FC or Nichicon FG or ES where appropriate).
Change all the trimmers.
Add the additional stout ground wire, from the rear panel ground point to the star ground underneath near the transformer.

Optional (I have done).
Changed most of the zener diodes, mainly so I could get the hot ones mounted away from the PCB.
Changed the current regulator diodes in the Power Amp.
Changed the original SIP OP amps for DIL8 types using Brown Dog adapters.
Changed the 4 Main PSU capacitors for Nichicon KG, 10,000µF 80V Gold Tune, - difficult+ but worth it.
Changed dual main rectifiers for 'faster' types.
Changed the power amp output emitter resistors for Mills MRA12 types.
Changed speaker relays.
Changed speaker terminals, - difficult++ but very much worth it.

And I have almost completely re-resistored the unit, using metal film ¼ watt and ½ watt replacements as appropriate, the only ones left original are the high wattage grey bodied resistors in the power amp, and in a couple of locations elsewhere.

Some of the above has been covered in threads here by myself (and others).
 
Last edited:
Oh heavens where to start... :D

Reconditioning essentials
1) Change all the electrolytic capacitors. (I used low ESR types for filtering, and elsewhere Panasonic FC or Nichicon FG or ES where appropriate).
2) Change all the trimmers. THREAD >> http://audiokarma.org/forums/index....r-replacement-with-pics.380171/#post-11183979
3) Add the additional stout ground wire, from the rear panel ground point to the star ground underneath near the transformer.

Optional (I have done).
4) Changed most of the zener diodes, mainly so I could get the hot ones mounted away from the PCB.
5) Changed the current regulator diodes in the Power Amp.
6) Changed the original SIP OP amps for DIL8 types using Brown Dog adapters.THREAD >> http://audiokarma.org/forums/index.php?threads/replacing-op-amps-in-au-d11-ii.330811/
7) Changed the 4 Main PSU capacitors for Nichicon KG, 10,000µF 80V Gold Tune, - difficult+ but worth it. THREAD >> http://audiokarma.org/forums/index.php?threads/psu-filter-capacitor-upgrade-au-d11-ii.566144/page-2
8) Changed dual main rectifiers for 'faster' types.
9) Changed the power amp output emitter resistors for Mills MRA12 types.
10) Changed speaker relays.
11) Changed speaker terminals, - difficult++ but very much worth it.

12) And I have almost completely re-resistored the unit, using metal film ¼ watt and ½ watt replacements as appropriate, the only ones left original are the high wattage grey bodied resistors in the power amp, and in a couple of locations elsewhere. THREAD >> http://audiokarma.org/forums/index.php?threads/au-d11-ii-resistor-upgrade.808722/#post-11294994

Some of the above has been covered in threads here by myself (and others).

OTHER: Headphone Service Mod: http://audiokarma.org/forums/index....phone-stage-to-au-d11ii.754952/#post-10311173

Here is what I likely to get accomplished (added numbers to this fantastic list)
Numbers 1, 2, 3 from Required list
Numbers 7, 10, 11 from Optional List
Number 12, partially done. F-4273 (pre-amp) and F-4263 (Phono) boards have been updated with metal film resistors.
++ add metal film WIMA caps on the audio signal path.

I can ask the tech about the rest :-D
 
And it's off! Drive 5 hours to drop off the amp at QRXrestore in Eugene, OR. Now it's in the hands of the nice folks there.

Now for the wait.... Thanks Hyperion for all the helpful advice. I hope to get most of the items from your list accomplished :-D
 
Question regarding PSU filter caps: My tech is working on the upgrades. I had Nichicon Goldtune 10000uF 80v caps for the PSU filter cap upgrade. However the tech feels these may not be a secure fit due to the 50mm diameter. @john - what method did you use to secure these to the PSU board? Glue?

Are the Goldtunes a better option then smaller sized filter caps that may fit better structurally? The options from the tech are Nichicon or United Chemi-con 12000uF 80V caps that are smaller in size than the Goldtunes.

Referencing this thread: http://audiokarma.org/forums/index.php?threads/psu-filter-capacitor-upgrade-au-d11-ii.566144/page-2
 
Back
Top Bottom