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Sanui Amplifier

vikramjain

New Member
Joined
Sep 18, 2013
Messages
9
Points
3
Location
bhopal
Hi Members

I want sansui amplifiers (like au 919, AU-9500, AU-8500 or any sansui amplifier with 80 rms or abve and i also want a person who can recap it


Regards
Vikram
MB no 8817023459
 
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mshifi

Active Member
Joined
Nov 6, 2012
Messages
699
Points
43
Location
hyderabad
Hi Members

I want sansui amplifiers (like au 919, AU-9500, AU-8500 or any sansui amplifier with 80 rms or abve and i also want a person who can recap it


Regards
Vikram
MB no 8817023459
Vintage amps like these are difficult to get. You have to be on the look out
 

mpasanthosh

Member
Joined
Oct 23, 2015
Messages
41
Points
8
Location
Chennai
Hi Members

I want sansui amplifiers (like au 919, AU-9500, AU-8500 or any sansui amplifier with 80 rms or abve and i also want a person who can recap it


Regards
Vikram
MB no 8817023459
I myself would rather prefer the AU-9900/9900A/AU-919, not a big fan of the 9500 though.
Even if you source them getting them with original output transistors will be a pain.
Recapping is another complicated topic altogether, the vintage amps have certain noisy transistors that could be replaced along with the recap.
If you plan for capacitors like Nichicon Fine Gold/KZ the capacitors will easily cost 50% the cost of the amp, mainly because of customs that gets applied when you import the capacitors. The power supply capacitors, you need to find one that fits the capacitor clamps.
The AU-919 uses oval shaped capacitors if i am not wrong.
Bias pots are a must to replace, multi turns from Bourns are pretty good .
 

kbhuvi

Active Member
Joined
May 17, 2018
Messages
104
Points
28
Location
New Delhi
I myself would rather prefer the AU-9900/9900A/AU-919, not a big fan of the 9500 though.
Even if you source them getting them with original output transistors will be a pain.
Recapping is another complicated topic altogether, the vintage amps have certain noisy transistors that could be replaced along with the recap.
If you plan for capacitors like Nichicon Fine Gold/KZ the capacitors will easily cost 50% the cost of the amp, mainly because of customs that gets applied when you import the capacitors. The power supply capacitors, you need to find one that fits the capacitor clamps.
The AU-919 uses oval shaped capacitors if i am not wrong.
Bias pots are a must to replace, multi turns from Bourns are pretty good .

What about the resistors. Most of the vintage amps have carbon composition resistors which would be out of spec now.
 

mpasanthosh

Member
Joined
Oct 23, 2015
Messages
41
Points
8
Location
Chennai
What about the resistors. Most of the vintage amps have carbon composition resistors which would be out of spec now.
I have replaced most of them with metal film equivalents.
There is though a debate that metal films sound bright, but i never found them bright though.
The difference with metal film compared to carbon film was a much cleaner sound signature.
You could use the resistors from Vishay.
The wire wound resistors are replaced with non-inductive ones also from Vishay Dale.

BUT i have also seen carbon resistors used in the 9900A that have not drifted over the age.
I decided to leave them intact without replacing any.

The ones that need a immediate replacement are those that are burnt/damaged.
If its the driver board i am working on , i replace the same resistors used for the other channel.
 

kuruvilajacob

Well-Known Member
Joined
Jul 11, 2011
Messages
1,196
Points
113
Location
Kottayam
I myself would rather prefer the AU-9900/9900A/AU-919, not a big fan of the 9500 though.
Even if you source them getting them with original output transistors will be a pain.
Recapping is another complicated topic altogether, the vintage amps have certain noisy transistors that could be replaced along with the recap.
If you plan for capacitors like Nichicon Fine Gold/KZ the capacitors will easily cost 50% the cost of the amp, mainly because of customs that gets applied when you import the capacitors. The power supply capacitors, you need to find one that fits the capacitor clamps.
The AU-919 uses oval shaped capacitors if i am not wrong.
Bias pots are a must to replace, multi turns from Bourns are pretty good .
I have few Sansui AU series amplifiers like AU 9500 fully recapped , AU 7900, AU D 90 X etc. I love the AU 9500 which is paired with Allison acoustic speakers.
 

mpasanthosh

Member
Joined
Oct 23, 2015
Messages
41
Points
8
Location
Chennai
I have au 555 Recapped and au 417 in original state.
au 555 phono stage is marvelous.
Yes the phono stage is awesome in these vintage gems.
I use my AU-X11 with Totem Acoustics Rainmaker . The amp never fails to let me down, very impressed with it .
Outright I find it a bit warm sounding but rich in details and the dynamics is so damn good.
 

frend2001

Active Member
Joined
Jul 12, 2010
Messages
368
Points
43
Location
Indore, India
Acquiring a Sansui AU 919 or even 717 today is a task, that too in un-messed condition is almost impossible.

I have seen butchered vintage amps by local techs. Recapping these amps also is task not suitable for half baked techs. These amps are fast current designs with high slew rates so components must be checked, matched and tested before using, assuming a full recap is being carried out. These amps are notorious for corrosive glue used to fix caps on boards which eats into tracks, almost unobtainium black flag caps. Atleast an occiloscope and a function generator is needed to properly do them which sadly is not easily found with normal techs. Although there is ample information available online on recapping them but its a time consuming and costly affair.

Sorry for painting a gloomy picture but the disappointment after a half baked or botched up recap is too painful too.
 

mpasanthosh

Member
Joined
Oct 23, 2015
Messages
41
Points
8
Location
Chennai
Acquiring a Sansui AU 919 or even 717 today is a task, that too in un-messed condition is almost impossible.

I have seen butchered vintage amps by local techs. Recapping these amps also is task not suitable for half baked techs. These amps are fast current designs with high slew rates so components must be checked, matched and tested before using, assuming a full recap is being carried out. These amps are notorious for corrosive glue used to fix caps on boards which eats into tracks, almost unobtainium black flag caps. Atleast an occiloscope and a function generator is needed to properly do them which sadly is not easily found with normal techs. Although there is ample information available online on recapping them but its a time consuming and costly affair.

Sorry for painting a gloomy picture but the disappointment after a half baked or botched up recap is too painful too.
Yes I truly agree, with you.

The AU-9900A was butchered to death when I got to work on the amplifier, and it was bought for a reasonable price from the seller, as he was not able to fix any of the below mentioned issues.

It had a shorted fuse using wire strands, biasing was set too high that the amplifier was putting out enormous amount of heat .
Apart this there were burnt resistors which i had replaced, and also a damaged midrange potentiometer's wafer plates.
1. Damaged Fuses
34946

2. Burnt Resistor Identified During Restore Work
34947

3. Damaged Wafers
34948

With respect to your other two points, i have removed the ill fated Glue using locally available thinner.
Use a small Q-Tip bud and remove the capacitors completely before attempting to removing the glue.
There are cases where the glue even damages resistors in that particular section.
34951

34952

After cleaning the Glue:
34953


The PCB's also reek of slimily residue i belive due to the Glue or Oxidation:
It is better to clean them properly and recoat the PCB's.
Pics from my X11 restoration.
34949

34950


And yes most second hand amplifiers are already tampered on too much to even work or fix it is a big hassle.
From obsolete transistors to obsolete potentiometers it is a big pain in restoring these amplifiers.

I would though recommend to check output transistors for authenticity before proceeding with purchase of a vintage amplifier.
The performance of the amplifier will never be the same with replacement spares !!.

I have confirmed this by using low FT transistors for my AU-X11 during the restore work, when measured with a scope the output of the amplifier starts clipping way before rated power specification . The highs were also a bit harsh to listen to .

After the restoration work i replaced the output transistors with the original sanken's and it made a big difference.
The amplifier could easily put out 160watts at 8 ohms with no clipping, and the harshness in the treble was gone.

I would though recommend bourns multi turn trim potentiometers for the biasing and offset calibration.

After the restore work it is best to load test the amplifier atleast for 10 minutes to watch for clipping distortion etc .

EDIT: The black flags can be replaced with silver micca from Cornell Dublier, I have replaced all the black flags with Silver Micca, in the unobtainium list are certain pre driver transistors and the SV02/SV03 diodes, certain FET's .
To add on these amplifiers are really worth restoring if you can get proper authentic spares, i was faked by eBay sellers many times and had to apply for a refund. So restoring this amp is a pain especially when you need to hunt down obsolete spares.

Cost involved with customs charges will burn a hole in your pocket, it would easily range between 30k till 1lakh depending on the complexity of work and the spares that one needs to change. Calculating a net effective customs charge of 40% on Product cost + Shipping cost.

I have seen these amplifiers sell for exorbitant prices in-spite of being in bad shape to buy them or not is once choice .

My 2 Cents !!.
 
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Last edited:

mshifi

Active Member
Joined
Nov 6, 2012
Messages
699
Points
43
Location
hyderabad
Yes I truly agree, with you.

The AU-9900A was butchered to death when I got to work on the amplifier, and it was bought for a reasonable price from the seller, as he was not able to fix any of the below mentioned issues.

It had a shorted fuse using wire strands, biasing was set too high that the amplifier was putting out enormous amount of heat .
Apart this there were burnt resistors which i had replaced, and also a damaged midrange potentiometer's wafer plates.
1. Damaged Fuses
View attachment 34946

2. Burnt Resistor Identified During Restore Work
View attachment 34947

3. Damaged Wafers
View attachment 34948

With respect to your other two points, i have removed the ill fated Glue using locally available thinner.
Use a small Q-Tip bud and remove the capacitors completely before attempting to removing the glue.
There are cases where the glue even damages resistors in that particular section.
View attachment 34951

View attachment 34952

After cleaning the Glue:
View attachment 34953


The PCB's also reek of slimily residue i belive due to the Glue or Oxidation:
It is better to clean them properly and recoat the PCB's.
Pics from my X11 restoration.
View attachment 34949

View attachment 34950


And yes most second hand amplifiers are already tampered on too much to even work or fix it is a big hassle.
From obsolete transistors to obsolete potentiometers it is a big pain in restoring these amplifiers.

I would though recommend to check output transistors for authenticity before proceeding with purchase of a vintage amplifier.
The performance of the amplifier will never be the same with replacement spares !!.

I have confirmed this by using low FT transistors for my AU-X11 during the restore work, when measured with a scope the output of the amplifier starts clipping way before rated power specification . The highs were also a bit harsh to listen to .

After the restoration work i replaced the output transistors with the original sanken's and it made a big difference.
The amplifier could easily put out 160watts at 8 ohms with no clipping, and the harshness in the treble was gone.

I would though recommend bourns multi turn trim potentiometers for the biasing and offset calibration.

After the restore work it is best to load test the amplifier atleast for 10 minutes to watch for clipping distortion etc .

EDIT: The black flags can be replaced with silver micca from Cornell Dublier, I have replaced all the black flags with Silver Micca, in the unobtainium list are certain pre driver transistors and the SV02/SV03 diodes, certain FET's .
To add on these amplifiers are really worth restoring if you can get proper authentic spares, i was faked by eBay sellers many times and had to apply for a refund. So restoring this amp is a pain especially when you need to hunt down obsolete spares.

Cost involved with customs charges will burn a hole in your pocket, it would easily range between 30k till 1lakh depending on the complexity of work and the spares that one needs to change. Calculating a net effective customs charge of 40% on Product cost + Shipping cost.

I have seen these amplifiers sell for exorbitant prices in-spite of being in bad shape to buy them or not is once choice .

My 2 Cents !!.
Great work mpasantosh in restoring the amps. Getting a good sansui amp is difficult. Had a AU317, AU- D9 which have been sold to forum members. Still have the AU717 which is in good shape.
 

JayaRaa

Active Member
Joined
Apr 14, 2015
Messages
830
Points
43
Location
India
Yes I truly agree, with you.

The AU-9900A was butchered to death when I got to work on the amplifier, and it was bought for a reasonable price from the seller, as he was not able to fix any of the below mentioned issues.

It had a shorted fuse using wire strands, biasing was set too high that the amplifier was putting out enormous amount of heat .
Apart this there were burnt resistors which i had replaced, and also a damaged midrange potentiometer's wafer plates.
1. Damaged Fuses
View attachment 34946

2. Burnt Resistor Identified During Restore Work
View attachment 34947

3. Damaged Wafers
View attachment 34948

With respect to your other two points, i have removed the ill fated Glue using locally available thinner.
Use a small Q-Tip bud and remove the capacitors completely before attempting to removing the glue.
There are cases where the glue even damages resistors in that particular section.
View attachment 34951

View attachment 34952

After cleaning the Glue:
View attachment 34953


The PCB's also reek of slimily residue i belive due to the Glue or Oxidation:
It is better to clean them properly and recoat the PCB's.
Pics from my X11 restoration.
View attachment 34949

View attachment 34950


And yes most second hand amplifiers are already tampered on too much to even work or fix it is a big hassle.
From obsolete transistors to obsolete potentiometers it is a big pain in restoring these amplifiers.

I would though recommend to check output transistors for authenticity before proceeding with purchase of a vintage amplifier.
The performance of the amplifier will never be the same with replacement spares !!.

I have confirmed this by using low FT transistors for my AU-X11 during the restore work, when measured with a scope the output of the amplifier starts clipping way before rated power specification . The highs were also a bit harsh to listen to .

After the restoration work i replaced the output transistors with the original sanken's and it made a big difference.
The amplifier could easily put out 160watts at 8 ohms with no clipping, and the harshness in the treble was gone.

I would though recommend bourns multi turn trim potentiometers for the biasing and offset calibration.

After the restore work it is best to load test the amplifier atleast for 10 minutes to watch for clipping distortion etc .

EDIT: The black flags can be replaced with silver micca from Cornell Dublier, I have replaced all the black flags with Silver Micca, in the unobtainium list are certain pre driver transistors and the SV02/SV03 diodes, certain FET's .
To add on these amplifiers are really worth restoring if you can get proper authentic spares, i was faked by eBay sellers many times and had to apply for a refund. So restoring this amp is a pain especially when you need to hunt down obsolete spares.

Cost involved with customs charges will burn a hole in your pocket, it would easily range between 30k till 1lakh depending on the complexity of work and the spares that one needs to change. Calculating a net effective customs charge of 40% on Product cost + Shipping cost.

I have seen these amplifiers sell for exorbitant prices in-spite of being in bad shape to buy them or not is once choice .

My 2 Cents !!.
Incredible amount of effort put into the restoration. Only passionate people can have patience and will to do so, for most will consider this to be too far gone to attempt rectification of this level. Congratulations and salutations for doing so and sharing your experience with other fm's. Do you have a background in such or do so only as a hobby? Asking as people of your expertise are slowly disappearing from the scenes these days :(
 

vinothkumar

Active Member
Joined
Jan 27, 2015
Messages
590
Points
43
Location
Chennai
Incredible amount of effort put into the restoration. Only passionate people can have patience and will to do so, for most will consider this to be too far gone to attempt rectification of this level. Congratulations and salutations for doing so and sharing your experience with other fm's. Do you have a background in such or do so only as a hobby? Asking as people of your expertise are slowly disappearing from the scenes these days :(
Santhosh is neither a dealer nor a service guy. This guy has much patience when it comes to do these things. He is truly passionate about hifi and research of his own. On top of everything he is just a software engineer and works in IT industry.
 

Kannan

Well-Known Member
Joined
Jan 13, 2008
Messages
1,434
Points
113
Location
Chennai
@mpasanthosh ........He is a total geek. What he has posted here with the restoration of the X-11 is not even 10% of the massive work he has undertaken.
Simply put after restoration, the amp sounds absolutely brilliant and flawless.
 

sunilj

Active Member
Joined
Aug 10, 2011
Messages
223
Points
43
Location
Bangalore
Nicely documented mpasanthosh. Real nice.

Please continue with pics, which is not something we see too often here.
 
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