Restoration/Upgrade Of Scribby31's Sansui AU-9500

hi everyone and sorry to bring up this old post.
I have an au9500 and am preparing parts to do a full restoration .

Reading here and there I understood that it would be a good thing to change also the bridge rectifiers working on the 4 big capacitors
Reason is that they are prone to fail.
Do you have any experience with this?
Which part should I buy to replace them? (Usually sourcing from mouser)

Other question
Leestereo mentions ksa1845 as transistor replacement but I do find only ksc1845
Are they the same or interchangeable ?


Thanks a lot !
The stock the bridge rectifier in the AU-9500 is quite common in other units and I have not found them to be particularly failure-prone. The 2SA726 is replaced with KSA992; the 2SC1313 is replaced with the KSC1845 (in post #39, Pilsern mistakenly refers to KSA1845).
 
The stock the bridge rectifier in the AU-9500 is quite common in other units and I have not found them to be particularly failure-prone. The 2SA726 is replaced with KSA992; the 2SC1313 is replaced with the KSC1845 (in post #39, Pilsern mistakenly refers to KSA1845).

Thanks Leestereo

I red that the higher capacitance of the 4 filter cap will put the bridge rectifiers under stress (at unit switch on)
But good to hear that you haven’t experienced these parts to be failure prone

Another question, maybe a stupid one:
Willing to replace the 4 big filter caps I am looking for some 10000uf 63v with 40mm diameter to place them properly in the clamps.

Nichicon KG seem to be the right choice but they are out of stock in the main online shops.
Would it be safe to replace them with some 10000uf 100v units?
Is the higher voltage ok?
 
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i have another question for the experts
let me know if is fine continuing writing here or if i shall open another thread.....

now, about the question:
checking the power board f2030 i found a diode(?) "ZD052" that have been replaced
I wonder which would be the correct replacement for it
on the Sansui manual it says 1N721A

I want to be sure that it has been replaced with the good one or eventually changing it

thanks
 
The schematic for F-2030-1 lists EQA01-20R (see post #2), which is a 20V zener, as is 1N721A, but the latter is rated at 250mW whereas the EQA01-20R is rated at 500mW. It would be prudent to install a 500mW zener (e.g., BZX55B20-TR)
 
Its an old thread but id barge in for a query . My amp has 10k filter caps now . And am very happy with the sound after a thorough job of recapping it.
Would i endanger anything or blow up while cranking it up any day of the week as the rectifiers are both unchanged originals?
I normally play well below half a watt.
 
Its an old thread but id barge in for a query . My amp has 10k filter caps now . And am very happy with the sound after a thorough job of recapping it.
Would i endanger anything or blow up while cranking it up any day of the week as the rectifiers are both unchanged originals?
I normally play well below half a watt.
No.
 
Aloha
find this homemade Sansui Au-9500 Clone somewhere in Japan don't know about the modification but it really sound wonderful with JBL 4311B or other good speakers
actually thought to sell the but Amp after a listing session i change my mind I'll keep this thing
Cheers:beerchug:
IMG_20190728_162137.jpg IMG_20190728_161957.jpg IMG_20190728_162158.jpg IMG_20190728_162305.jpg
IMG_20190728_162158.jpg
 
Its been almost 4 years since Scribby31's AU-9500 was restored/upgraded and AFAIK, it hasn't missed a beat with the original rectifiers in place.

Hi, I just bought an au9500, the sound was okay but my Sansui 8 Deluxe sounded way better and more detailed. I'm not sure if my au9500 has been recapped or if it's still all original, I took pics and would like to share but somehow I can't upload the pics on this thread, I can email pictures if you like.

I'm thinking about recapping the au9500 (not sure if mine has been recapped) since i'm not very pleased with the sound. I saw this site selling an upgrade kit for €39.00 ($46usd):
https://www.audio-high-store.com/product/sansui-au-9500-upgrade-kit-audio-capacitors/

Is this a good deal? Are these the only capacitors that need to be replaced for the sound to improve?

Do I need to get these as well:
https://www.audio-high-store.com/product/nichicon-lkg-4700uf-63v-snap-in/

Hope to hear from you guys soon!
Keep safe and TIA!
 
These capacitor kits are not thought by me at least, to be the best way to re-cap your pride and joy, better to buy 'known genuine' capacitors from recognised suppliers like Mouser, Digikey, Farnell, etc

BTW: please do not revive old threads - especially with duplicate posts.
 
Hi guys, apologies to comment on quite an old thread.
Just done a complete overhaul on my au 9500 and followed this one exactly as it was very precise and had all parts listed, thanks in advance.

I have switched the amplifier on and something is not right. Zero sound before quarter of a turn and then terrible quiet scratchy sounding music after that. Both channels are the same.

I’m no expert but I’m decent with a soldering iron and have double checked everything after, including the transistor replacements ECB order etc.

now I’m wondering if mouser have sent me the wrong transistors,
I ordered KSA992FATA which is what it states on the paperwork with the order. On closer inspection the transistors have written on them JCA992FA.
Are these the same things? Could this be the issue here or does anyone have any other ideas. Long shot I know but I’m struggling a bit here
 
JCA992FA.
Are these the same things?
You'd better contact Mouser, as I have never heard of them, but more to the point neither has the whole of the Internet! - enter the type number in search and hit enter... NO hits at all. :idea:

Is it written on one line, or like this:-
JC
A992FA​

If it is like the above I think you have the right device.
 
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...I have switched the amplifier on and something is not right. Zero sound before quarter of a turn and then terrible quiet scratchy sounding music after that. Both channels are the same...

Use the preamp in and main out jacks to connect an external amplifier and external preamp, respectively, to determine if the issue lies in the AU-9500 preamp stage or power amp stage.
 
Hi leestereo, thanks for the respose. got to the bottom of it eventually. i had two local decoupling caps for both the driver and output stages round the wrong way, reversed the polarity on them and and changed two of the fuses on the back and now i have sound on both channels.
however, after some listening sessions the bass and treble and highs are great but the midrange is quite quiet in comparison and vocals just seem a bit dampened and no longer crisp and loud.

i followed your restoration closely and used all the same values of caps that were stated. mainly using nichicon for the power supply, wima and panasonic for the films and panasonic for the other low esr electrolytics. looking by the pictures i pretty much used the same caps.

my follow up question is, what do you think could be causing my lack of midrange and vocals? do you think i have blown something else apart from the fuses with the reversed caps? or am i just hearing what its supposed to be like after recapping? i think not.

i have recapped a sansui 9090 before and just did the caps but used exactly the same values and had terrific results, the thing absolutely sings.(sounds a lot better than the 9500 atm)

where would you start with the lack of midrange issue do you think?

many thanks for your responses in advance.
 
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