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AU-D707 (AU-819) restoration

jwc2012

jwc2012

Active Member
I finally had my AU-D707 (Japanese domestic version of the AU-819) refurbished. It turns out that many of the components were in awful shape, and that my decision to pull it from service when it started running hotter was correct. One notable finding was that many of the caps that looked fine from above were in an advanced state of corrosion below—probably due to the infamous glue. I found a good local tech who has extensive Sansui experience, so I didn’t run the added risk and expense of shipping.

I thought the folks here might be interested in the pictures my tech Javier posted of his work (and the scary condition of the caps):
https://www.instagram.com/p/B3zxcmhJsED/
https://www.instagram.com/p/B3zzXWgpDLO/
https://www.instagram.com/p/B32tQaiJmP1/https://www.instagram.com/p/B32uWyNpj-3/

I'm shocked at how good this amp sounded despite the degraded state of so many of its components. It now sounds wonderful and remains much cooler regardless of how hard I drive it. It is now ready to play beautifully for many years to come.
 
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Really great restoration work - those "Black flags" really have the look of being past their "sell-by-date"
 
AUD101 said:
Really great restoration work - those "Black flags" really have the look of being past their "sell-by-date"
Click to expand...

Yeah, they looked like a disaster waiting to happen. Even some of the resisters looked pretty shot. Made me wonder if a prior owner had been running this 100v model at 120v.
 
AUD101 said:
Really great restoration work - those "Black flags" really have the look of being past their "sell-by-date"
Click to expand...

Yes, I think Javier did a very nice job—and a time consuming (and therefore expensive) one. He also serviced my Luxman R-115 and replaced the protection relay. He’s very knowledgeable and a true craftsman. I was lucky to find him so close to home.
 
This restoration is money well spent - what's your initial impression on how it sounds now with regards to before etc.
 
AUD101 said:
This restoration is money well spent - what's your initial impression on how it sounds now with regards to before etc.
Click to expand...

Rather dramatic, since channels no longer cut out regularly—though that was due to the corroded pre-out/power-in switch. Otherwise, it is hard to state the sonic differences with any confidence because I had stopped using the amp for over a year before I had it restored. I had a series of amps filling in, including an Acurus, a NAD, an Adcom, and finally a Sansui AU-G99X. Except for the G99X, I thought the unrestored AU-D707 was clearly better. I prefer the restored AU-D707 to the G99X (and the latter is a superb amp).

If I had to compare the before and after, I'd say the difference is surprisingly subtle and that the restored amp sounds slightly more refined and therefore somewhat more detailed with sharper imaging. That’s why I was surprised at how good it sounded before.

The most important difference, however, is that I have an amp that is no longer in imminent danger of blowing its irreplaceable output transistors. I've listened to quite a wide variety of high quality gear, and I've never heard an amp I liked more. So, yes, this was money very well spent. :beerchug:
 
Hi, looking for Sansui AU-D707 schematic diagram or service manual to trouble-shoot my unit.
My unit can power on but no sound.
Appreciate kind soul out here can help me.

Thank you very much.
 
Hello Peter,
Thank you very much for your link to the manual. I supposed AU-819 has the same schematic as the AU-D707?
The red light do not flicker.
Do not hear any relay click. Which relay is this and where is it? Is this the thermal relay after the amp is warmed up?
Really appreciate your kind assistance.
Thank you.
Wilfred.
 
Wilfred Kang said:
Hello Peter,
Thank you very much for your link to the manual. I supposed AU-819 has the same schematic as the AU-D707?
The red light do not flicker.
Do not hear any relay click. Which relay is this and where is it? Is this the thermal relay after the amp is warmed up?
Really appreciate your kind assistance.
Thank you.
Wilfred.
Click to expand...
The AU-819 is the international version of the Japanese Domestic market (JDM) AU-D707.
You should now start your own thread, so the expert can better assist you trouble shoot why your speaker relay didn't click.
 
Wilfred Kang said:
Hi, looking for Sansui AU-D707 schematic diagram or service manual to trouble-shoot my unit.
My unit can power on but no sound.
Appreciate kind soul out here can help me.

Thank you very much.
Click to expand...
If the relays kick in and red light isn't blinking then you need to deposit all controls and switches.
The switch on the back gives a lot of trouble!!
 
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