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Reply with quote  #1 

Hello everybody.

I just won this auction:

The seller says that this AU alpha 707DR is 100% new and never used and that he opened the original box just to take pictues.

This amp was manufactured around 1990-92.
So it is some 16-18 years old.

What can I expect when I turn it on after all this time?

Could its caps be all dried out?

I did a total recap on my vintage Kenwood KA-907 from 1979.

But if this Sansui is new and never used, it woud be a shame to rip all those fancy caps out (I heard that Sansui used only highest quality parts in those models) in order to replace them with new ones.
On the other hand, they might just look pretty on the outside, while being all dried out inside.

Does anybody have a service manual for this beast?
...Or knows how and where to check an set bias and how to adjust DC offset?! What are the original bias values?

Thanks in advance!


Reply with quote  #2 
Hi Aleksandar
All capacitors are empty so if you just switch on the amp you will have a  surge of current and the fuses will blow as a photo flash and the caps don't like it either.

You have to increase the voltage little by little beginning at 0 voltage.
If you don't have a Variac (variable AC transformer) you can build something called poor mans variac which is a lampholder in series. By changing the lamp of different wattage you will get different output voltage.

Another way is to bring your amp to a service shop and let them do it by their variac.
Reply with quote  #3 
Don't worry too much, Aleksandar...
The AU-alpha707DR is finely protected from accidents of that kind you worry about. It has relay-based protector and also "bleeder" - an resistor accross the main caps which keep empty the capacitors during off-state and also prevent bursts during turning on.

I had the mentioned amp, also NOS, and I just simply switched on. First time turning on required a bit longer protector flashing, but once it conncted the speakers - evreything was fine. I had some oher problem with 707, as described in my threads on AKs forum.
I now have the bigger Au-alpha907DR, but also these days aquired AU-alpha907MRX, which I'm currently waiting for dispatch.

Reply with quote  #4 
Hi Aleksandar,

I find new AU-alpha707DR on eBay
, but with the same subject of auction: " Sansui AU - 707 DR (alpha), Vollverstdrker, NEU + OVP" ???

I just want be sure that everithing is OK, so please be so kind and send feedback regarding experience with your eBay seler.

Thanks in advance!
BR, Andrej

PS. You can also contact me by e-mai to
Moze i na Srpskom :-)

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