Sansui AU-101 - bias adjustment?

i remember NAD doing that in early versions . the resistors were there already and you had to remove a link .then take reading across drivers emitter resistor .
you have 2 choices here and easy one is check / set by measuring current across empty fuse holder . other is fit emitter resistors and see how it sounds afterwards .
 
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Thanks, I went with the easy option :) I got a bias current ranging from 8.70mA to 9.0mA. As mentioned, even if I increase the resistance of the trimpots to the max I don't seem to be able to get a bias current of 20mA.
I have been wondering about fitting emitter resistors and if not having any at the moment could be the reason why I can't get a bias current of 20mA. I guess that would be a nice experiment to conduct once I am done recapping my Sansui AU 555.
 
On both the AU-101's I had there wasn't any bias adjustment pots, bias was fixed around 9-10mA and the pots fitted were for adjusting the output balance, setting the voltage on the output caps to half supply voltage.
 
I had a similar issue on this amp. The problem was a dry solder for one resistor on the power amp board.

Agree that it probably would be good to change the flying saucer transistors regardless. I had another issue with the bias current fluctuating a lot which got resolved when I replaced them.
 
Re the intermittent crackle, all of the small signal transistors are known noise makers, and should be replaced if pops or cracked are present. There are some suggested replacements in the thread I linked above.

The 101 is a great littelmamp when working correctly

Cheers

John
 
Thanks, I went with the easy option :) I got a bias current ranging from 8.70mA to 9.0mA. As mentioned, even if I increase the resistance of the trimpots to the max I don't seem to be able to get a bias current of 20mA.
I have been wondering about fitting emitter resistors and if not having any at the moment could be the reason why I can't get a bias current of 20mA. I guess that would be a nice experiment to conduct once I am done recapping my Sansui AU 555.
Ok, that's actually not right. I was measuring the bias incorrectly. It turns out that I can definitely get a bias of 20mA. At that level the amp seems to be performing fine.
 
Ok, that's actually not right. I was measuring the bias incorrectly. It turns out that I can definitely get a bias of 20mA. At that level the amp seems to be performing fine.
Hi Jedlejedi. I know this is an old thread. I am trying to set the correct bias after I completed the recap. But I could not get the 20mA across the empty fuse holder. I am only getting 4.5mA max on both channels. Mine is the later version of the au 101 that has the wire links. I would really appreciate it if you could let me know how to properly set the bias. Do I have to install an emitter resistors replacing the wire links? Here is the photo of the main amp. Thanks in advance. 20240313_181013.jpg
 
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