Sansui AU-101 amplifier

General:

Sansui Japan made this amp in the 1970's, a low to medium power amplifier.
It is similar to Sansui amps as the AU222, AU505 and the AU2200.
 

 

Special futures:

This amp has the traditional Sansui look and the same quality as all the Sansui gear.

 

Schematic:

Click here to download the service manual of the Sansui AU 101 amplifier

 

 

Modifications:

As you can see at the pictures I have changed the speaker connectors, as these were broken.
Replaced are all electrolytic capacitors in the amp and added 1 capacitor on the power supply,
there are now 2x 6800 uF 50V and new diodes in the supply.
I have added several capacitors in the power rail of the pre-amp. Also changed the caps at the input of the main amp.
The final transistors 2SC1060 were broken and replaced by Sankens 2SC2577. Giving the amp more power, approx 2x25 Watts.
You may also replace for TO-66 transistors, as initially the whole design was around a set of TO-66 power transistors,
as you can see by the hole design and drilling of Sansui in the pcb and the heatsink, like the 2SD255 or 2SD315 is a good alternative.
The sound of the amp after the modifications is very much improved and much more stable lows are in the sound.
It can drive bigger speakers now.
As much more amplifiers in this time frame, the whole setup of the pre-amp section of this Sansui amp can be changed more radical to more modern standards, as I describe in the article about the Monrach amp on this website, read it here: http://www.hilberink.nl/codehans/luxman66.htm
 

Here the updated pcb, the new transistors need new insulators and new heatsink grease. The Sankens do not get overheated and have better power-temperature ratings.
 

Below original pcb with original Hitachi 2SC1060 power transistors, these get so hot at higher power levels that they break down and need to be replaced:

 

Sound:

The sound quality is similar to the other AU series of Sansui, so very good.

 

© Hans Hilberink - PE1MMK ® 2003 - Last update: 11-08-2019.