Sansui AU-555A

General: 

This amplifier produced in the 1970’s by Sansui Japan .

 

Photos:

Front

detail back

bottom view

interior view

The restored power supply.
 

Unrestored pcb of the power amp and the heatsinked driver transistors.
 

The restored pcb of the power amp, the capacitors of the output are left as is, as they are ok for now, all other caps are replaced.

 

Special futures:

This amp was well known by audio enthousiasts as it has the mid-range tone control, very typical for this amplifier model range of Sansui.
All High quality amps of Sansui made in that time frame are equipped with mid-range tone control.

 

Schematic:

Click here to see the main schematic diagram in jpg format

Click here for the user manual of the Sansui AU555A in PDF format

 

Modifications:

All electrolytic capacitors must be replaced. The driver transistors can get quite noisy, they should be heat sinked and/or can be replaced by
modern drivers. The power amp input transistor can be replaced by a modern input transistor, a BC560C does the job ok.
The diodes of the power supply should be replaced by modern 100V 10A diodes. Coupling capacitors in the signal path should be replaced.
 

Sound:

These series of audio components soon got ledgendary by their outstanding build quality and good sound.

© Hans Hilberink - PE1MMK ® - Last update: 25-05-2010.