Sansui AU-5900

The end stage of this amplifier is easily to upgrade to the end stage of the AU7900. You mis some controls you never use. I worked in the Netherlands for the importer in the 70's as a student and they did it for some discothèques. The only problem are the power transistors, which are hard to get in Europe now adays, I ordered mine in Hong Kong and got 5 pair of paired ones of the same brand and type as the originals.. I refurbished mine bought in 1976 the capacitors are easy to get and I repaired at the same time some weak points. Easy to say I have degree in electronics. The now drive my Sonus Faber Lumina III loudspeakers, which give a real good sound.
The mother board of the au5900. au 6900 and au 7900 are the same, so you have only to add or replace some components .