Having slept on the problem, there is a better way to get best volume on a 3V supply. Don't try this on a 9V supply as the current through the transistor will be too great.

 

Hi,
ok, thanks i'll do it and keep you up to date if you want !

 

I don't like the 10 ohm resistor. This is how I would do it. Note that this drive circuit works best at higher power supply voltages. It works very poorly at 3 volts.

 

This is a Classe B amplifier isn't it?

 

Indeed it is.

 

It's funny, because that how they made it on the original circuit !
https://www.dropbox.com/s/eq3n1kzuco1qcpl/aze.png?dl=0