Thank you for your suggestions, there is something better.
I don’t understand English well, communicating with you is difficult for me 
Now, I have the same problem as @bnret, in this message:
If I remove the jack plug a little, I have audio “in” working.
(This was not the case previously).
If I insert it all the way, nothing.
Does the Zynthian only work with a 6.5 jack with 3 pins (symmetrical input)?
I only have two pins on my microphone.
I set the audio in as Riban suggests:
"from main menu go into “Audio Levels”.
Find ADC Left Input and set to: “VINL2(SE) + VINL1(SE).
Repeat with similar validate for ADC Right Input.”
But it doesn’t work, nothing, no audio if the plug is completely inserted.
In addition, the settings are lost, because it does not want to save.
Indeed as soon as I return to the “Audio Level” menu it displays to me in CRTLE #2:
ADC Left Inout VINL1(SE) and for Right VINR1(SE)
It’s normal ?
For information, I have the following settings in webUI:
The V4 has a soundcard based on the same CODEC as the HifiBerry and exposes these controls by default:
Digital Left
PGA Gain Left
Digital Right
PGA Gain Right
ADC Left Input
ADC Left
ADC Right Input
ADC Right
I’m going to try to solder myself a cable like this:
http://www.techniquesduson.com/jack3xlr.pdf