Alsa config

1) Make sure /etc/modprob/alsa base contain :

snd-hda-intel model=targa-2ch-dig

2) in Gnone Volume Control select :

Device : HDA Intel (Alsa mixer)
Playback : Master, PCM, Front, CD, Microphone, Int Mic around 80%
Mic Boost et Int Mic Boost around 50% (should not get any playback noise)
Nothing is muted

Recording : Capture and Capture 1 to 100%.
Nothing is muted, despite some nonsense mute icons are in red (bug ?)
Digital to 0%

Switches : Headphone ON
IE958 OFF
IE958 default PCM OFF

Options : les deux input source sur "MIC"

In Audacity, select source and playback both on "HDA 0,0".
In Twinkle, select all audios channel on "HDA 0,0 analog".