audio jack + earplug wire = 3 cables + no voltage

[linningck]

First, I am new and it is a first post, thus: Hello everyone
I would like to use my mobile audio jack, connect it to an amplifier and to speakers. Easy to say~~ first thing wrong.
When i cut the ear plug cable, i get three wires. But, I get absolutely no signal from these 3 cables. I tried them 2 by 2 and nothing. Mobile detects the plug, mobile reads the sound but no signal out of the wires before I even connected them to an amplifier.
Is it normal ? what should I do ? even starting back from step one. What's wrong.

Thank you

 

[davenn]

hi there
welcome to EP

show us a photo of what you have done

 

[linningck]

It is OK. Thank you. I was on a business trip and I get a flash ! Don't ask me how I get it. I forgot to scratch wires with sandpaper to remove the protection... This part is done.
But I still have many questions
Thank you for your welcome.