Thank you mike.
Sorry for the blurry image ;(. I configured the software for read the analog A0, the output im reading is the last amplifier (from Left to Rigth), that phase agregates a DC necesary for send the signal away of negatives values. I measured other voltages sucesfully with the arduino(For examplo the sources voltages), but reading the output of the opamp is a problem :(. What do you think i can do?, can i use other device that "regulates" the voltage of the arduino? may i "couple the impedances" ?. What do you think? 
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Thank you.
Dgarizado.