Sound acquiring using myRIO's Audio in port

[amrmesalem]

Hello
I'm using an H1C hydrophone as an input device for the myRIO i'm connecting it through a PA-4 hydrophone preamp.
yet the signal i'm getting is still too week and insensitive (amplitude of 0.8 of max 2.5V)  compared to the one i get when connecting the H1C directly to the PC mic in port.
 this is the VI i'm using

PA-4 preamp configurations 

[pauldavey]

Does it work better if you replace the brown Waveform tunnels with Shift Registers?

[amrmesalem]

Thank you for your reply No it doesn't. what confuses me most is that the preamp. has a +50 dB gain