So I finally decided to start modding a DMG. I installed a prosound mod and the sound is much better, no noise, but it's really not as loud as the original one. I checked again the tutorials I followed and I seem to have done everything ok. I don't know much about this stuff but I thought it might be caused by bad soldering (since I'm not so good at that). Both left and right channels are working fine though so I guess all wires are connected, but the sound is so quiet.
It's a prosound mod from nonfinite electronics, installed with the wires they provided. So would that be caused by bad soldering? Bad wires? A problem with the prosound itself?