[Lucas Melo]

Hi Darryl, thanks for the reply.
You need not to worry, I'm not using phones plugged on the computer... I just mentioned it because I have read some replies on Forums and wanted to test if having the 2i2 as a "secondary" device would work and HOW it would work... I understand, though, that it should work properly as my I/O device, whithout the need to other conections...

Now, to your points:

Make sure the headphones volume on the 2i2 is turned up.
R: Is up, that's an easy one :)

What exact headphones do you have?
R: A cheap one. That shouldn't really be a problem though, because I can hear sounds when I'm at 48000 and even at 44100, though with crackling on the later.

Make sure the interface is not being used by Windows audio.
R: As I said, the moment I do this I stop having any audi playback.

The 2i2 has basic hardware monitoring. My suspicion is you have the 2i2 set to fully hardware monitor and you have no live mic etc input to the 2i2 and with the monitor set as you have it you are not hearing playback from the DAW, just those those live inputs with no signal.
R: I don't have much knowledge abou any of this, and I'm not quite sure if I understood what you said here... What I can say though is that I've tried plugging my guitar into the 2i2 and I can hear it with no problem, except that is Crackling... as everything else at 44100... My point really is that I started setting things up accordingly with the manufacturer tutorial and they never said anything about not using the 2i2 as default device 9which the installation procees did on its own, it was not an action form my side)... not only that, they explicitly said that I should be able to hear anything coming from the PC through the 2i2, and when I change it from default device that's no longer possible, so... I doesn't seem to me to be the solution for the problem, since it creates another one...

You need to read the product manual about hardware monitoring, and play around to understand what all this does. So hopefully you have a mic handy to play with.

If you cannot get hardware monitoring to work, and understand how to use it to monitor live inputs and blend back in DAW output as well... then you may have a faulty 2i2 headphone output, but much more likely to be you are not understanding hardware monitoring.

I appreciate the time you took to answer this thread, but "read the manual" is not quite the answer I was expecting (I hope I don't sound too rude saying that) and was hoping that someone who had a similiar experience could give me some advice...