SOLVED: I borrowed another working 212R to make some cross tests and it turns out that the distortion depends on bad speakers (both of them). I had them tested in first place, but I didn't realize they are bad (lack of experience). I feel so stupid
Thanks for your precious support <3)
PS: I ordered a low cost function generator and an oscilloscope because I would like to keep up with this hobby
Thanks for your precious support <3)
PS: I ordered a low cost function generator and an oscilloscope because I would like to keep up with this hobby