Hello, I am a beginner on recording. I bought a Behringer UB802 for basic mixing, I tryed to record my voice to the computer with Phantom powered microphone, but I am having a lot of deep noise. Even if I unplug the microphone and everything it's still there. if I volume up the mixer it's getting really bad. what can I do about that. do you guys thing the mixer doesn't work properly? my friend said try hum eleminators but it shouldn't be the reason, because there is no microfon or instrument plugged yet. I also tryed 3 different computer for make sure, but all of them has the same noise. thank you for your responds.