You could check your Mic/Line level switch settings. Hit the invert phase buttons. attach a preamp, or you could turn up the Input gain knob on the channel input. Doing so would demonstrate the AudioBox's Self-noise feature. This handy tool adds a lovely broad spectrum hiss and 60 cycle Buzz to everything you run through it. SO, AWESOME.
Or you could take the AudioBox back to the store and exchange it for a USB Audio interface that actually works.
I had that little buzzbox for 1 day and sent it packing. It's the worst thing ever.
hope that helps!