Premier Pro Voice Over recording problem

Hello everyone. I have a problem that is driving me crazy. I can't record the voice over straight to the audio track as I did normally. Premier recognizes de micro, everything it's set as normal, I can record, but the track it's completly empty... (an audio .wav it's created but with any sound). All the settings in the Mac and Premier seems to be ok, but there is no sound on the tracs generated when recording.... please help. Thank's!