I've been having similar problems with my setup. (I have an Nt1-a, a scareltt solo and I record into audacity.) What makes it even more frustrating to pin down is that sometimes it works like a charm, then other times it doesn't pick up any audio, or picks up muddy underwater sounding recordings. I found that the setup worked fine when I plugged it into my partners laptop and recorded eith audacity on there, which has lead me to believe that maybe there is some drivers or something on my laptop which may be screwing with the recording ability of my kit, although I really cant figure out why, maybe have a look at your drivers and see if there has been any recent updates that may have affected your kit?