We got an old mixer for free. A large beast, but it was free. It turned out that if you hook a microphone directly to it, you can feel a small, electric jolt on your lips. Not good, it can even be dangerous. Enter the ART DTI. With this baby the jolts went away, and it can even to a small extent solve hum problems caused by ground loops too. I simply love this little thing, and having two separate channels means you can have two microphones instead of one connected or use it for stereo. It is also an adapter, by the way. It now is in permanent use in our rehearsal room. Maybe I'll get one more...