Can the distortion detector be plugged in to the speaker outputs along with the speakers to monitor when the amp starts distorting while playing music?
I can't be positive on this but my dd1 only works properly when it's given a 1k Hz or a 40 Hz note. So if your music doesn't produce this tones then it won't work and even then a split second probably won't read or give you long enough to knowing it's clipping or not.