Hi There Mike.
What additional piece of are you referring to? I just bought the M310 and it is amazing! . I'm using it with a Sony UWP Plug ( Don't judge me) and for some reason there is a slight "warble" in the sound If I push the gain on very soft Dialogue. This does not happen on any of my other cheaper microphones. is it a 48V wiring problem of some sort you think? Let me know your thoughts.