SimpliSafe Video Doorbells causing buzzing / humming at doorbell chime

No, it is definitely NOT digital.  It is an analog NuTone doorbell chime from 1989.

I have spent over an hour with two different customer service folks on your help line and no one has any ideas how I can remedy the situation.  

There is a constant low hum coming from the chime unit which never happened until I installed the Simplisafe Doorbells.   It is a little annoying but not that bad when the system has not been active for a while but the noise intensifies significantly any time the doorbell is rung, or the camera is triggered either manually via the app or by motion detection.

Is the "nc connector kit" different from the "chime connector"?

As stated in the original post, I did receive the "chime connector".