First, some background information:
MiC 96K and Jam 96K use a proprietary connector called Hirose.
Both products would have come with a Hirose to USB-A cable (picture below).
This cable allows MiC 96K and Jam 96K to be connected to any USB-A-equipped Mac.
To connect MiC 96K and Jam 96K to USB-C equipped Mac, use the cable above in combination with Apple's USB to USB-C adapter (pictures below)
Note: The Hirose to Lightning cable will not work in this instance since it's designed specifically for iPhone/iPad that use Lightning connector.