For anyone who has found the microphone input is not working:
macOS Mojave (10.14) has introduced new features under System Preferences -> Security & Privacy -> Privacy tab where microphone access permission can be given to each application individually. However, EchoHam actually needs to request microphone permission and this request was first included in V2.06 released 26 June 2019.
So, if you experience the microphone problem, make sure you are running EchoHam 2.06 or later and that EchoHam is ticked in the Privacy tab.
Further reading in this apple article:
https://support.apple.com/en-au/HT209175