Audacity won't work with USB or Built in microphone

Audacity 2.3.2 with Mac OS Catalina 10.15.1
I’ve used the same tape deck/behringer set up for several years with no problems but since last update Audacity will recognise both options of the USB Audio Codec or built in microphone but there doesn’t appear to be any input signal for either.
I can rule out a problem with the USB input as when checking the System preferences - Sound, you can clearly see it registering on the meter. I’ve been through options on both the Mac setting and Audacity itself, I’ve also restarted both the Mac and the program with the USB plugged and running but cannot get Audacity to register any input sound.
Any help much appreciated.

I’ve just noticed that Mac 10.15.1 Catalina is not supported by Audacity 2.3.2 so presumably this is why It won’t work any more.

Although Audacity is not officially supported on Catalina, many users have reported success with this workaround:

We are hoping to have full Catalina support in Audacity 2.4.0, which is scheduled for release in the first half of next year.