I am using OSX 10.7.5 and purchased a Jensen turntable to copy my records to my computer. I plugged the USB connections from the turntable to a UBS port in my computer. However, I click record on Audacity when playing a record on the turntable nothing shows up on Audacity. I plugged in a microphone and the same thing happened, nothing.
Plug everything together and then start Audacity. Audacity checks for new connections when it starts up.
You’ll need to change Audacity to “look at” the new device. You do that with the device toolbar near the top of the Audacity work Window.
Attached is mine set up to record from my built-in microphone.