Have you given Audacity permission to use the USB DAC? (See: https://forum.audacityteam.org/t/no-signal-from-usb-turntable-mojave-solved/50763/6)
Have you given Audacity permission to use the USB DAC? (See: https://forum.audacityteam.org/t/no-signal-from-usb-turntable-mojave-solved/50763/6)