USB Audio Input to Pi with DAC Output

[Ragnoraq]

I'm running a Raspberry Pi 3 running the i20220317 release and with an IQAudio DAC Pro board attached. I have a turntable that has a USB output and I am trying to get the turntable audio to play out the DAC board.
To start I created a Loopback device and set it as the output in rAudio but I am not getting any audio output from the DAC board. I'm now thinking I have to setup my own audio_output in mpd.conf but am not sure if this is correct.
I have verified that the DAC board works; I can play music files from a USB stick and I get audio out of the DAC board.
The turntable does shows up in dmesg output as USB Audio Codec when plugged in.
Does anybody have any ideas on how to make this work? Am I going to have to add my own audio_output to mpd.conf or is there something else I should do?