Hey I tried the following: make / writable. check Vendor ID and Product ID with after you have plugged in the USB DAC : dmesg | grep Vendor for me => "New USB device found, idVendor=05ac, idProduct=110a, bcdDevice=26.50" (it is a: Apple, Inc. USB-C to 3.5mm Headphone Jack Adapter) (for another product with another Vendor and Product ID icould also get another DAC work) in cd /etc/udev/rules.d create: # USB-DAC plug in ATTRS{idVendor}=="05ac", ATTRS{idProduct}=="110a", ACTION=="add", RUN+="/usr/local/bin/load_dac_module.sh" # USB-DAC unplug ATTRS{idVendor}=="05ac", ATTRS{idProduct}=="110a", ACTION=="remove", RUN+="/usr/local/bin/unload_dac_module.sh" reload udev rules: sudo systemctl daemon-reload sudo udevadm trigger check aplay -l for me: => card 1 and Device 0 in /usr/local/bin/ create the scripts: 1. /usr/local/bin/load_dac_module.sh #!/bin/bash sleep 1 sudo -u phablet pactl --server "unix:/run/user/32011/pulse/native" load-module module-alsa-sink device=hw:1,0 /usr/local/bin/unload_dac_module.sh #!/bin/bash # search for loaded module sleep 1 USER="phablet" #USERID from phablet= "32011 PULSE_SERVER="unix:/run/user/32011/pulse/native" MODULE_ID=$(sudo -u $USER pactl --server "$PULSE_SERVER" list short modules | grep module-alsa-sink | awk '{print $1}' ) # unload PulseAudio-Module , if it was loaded before if [ -n "$MODULE_ID" ]; then # pactl unload-module $MODULE_ID sleep 1 sudo -u phablet pactl --server "unix:/run/user/32011/pulse/native" unload-module $MODULE_ID fi make the files writable: sudo chmod +x /usr/local/bin/load_dac_module.sh sudo chmod +x /usr/local/bin/unload_dac_module.sh unplug USB DAC reboot (if the USB DAC was plugged at boot it seem that the DAC does not work than.) on a FP4 it took nearly 4 sec till the sound comes from the DAC Could somebody test and verify it? PS: this helped me: https://wiki.archlinux.org/title/PulseAudio/Examples#Automatically_switch_audio_to_HDMI