If detected will a DAC connected by USB appear as a “new” listing or do you have to guess at what the closest thing is that might be compatible?
a USB DAC has nothing to do with i2s. Turn i2s off and select your USB DAC
Interesting, thanks. I can swear I came across another (recent) post here where it said to turn I2S off, plug in USB DAC, reboot, Turn I2C On and select it from there. That’s probably why none of the DACs I was trying didn’t “show up”…
Have the RPi4 working with DAC2 (as DAC-Plus) and Line Out functions.
Wanted to test my new SMSL DAC/AMP as it is my preferred end use device for the project (just got it today and a week+ of Amazon delays).
Setup the SMSL, plugged it into the RPi4, rebooted.
It shows up like above. Selected it (I2S is OFF). No sound. Rebooted and cold shutdown/restart, same thing.
Do I need to physically remove the HiFiBerry and try again or remove it and start from scratch on a vanilla install with the SMSL attached?
UPDATE: For grins I installed a fresh vanilla Volumio with nothing on my Pi5, not even a display and connected it to the SMSL. Detected but no sound. Guessing it’s not supported?
http://logs.volumio.org/volumio/wSoiLO5.html
Updated Pi5 to Test image (3.742) and rebooted. No joy.
http://logs.volumio.org/volumio/OU9hiDA.html
https://www.smsl-audio.com/portal/product/detail/id/867.html
Volume Options:
First try changing the settings to NONE in Mixer Type. Next try software (remember to change the song playing to the next one each time you change)
NO
That didn’t do it but by tinkering with other settings (something that got me into a lot of trouble previously 
) the trick is to change Default Starting Volume to 100 and Max Volume Level to 100.
I don’t understand why but it works with every DAC I tried, including dongles. But now I know.
Thanks!