Audio input to thunderbolt 3 (usb C)

[pogo22]

I'm confused. I connected my IPOD classic to the usb C port (thunderbolt 3) on my 2021 IMAC. using a 3.5mm to USB C adapter cable\.
Using settings>sound, Set my input to "USB PnP audio device"
Set output to either "IMac speakers" or "External Headphone"
when i play from the IPOD classic (or any other device with a 3.5mm jack), I see the sound inputting on the "input " but NOTHING on the output to the headphones. or IMac speakers.
Am i to assume that the thunderbolt 3 port does not entirely support regular USB functions?
do I need an external DAC to accomplish this? or what?

 

[Lifeisabeach]

Have you used this same adapter in the past successfully? Which exact adapter did you get? Do regular headphones plugged into the iPod's 3.5mm jack work?

 

[pogo22]

Yes, the adapter works fine when iPod is plugged into my phone. It is a simple 3.5mm female to a male USB C. Yes headphones and external sound unit works fine from iPod. Now, I also purchased a mini DAC that plugs into one of the USB A ports and that does not work either. I’ve also tried getting it to input to garage band with no luck. What is weird, is that on the sound screen in settings, when I try to use either of theUSB ports, I see the sound coming in, but it’s kinda grey, and I’m able to see changes in volume, but no sound on the output side.