External USB DAC not working

this topic was discussed in same threads earlier but without solution.

I‘m running a PI3B+ with current Version of Volumio. The external DAC is a Pre Box S2 digital and should be supported.

My problem is, that it seems that the USB Ports on my PI are not active.

In the configuration of Volumio, I couldn‘t find any option to activate USB Ports. The only options are: headphone, HDMI or the DAC hat. I turned I2S DAC OFF and activated headphones. The Headphone jack on the PI is working properly.

But the USB DAC doesn‘t get any power. As I know the issue with PI3B+ and USB Power, I gave the USB DAC‘s its own power unit. The DAC is now running so far but without any sound.

How can I activate the USB Ports?


The USB ports will be working (active), but your DAC is not being recognised for some reason. Is it seen as a usb device (lsub), and what does ‘aplay -l’ and ‘aplay -L’ show. Is it present in ‘alsamixer’?