Hey Raziur, Glad you liked the tutorial. Not sure why the signals would fluctuate like that, to be honest. Maybe try reinstalling it to see if that changes it. As for autostarting JACK, I had to tinker around with it a lot and use the autostart jack script that I mentioned in the post. It took a bit of tinkering, and from what I’ve seen it can vary per project. Lastly, if you’re having USB issues, I would try the USB in different ports, and then try it with a different computer to see if its the device or the Pi. Could have a bad DAC possibly. Hope this helps.