I just purchased LP-16 and right out of the box in “usb interface mode” it produces crackling noise from outputs when nothing even plugged into the input stereo jacks. Upgraded to the newest firmware in hope that it starts working properly but no results. The same crackling noise still present.
I think I identified the problem. It is probably faulty USB cable that was supplied with the unit. I am not 100% sure yet as I don’t have a spare USB cable at the place I am right now. But, I have a short quality USB extension connector. When I plug that black usb cable into that extension and then into computer the crackles go away and the sound is clear. Not really sure what the miracle this connector do, but the result is clear sound 🙂