LP-16 as Mac audio interface problem – frgrainy sound

Hi,

Please tell me the firmware version on your device. (you can check that where you turn on the device it shows a 4 or 5 digit number on the screen)
Some user experienced that problem with long USB cables. Please try with one another USB cable or/and try to connect to different port on your computer.
Do you have a same problem on 44.1/48kHz? It is a same issue on both two sample rate?