[LAU] USB cable with ferrite core

Hi, if I connect an active USB hub and an USB audio card by a 1.5 m USB cable, there are no xruns. If I connect the devices using a 0.5 m cable with a ferrite core [1] there's one audible xrun after the other. Technically a ferrite core affects the quality of a digital signal, but I wonder if it could be that much, that it could cause xruns. Maybe just the cable or the jacks are bad. Does anybody know more about USB cables with ferrite core and possible impact on the USB signal or other reasons that make a differences for USB cables or USB jacks? [1] https://www.reichelt.de/USB-Kabel/DELOCK-82057/3/index.html?ACTION=3&GR… Btw. the iPad now could connect to the PreSonus and shows all I/Os, but neither MIDI nor audio I/Os work, IOW I noticed the above when I tested the PreSonus in combination with the USB hub using Linux. I'll return the PreSonus and try to find another card for usage with Linux as well as with iOS. Regards, Ralf