Hello. I have a problem where my headphones switches to mono when connected to audio interface through 6, 3mm jack. It works fine when I use 3, 5mm jack with 6, 5mm adapter. But for some reason when I use 6, 5mm wire, ?which was included with headphones, it doesn't work in stereo. I have: Sennheiser hd 569 headphones, Behringer UMC202HD interface, OS linux