Xenyx 302 USB loopback/leak problem

[Bumbummen]

Hello,

 

i have recently picked up an Xenyx 302 USB and an 502 since my Razer Ultimate broke. The general idea was to use the 302USB as a Soundcard for my Headset (since it has 3,5mm and sidetone) and then mix other sources over the 502 into TR2.

This has been working fine so far except one thing: There is some leaking/loopback of the phones channel into the mic / main mix channel, even if i disable it by pressing the two black buttons into down position. The only thing the buttons change is if it is being mixed at 100% or 10% ish volume on the main mix. I cant get it to completely seperate phones and main mix.
I have read people over here prising this device as their 100% working solution, others on the other hand experience the same problem.

 

This makes the device unusable for me when using my microphone since anyone else will hear my ingame sound and their voice. Is this a  common fault of the device or should i just get it replaced? If its common, can you advise another device?
Another idea was to pickip another 302, use it as a Mic only mixer and feed its main mix into the other 302s mic line in but i feel like the device should already handle this scenario?

 

Best Regards

 

Edit: Would it even possible to connect two Xenyx 302 USB together while being connected by USB? I would assume this would create a ground loop?