Extremely noises on on left output

I have a big problem.
yesterday i was playing on a gig over a large PA. We discovered that my left output has extremely rushed from beat buddy from a certain gain on mixer. My current wiring is “output left drums” and “output right bass”.
On right output everything was okay. I added 2 links to mp3 files where i raised the gain of the mixer in the middle of file of its extremely.
There you can hear the extreme noise increase (Output left) when increasing the gain of the mixer.
The right output is seen to that anything will be distorted but the noise is not so extreme increases as the right output.

I hope my englisch is good enaugh to make my problem clear.

Can anyone help me to solve this problem?

https://www.dropbox.com/s/qc4an0q643sqnmj/Beatbuddy Drums.mp3?dl=0
https://www.dropbox.com/s/4dtrifoi296wtdp/Beatbuddy Bass.mp3?dl=0


I found out something out.
When i connect a passive di-box (Palmer PAN04) on the left output channel and hit the groundlift switch i only hear the extreme noises when the gain knob of the mixer is at 90% of its range.

Does that help to find the problem?


nobody here who can help me?