Audio Input issues with Traktor S4 audio interface

[Jip]

Hi - I'm experiencing some difficulties using the Traktor S4's audio inputs effectively to route audio from the Korg Monotribe into Ableton.

If I use input D (with the gain control), nothing registers in Ableton...... is there a setting to make this work?

If I use input C (no gain control) when switched to Line the audio picked up by Ableton is extremely quiet (even with Monotribes vol at full)

If I use C with input setting on phono - it sounds nice and loud - but is maxing out the input on Ableton into the red, making recording distorted, unless I switch the Korgs volume right down, which then makes the input behave but the sound is weak as the Korg is running at minimal volume.

Can I route input D on the S4 into Ableton? Giving me a the gain knob to adjust levels, or is the problem with Ableton?

Any help with setting up the S4 as a viable audio interface with Ableton would be much appreciated.

Many thanks