So, guess I’m back with another question that might be even more stupid than the ones I’ve been asking before 
In the last weeks I’ve been using my eurorack setup mostly for processing sounds coming from external sources (non-eurorack synths like the MFB Tanzmaus or MAM MB33). So the thing I’m doing most of the time is plugging my external gear directly into a module using one of these cables. So I’m not using any specialinput module (which I probably should, but I’m a bit hesitant to spend valuable rack space for something that “boring”).
It works perfectly fine with all my modules (like Cold Mac, Three Sisters or Erbe Verb), but for some reason I cannot hear (or record) anything if I plug my external gear into W/ as described above. Is there something special about W/'s input jack that I’ve been missing?
EDIT: Okay, so after trying around a bit I figured out that the problem only occurred when using my Korg Monologue. Turns out I have to use the headphone out and not the regular output jack. Which means I should a) probably go get some sleep and b) take some time to recap the basics of how audio cables and jacks work. 
Still wondering why it worked with all other modules besides W/ though…