I read from somewhere that you just plug in an FC7 in foot controller2 and it will control the superknob.
I have an FC9 and I tried several combinations (FC9's OUTPUT1/FC9's OUTPUT2 to MODX foot controller1/MODX foot controller2 in both, CV and Normal mode) and it will not control it.
I even tried brand new batteries on the FC9.
I never tried the INPUTs for the FC9 as it does not make sense (unless I am thinking about it wrong).
I am using a stereo cable for some headphones I have with 1/4" adapters. I am willing to buy the cable too if necessary. 🙂
The FC9 is a volume pedal that has been discontinued for quite sometime. The FC7 is a foot controller that is quite different than an FC9 and I'm not sure the voltage is the same.
Anyway, the FC9 will not work with MODX: Only the FC7.