NE Viol Ruina question (maybe obvious)

Hi,
I've been using modular hardware for a while, and I'm experimenting with this NE filter/distortion.
My question comes with the Mod (modulation) switch.
I have read the manual but I don't quite understand it.
The manual says:
//Mod: The audio is routed back to the filter cutoff frequency for
input-dependent FM. Down position is off, middle is mild, high is
extreme//
I'm intrigued, because if I output the audio through the filter output, without going through the distortion circuit (Mangle) I get the oscillator signal (SQR) very attenuated and low in volume.
I am modulating the cutoff frequency with an attenuated EG via a triatt, since the CV input of the filter accepts 0 to 5V.
I have also deactivated the automatic frequency envelope, so that only the cv that I send it from my EG affects the cut.
I already knew that this is a rather "special" filter, but I'm afraid I'm not knowing how to get its good side out.
If anyone has used it, and can help me....
Thank you

I also own a Viol Ruina. I hated it for quite some time, because it behaves strangely, most often. I had the same problems you described. And yes, the filter out is pretty low volume. You basically need the Mangle to push the level up. I had the module laying around unused for months, before I gave it another chance. And then somehow it clicked for me. Now, it's an integral part of my core setup. I mostly do parallel processing with it, as I can control the amount of crazyness it brings with it, that way. I know how to push it, to get what I want from it. But I'm sure, there's even more, as it is such a beast, in a positive way.