When I close the filter and add some resonance then the low end dramatically disappears. I know that this is due to the design of the filter, but I’d like to know to what extend is it normal.
Perfectly normal. The nature of the beast. Just make sure the filter “mode” switch is not in the “highpass/Lowpass” position, resulting in a bandpass filter and not a lowpass anymore
Typical Moog ladder lowpass filter thing.
By changing the ladders capacitors to bigger ones, you get a better bass response. But the sound is then not like it is meant to be by Moog.