Moog Filter!

[Tadej Bozicko]

Hi all!

I have one quick question!
While trying to simulate moog ladder filter (lowpass) in spice, I noticed some weird behaviour and am now wondering if thats normal or what. The facts are:
- as control current (from exp. converter) is decreased, so is output level (at frequencies that are below cutoff). Output changes less with higher value off currents, but that gives range from 1kHz to 100kHz with original values from Minimoog filter schematic. Weird...
- as resonance is increased, the level at middle frequencies (below cutoff) decreases.
- there is always some bass-boost around 10Hz (in respect to mid frequency level)

What I would like to know is, if this behaviour is like it should be, or am I doing something wrong. The scheme is copied right since I've checked it hunded times. I've used component values as in original Minimoog filter circuit.

Tadej
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