Low Pass Resonant Filter Question

[fishfude]

Hiya folks,

So I was building the resonant low pass filter section from the weird sound generator and I was deeply curious as to the effect of having the 470k (R35) resistor across legs 1 & 3 of the 500k resonant filter (R32), as opposed to just using a pot of half the value? (See image)



Also, I decided to just go with a 220k pot instead and it didnt seem to work, it just introduced noise when opened.

Finally, I decided not to connect leg 2 to leg 3 on any of the pots (they are acting as series resistors so I dont have to right?) and very interestingly, when I touch my finger between legs 2 and 3 of the pots I get oscillations and sonic textures. Anybody able to explain this?

Cheers,

ff

[Mongo1]

[fishfude]

Hi Gary,

Thanks for that. I managed to find out some more information on it from GEOFEX and other sources.

So, yeah, it's creating a reverse log curve for the pot with a max at ~50% the pot value.