Freq and Res pot for Ghost Dance filter?

[acidblue]

Hi There.
Title says it all.
Would the Resonate pot come after the 0.0015uF cap?
Not sure where to put a pot for frequency sweep, possibly
for the variable resistor?

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[Top Top]

I'll say I did try adding a resonance pot to this design, but gave up after a little bit.

You can check here for the info I was given when I asked on another board:

http://www.diystompboxes.com/smfforum/forums.html?topic=84516.0

Yes, the frequency pot is that "VR" to ground.

[acidblue]

Thanks Top.
Strangely enough I did pretty much the same as you, I used a .01 cap instead of
the .0015 and used a 470 pf cap, just don't have any 680pf atm,

I added a 10k pot for the VR and a 5k one after the .01,(.0015) cap.
This seems to act like a coarse and fine tune for frequency.
But sometimes when turned low or high I think I can hear a change in Resonance.
Although I could be wrong.

Gonna experiment a little more and see.

[Top Top]

[synthmonger]

You could also replace the VR with a current sink using a 2n3904. This will allow voltage control and you could tune the cut off frequency range quite a bit better.

I'd suggest using two more inverters as amplifiers with a feedback path going from output to input if for your resonance control.