[sdiy] Ray Wilson Filter question

[harrybissell]

Change R11 also, to keep the voltage at IC1-A pin 3 the same...

You see the 100K / 1K dividers on the input of the LM13600/700 ?
I would add a 1K in seires with the other input to ground (instead of directly

to ground) Thiswill add keeping the DC level constant and reduce CV
breakthrough
(thump)   Adding a 1M resistor to this input (ie 1M / 1K divider) will allow
you to add
a trimming voltage to reduce the DC offset as well !   From my experience, you
need only
add the trimmer to one stage.

H^) harry

synth at oldmail.charlielamm.com wrote:

> I am trying to use this Ray Wilson filter in something I am building:
>
> http://www.musicfromouterspace.com/analogsynth/statevariablefilter.html
>
> I am using +/- 15V instead of +/- 12V.
>
> I am also using mod CV of 0 to 5V--the circuit looks to me like it expects
> 0-10V for a good sounding filter freq sweep?
>
> To make this work, I think I need to change R6 to about 47K for the 0-5V
> CV for freq mod, and R14 to about 180K to accommodate the greater supply
> V's.  I can't think of any other mod necessary.
>
> Can anyone else?  Are my subs OK?
>
> Thanks in advance for any help.  --Charlie Lamm