Cgs synth

>Hey all / Ken: An idea that I had last night, trying to get to sleep:
>
>Could I replace the 100k Bandwidth pot(s - in my case, not having a
>dual 100k), as well as the 50k pot for the Damper - with VCAs? I have
>5 Ken Stone / René Schmitz VCAs spare at the moment, and thought of
>that idea last night - as I'd love to have voltage control over both
>functions. (A dual VCA for each of the Bandwidth, variable
>resistors).
>
>--
>Take care,
>Warmth and Peace,
>Ryk
>
>http://www.sdiy.org/damian/index.html - my modular synth's homepage :)
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>

On 2/21/07, Rykhaard D.A.M.I.A.N. <rykhaard@...> wrote:
> On 2/21/07, sasami@... <sasami@...> wrote:
> >
> > Damper is a voltage divider, but I see no reason why a VCA wouldn't work
> > in this position anyway.
> >
> > Ken
> >
> > >Taking VCA and BInTic schenmatics to work with me right now. As
> remembered
> > >that Bandwidth are current limitingh reissitors and the Damper one is a
> > >voltage divider., Correct me if I'm wrong. Will check email at work,
> > >whilst studying schematics to mix the two. :)
> > >
> > >Thanks!
> > >
>
> The Damper position with it dividing between Output and Ground and my lack
> of experience within these regards, were my greatest curiosity. :)
> Thank you much! I'll be trying each of the sections out tomorrow, with the
> 1 VCA from you / René that I have completed. If tests / any required
> adjustments that I can comprehend bring it all up to working, I'll add the 3
> x VCAs to it and post a full report with samples, to my webpage. :)

And here I am with the results, verbally. :) :)

- I disconnected my 100k Lin Alpha Damper pot (Ground, Out, In as seen
from the back)
- connected the pot input to the Ken / René VCA Input
- connected the pot output to the VCA Output

Initially - +/- 2.5VDC Sinewave LFO output had no effect at all. So I
figured a +/-7VDC LFO Squarewave output (Yeah - I still have to fix
it's output format.) should possibly provide more impact. It had
barely any effect in place of the 50k Lin that's supposed to be used.
I hooked up the 100k Lin Damper pot again, and the BiNTic was still
operating fine. Next:

- I disconnected my 2nd 100k Lin Alpha Bandwidth pot (having no dual 100ks)
- Turning up the VCA's Initial Level control had a very good IMMEDIATE
effect! :)
- Hooking up the Sinewave output to CV1 input on the BiNTic worked
wonderfully as well
- Hooking up the Squarewave output to CV1 input worked even better
- All related controls worked beautifully over their full ranges. :)

I'll post samples to my webpage along with a report on the dual VCA
addition to the BiNTic (1 VCA for each of the 100k Bandwidth Controls)
once it's all completed.

The BiNTic itself is one helluva scary (on a good way) module in the
first place! With CV Inputs for Pitch and Lin FM. But now CVs for
each of the Bandwidth controls (via dedicated VCAs)? Woohoo! :D

I'd like to know in electronics theory, why the VCA wouldn't work in
place of the voltage divider Damper pot. (Not enough electronics
theory knowledge yet. :( )

As far as I'm able to comprehend, the VCA works wonderfully in place
of a variable current limiting resistor. But it's not working in
place of a variable voltage divider. :( For it to work properly,
would I have to use 2 x VCAs, with polar opposite CVs to each of them,
to work as an equivalent pot? Each limiting the current in opposite
ways? As far as I can understand so far - that should work.

I've only got 5 x Ken / René VCAs at the moment though and 3 more
needed to complete a 4 x VCA panel, so I'll stick with adding the 2 to
the BiNTic and the put the other 3 in the VCA panel. I'm happy enough
now with the way this BiNTic modification is working. :)

Thanks again Ken, René and Jan (wherever you are :) ) for the work on
both of the modules! :D:D Happy happy, joy joy. ;)

--
Take care,
Warmth and Peace,
Ryk

http://www.sdiy.org/damian/index.html - my modular synth's homepage :)