[sdiy] Synthancon VC-Resonance

[scottnoanh at peoplepc.com]

> No offense, but don't you want the 4700 pF going to the OUTPUT of the
> op-amps?

Yes.

>The circuit as drawn as not a Sallen Key or LPG that I have
> ever seen. If it works, you are on to something new.

That's a kind way of putting it.  It appears the filter is much more mutated
than I thought, or originally intended.   I've still got it on breadboard
(sans the Vactrols which I cobbed for the phase shifter) and, yes it's wired
as per my schematic.  It works as per my samples.

I breadboarded two LPG's in series a couple of years ago, with a resonance
loop, and scribbled down a schematic (well scribbled onto a computer).  Last
winter I grabbed that schematic, which was not....right....and breadboarded
straight from it - never checked back on the original Buchla.  This time
around, the resonance sounded much more...aggressive.  I thought, "Hmmm,
don't remember that part of it" and plodded on.  Sounded unusually neato to
my ears, but the mis-wiring was not an intentional thing (I didn't sit down
and say "I'm going to create a totally different filter.")

I better change the documentation (it not being a Sallen-Key and all), but I
guess I'll leave it the way it is...I kinda grew fond of the little guy.

> >> http://mypeoplepc.com/members/scottnoanh/birthofasynth/id17.html
>
> Oh Grant's right... that's not a Sallen-Key. That's some kind of wild new
> thing I haven't seen before.
>
> It sounds totally badass and deserves some analysis. Maybe a homework
> problem for the Fall... ;)

I'd be interested in the analysis.  Whoever figures it out can name it =0).

Scott