TomG's VCF9a

[tomg]

> > IMO, it cannot work the way it was designed.
> > Look at the loop gain around the inverting adder, noninverting integrator
> > and inverting 2nd integrator.
> > 
> > (Switch pins 13 and 14 of the 13600 and you have the familiar Oberheim
> > scheme.)
> > 
> > Strange that it's in the layout, too, so it can hardly be a typo.
> > Does anybody test these layouts before they get published ??
> > (Sorry Tom, no flames intended. But do you actually *build* all this stuff
> > yourself ?)
> > 
> > JH.
> 
> I think your opinion is wrong. I don't have time to go over it right this 
> minute, but I will. And yes I test everything before posting. I do not
> always test pcb layouts. However I always state that it was untested
> if that is the case.
> 
> I will get this out and help Jorg as soon as I can. Maybe a day or two.
> I'm trying to get the vco4 shipped today. Please be patient Jorg. It does
> work and does sound very good....I'll be back.
> 
> -tg

I didn't mean it to sound like I don't make mistakes. I do...I make a lot of
them. I try hard not to but....Someone once said "If you are not making
mistakes you are not doing anything, it's the only way to avoid them."

I console myself with that all the time. I tend to do a lot of stuff so that
naturally leads to a lot of mistakes. I hope less and less over time, but
I'm still working on that zero mistake state!!!

As far as the the pins on the ota being switched I remember doing that
on purpose, because it worked better??? I think it's the way the ms20 
is configured. There may be something else wrong but I won't know until 
I look..  So I be back in a little and we'll know.

-tg