[sdiy] best soundign vco design?

[Roy J. Tellason]

On Friday 11 June 2004 11:32 pm, Scott Gravenhorst wrote:
> "Roy J. Tellason" <rtellason at blazenet.net> wrote:
> >On Friday 11 June 2004 11:02 pm, Mark Romberg wrote:
> >> what about the nat semi ICL 3038?
> >
> >I didn't know they made that part...
> >
> >> it outputs square, sine and tri simultaneously and isnt quite as hard to
> >> find as the 13600/13700. there's a decent looking schem for a VCO in the
> >> application notes that you can get from NS.
> >
> >Got a link to that app note?  I got one of these parts at Radio Shack some
> >time back and built a crude function generator around it,  but never
> > thought about using it in a VCO.
>
> I think he meant the ICL8038.

Whoops!  That's what I thought he'd said,  until I went back up there and 
looked at it just now...	:-)

> It's generally considered a crap VCO if you follow the data sheet schematics
> (the IC gets hot and it isn't very linear in response to the CV), however,
> Thomas Henry designed this 8038 VCO:
>
> http://www.midwest-analog.com/diylvco.html .

Nifty!

> It's a _linear_ VCO, not expo and is claimed to perform very well, however,
> I think it may be rather inconvenient to interface using an expo CV.  Other
> VCOs are considered better for expo.  I do linear, so one day I will try
> this, but so far, I have not found the requisite "round tuit".

I know the difference between linear and expo,  but I've also not messed with 
most of this stuff for a real long time,  probably 15-20 years now,  and I'm 
just getting back into this stuff again lately since I found this list.  Can 
you refresh my memory on which is which?  I'm used to 1V/Octave stuff,  
mostly...