[sdiy] very simple vco

[Scott Gravenhorst]

"Mike Brown" <mike at electronium.com> wrote:
>> But as pointed out in another posting...it is the expo converter that
>> makes the VCO's complicated.
>
>OK... here's where a simpleton like me can help out.
>
>Keep in mind, Luca asked about "a simple, almost primordial VCO", not a
>"musically useful" VCO (or what the more advanced members of this community
>would consider "useful").
>
>I was in the same situation when I set out to build my suitcase synth
>project.  I had wanted to get started with DIY for years, but was daunted by
>the apparent complexity of most of the circuits.  (I later found that they
>weren't as complicated as I thought ; )
>
>I would highly recommend to someone in Luca's position to go ahead & build a
>simple linear VCO to play around with... I've had great fun with mine!  just
>the experience of building a circuit that made noise has spurred me on to
>want to build more advanced circuits!  while there are certainly limitations
>to the linear vs. exponential design, none of that really matters until you
>build more modules anyway... ; )
>
>Thanks for the soapbox.
>
>Mike

True enough and in most cases, if not all, an expo converter can be
retrofitted to any linear VCO and vice versa.  I use linear anyway, and many
circuits I've seen have an expo converter...  I needed to replace the expo
converter with a linear V-I circuit.

Personally, I think René Schmitz's VCO4069 is about as simple as it gets. 
And very inexpensive! (Luca said he's a student, so this may matter).  It's a
VCO which is quite musically accurate and has a very wide range, I got 9
octaves and stopped testing, others have seen it do several more than 9.



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