[sdiy] rather simple and quick VCOs

[Scott Gravenhorst]

"Ian Smith" <taciturn_unquiet at hotmail.com> wrote:
>'Allo all,
>
>I'm looking around for some quick and easy VCOs to jump start a modular 
>system. Probably a quad or more. Minimal controls. Doesn't have to be 
>1V/octave. Anyone know where to point me?

http://home1.gte.net/res0658s/fatman/VCO_pwm_tri_suboctave.html is a design I modified for linear
(that is, not 1v/oct, rather v/hz) control which was done by our own René Schmitz.  Unfortunately,
a recent computer crash and lack of proper backup caused the loss of website links I had.  René has
his version posted on his site with a 1V/oct CV input.  This is considered by many here to be a
test oscillator, but I've found it quite musically useful with a "my ear" test of more than 6
octaves of accurate tracking - that's as far as I tested it - others have tested further and posted
that it does even more octaves.  The parts should still be available and should be inexpensive. 
The only caveat is that you need to pay attention to the pin numbering, there are combinations of
gate connections for this VCO that don't work.  My schematic shows the VCO itself in heavy lines,
the rest of it is a wave shaper and other features I added.



-- ScottG

---------------------------------------------------------

-- Scott Gravenhorst
-- GateMan I - Xilinx Spartan-3E Based MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/