[sdiy] VCO Pondering...

[mark verbos]

This design doesn't have any advantage over the normal trianlge core 
designs out there. In fact, it probably has more parts once the expo 
converter is added. It's linear for sure. i can't speak for the quality, 
but that system for the CV in doesn't look like it would give you a very 
semetrical waveform.

I'd say, decide if you like the idea of saw oscillator cores or triangle 
and then use one of the tried and true ones out there. This is silly 
since there's Terry's saw core and the Electronotes or Buchla triangle 
cores out there. They're just as simple, but work better. The last thing 
you need for a beginner's project are variables that nobody can warn you 
about. Terry's or the ASM-1 VCO as it's called by some is a very small 
circuit if you only have saw and square outs.


Mark



Pat Kammerer wrote:

>I'm assuming that the VCO on page 13 of this datasheet is linear;
>http://pubpages.unh.edu/~aperkins/pdf/LM-devices/LM339.pdf
>
>If it components were chosen for the audio range (close as possible), and a
>good exponential converter was added to the input, would this make an
>acceptable VCO?  Also, how difficult would it be to add hard/soft sync and
>PWM?
>
>These questions are kind of intended to be a general query about all of the
>overly simple VCO circuit that you find "out there".
>
>
>  
>