[sdiy] Sine-wave VCOs?

[Thomas Dunker]

On Mon, 3 May 2004, john mahoney wrote:

> Yes, for a subtractive synth, there's little reason to make a VCO that
> produces only sine waves. The goal is to have many different waveforms
> available.
>
> A cool application of sines is in the CS-80, where you can mix an unfiltered
> sine with the output of the VCF. This adds the pure fundamental, e.g. for
> adding bass power without adding upper harmonics.

 I've been doing some thinking along these lines, trying to get as much as
possible out of the single VCO I will have on my portable modular (not
enough space for two VCOs anyway...).
I've decided I want to include a "waveform mixer" on the VCO, where sine, tri,
saw, sqr and two sub frequencies can be mixed and "panned" into two
separate composite waveforms, which can then be modulated and filtered
independently. In addition to this I will squeeze in some triode distortion
so that the sine wave can be anything continually variable from pure sine via
asymmetrical to symmetrical tube saturation.
 These features, I reckon, will give me an infinite set of possible
waveforms and a great deal of control over the harmonics coming out of the
VCO beyond the simple "standard" waveforms.

 I imagine that 'composite' waveforms synthesized this way would also be
interesting coming out of an LFO to create weird, irregular modulations.

 Anyone into ideas like these, or do you all have enough modules to post
process/mix VCO waveforms elsewhere in your systems??

Thomas Dunker