FW: completely *reasonable* question...

[Harry Bissell]

You can have a VCO that accepts both positive and negative voltages... It really
depends on the design of the VCO. Some VCO's (called through-zero) actually stop
at zero volts and then go "backwards" (increasing again in frequency, but
opposite in phase... so a ramp that rises slowly, then falls fast would become a
ramp that rises fast, then falls slowly.  The 1V/oct standard is just for music
uses... other linear VCOs have other ranges... WAY beyond human hearing if you
like...

What kind of filter are you thinking of.... The idea of "constant output" might
depend on whether you mean constant in (like) Voltage, or Power, or Human
Perception of Output
(like Volume ???).

What did you want to do with this thing ???  We can help !! (we like to play
too...)
Or if it is secret then give us a hint ???

H^)


> > Hi everyone,
> ...
> > I want to build a selfoscillating "tonebox", a VCO and a VCF, which has a
> > constant output.
> Not sure what you mean by constant output... You mean no VCA?
>
> > What should the cv input to the VCO be, more specific:
> > what is the standard cv range for pitch. Is it +5V to -5V?
>
> The VCO CV is most often formatted as a 1V/Octave signal. Each 1V increase
> results in a 1 octave increase in pitch. Internally, a VCO usually needs a
> CV that ranges from 0V to "whatever your max octabe is" (typically 10V).
>
> In normal applications, your box would have a VCO CV input jack and a
> coarse/fine tune knobs or switches. The actual CV going into the VCO would
> be a sum of these controls/signals.
>
> Therefore, it is quite reasonable to put negative voltages into your VCO CV
> input (If you were feeding audio waveforms into the VCO CV jack for example)
> as long as the total sum (going to the VCO) is not negative.
>
> I hope that helps clear things up a bit,
> -Dan G.