switching at zero cross/noiseless switching

Buck Buchanan voltagecontrolled at home.com
Thu Nov 11 07:39:46 CET 1999


Hi Don, thanks for the input!


>    And furthermore, if I did manage to make it switch at the zero
>    crossing, wouldn't this be eliminated?
> 
> No it wouldn't.  You're thinking of delaying the switching until input
> A crosses zero, right?  But then it's unlikely that input B is
> crossing zero at that very moment and so switching to input B will
> cause a click.  It would be no less noisey.

I think I should have explained the module better.  It takes one input
and fans it out to one of 4 outputs.  So there's only signal A - there's
nothing at B (C or D) until A is switched there.

> >> Proposal 2:
> You could do a 2-step switch, like this:
>  Wait for input A to cross zero.
>  Switch from input A to mute.
>  Wait for input B to cross zero.
>  Switch from mute to input B.

Now that would be an interesting circuit to get running!
 
> This might work well, I'd be interested in hearing it in a real synth
> situation.

It should be fun.  This whole quest started as a way to do cheap/simple
4 channel circular location modulation without all the VCAs, quadrature
oscillators, etc.

Thanks for the suggestions!

Buck



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