...no subject...

[David Halliday (Volt Computer)]

Very very interesting!!!  I like it!

I can see that it would deliver a different "character" than your
traditional Noise/VCF combo.

You could also do a rate multiplier ( PLL with divider circuit ) to
multiply the VCO's frequency before routing it to the noise source...
The PLL is loose and springy and this frequency will not track the VCO
fundamental tightly but this could have it's uses too...


> -----Original Message-----
> From:	scgravenhor at amerhonda.com [SMTP:scgravenhor at amerhonda.com]
> Sent:	Tuesday, September 16, 1997 9:01 AM
> To:	synth-diy at horus.sara.nl
> Subject:	...no subject...
> 
> On Tue, 16 Sep 1997 08:43:55 -0700, you wrote:
> 
> >The circuit in question ( ETI 4600 page 20 ) couple be expanded
> without
> >too much problem.  The only question is that you would then be having
> to
> >deal with as many as ten ICs with their power and real-estate
> >requirements as well as the resistors and capacitors needed for the
> >clock generator.  A traditional noise source just requires a few
> >resistors, capacitors, a noisy transistor and one op-amp.
> >
> >You don't double the circuit or cross-couple it, ( there is only one
> >input and it is just a fixed frequency clock signal ) you would have
> to
> >extend the length of the PSR-SG and add more taps to the feedback
> >circuit.  Easy enough to do and, if it was made long enough, it
> wouldn't
> >suffer from periodicity problems.
> >
> >Still, the traditional noise sources are quick, easy, simple and
> >small...
> >
> 
> My approach was to use a 32 bit design (for virtually NO repeats) and
> I drive it from a VCO.  The effect of this is similar somewhat to
> filtering,
>  
> but it does sound different.  I used a standard VCO circuit and added
> a CMOS buffer to it's square wave output.  The VCO can then either be
> set at some particular frequency (as in the fixed oscillator above) or
> 
> can run around following a pitch CV or any other CV.  You can play
> noise
> melodies and other special effects.  This adds a dynamic unobtainable
> from the back biased transistor method.  Besides, the VCO can be used
> as, well, a VCO!  I needed an extra one anyway...
> 
> 
> -- chordman at flash.net <Synthaholic>