[sdiy] VCA mixer ?

[TheeStateMachine at aol.com]

In a message dated 9/29/03 6:16:28 PM Pacific Daylight Time, 
pfperry at melbpc.org.au writes:


> >good luck, either way.  i looked into a project like this a while ago, and 
> 
> >gave up!
> Probably a sensible move!
> but, what do you think of my idea of using vactrols, with pics driving the
> leds with an ultrasonic PWM signal for control?

not an entirely unfounded idea.  quite nice, even.  

i must have missed your vactrol post... but since i had a bag of them laying 
around, i thought of the original poster's plight when mentioning the 
ssm2018's, 2164's and AD crosspoints,  and then thought of vactrols myself.  but 
"people other than myself would worry about the gain matching between chan's, 
surely", i thought.  (ordinarilly, i'd call people "weenies" for just such 
statements;)  as if their mackie mixers had better chan. matching!)

Your pic w/ pwm might might even quell that concern.  still,  how accurate 
can they be?  i suppose if each chan. has a trim pot, then matching should be no 
real problem.  not that i would need such precise editing on every single 
mix... but you know... for "mastering".   also, what advantage would the pwm 
oscillator have over a demux'd cv output?  is it just settling time (for the 
cv/demux) vs. aliasing (pwm)?  if it is, i wonder which might be easier to build, 
or for that matter, sound better.

i'd love to hear any more "input" you might have on the subject.

-paul
(that is, a "paul" other than paul perry)
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