variable resistances (Re: [sdiy] Multi-Input filters)

[Tim Parkhurst]

I think this is how the PAIA 2700 / 4700 VCAs and VCFs worked. Simple,
fairly efficient, and cheap! Of course, they didn't have expo response and
drifted like crazy, but they sure got a lot of people started in
synthesizers.

Tim Servo
"Imagination is more important than knowledge." - Albert Einstein
********************************************************** 

> -----Original Message-----
> From: Roman [mailto:modular at go2.pl]
> Sent: Wednesday, February 12, 2003 7:12 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: variable resistances (Re: [sdiy] Multi-Input filters)
> 
> there's even a parameter specified for zeners, called dynamic
> resistance, that says what resistor would be connected to ideal
> brickwall zener to have response like real zener. And it changes with
> current. Personally I'd pick small zeners from 2V7 - 3V6 range. They
> have smoother knee, and should be easier to use.
> Add some caps, drive it with variable current and you have zener
> filter!
> 
> Roman
> 
> 
> benno <benj at iinet.net.au>:
> 
> >on that note, i had the thought that the reverse breakdown of a
> zener diode
> >would behave more like a current controlled resistor than a normal
> diode
> >would.
> >
> >or am i more full of shit than harry?
> >
> >B
> >
> >on 11/2/03 12:32 PM, harrybissell at harrybissell at prodigy.net wrote:
> >
> >> This IS the case for all the diode type transconductors where we
> vary
> >> standing current
> >> and voltage changes only slightly. I presume my explanation
> expands on this
> >> idea... or I'm
> >> full of sh!t. whaddya think ???
> >>
> >> H^) harry
> >
> >



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