(FWD) Help with turning "+ CV" into "-CV"

[Theo]

He already got the answer :)
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----- Original Message ----- 
From: <media at mail1.nai.net>
To: Synth-DIY <synth-diy at node12b53.a2000.nl>
Sent: Wednesday, December 20, 2000 5:53 PM
Subject: (FWD) Help with turning "+ CV" into "-CV"


> 
> Someone posted this to another list.  If anyone here has an answer, I'll
> forward it back to him.
> 
> From: Plutonique9 <Plutonique9 at symbiocom.com>
> To: <Analogue at hyperreal.org>
> Date: Tue, 19 Dec 2000 06:21:36 GMT
> 
> I'm working on CV inputs for VCF and VCA on my CS01. I've added the
> inputs for the CV yet there is a slight "CV format" incompatibility.
> The VCF and the VCA respond to CV from 0 volts to -5 volts.
> So basically I need to rig up a circuit that will turn a regular
> positive voltage CV source (such as an LFO) into a negative voltage
> CV. I've been checking out schematics for Op Amp inverters, but I'm
> not sure if that is what i am supposed to build. Can anyone confirm
> whether this schematic will suit my application, this is supposed to
> invert the phase 180 degrees, but I'm not sure whether it will invert
> the polarity??????
> 
> http://www.eatel.net/~amptech/elecdisc/opamp4.gif
> 
> Maybe this is more a synth DIY question, but I'm not subscribed there
> yet
> -- Plutonique9, Plutonique9 at symbiocom.com on 12/19/2000
> 
> 
>