[sdiy] Weird MFOS VCO max CV problem

[Travis Thatcher]

Yeah, it uses an LM13700 OTA.

On Mon, Apr 9, 2012 at 4:53 PM, Ove Ridé <nitro2k01 at gmail.com> wrote:
>
> I've had a similar problem with a VCF. I don't know what the cause is
> at this point, but I suspect it may have to do with over-spec control
> current to a ca3080, which is an OTA. Does MFOS VCO utilize any OTAs,
> such as the ca3080, ca3280 or LM/NJM13x00?
>
> On 9 April 2012 19:26, Travis Thatcher <recompas at yahoo.com> wrote:
> >
> >
> > I've had a MFOS VCO in my rig for some time now and its more or less
> > been functioning well.  I finished it as a build a friend started and
> > had some initial problems but after going through the circuit everything seemed to be okay. The problem I'm having is that if you feed it a CV
> > above a certain threshold, when the pitch is high, the VCO just turns
> > off. I suspect the summing op amp for CV is just getting stuck in a
> > state where its hitting the rails, but I've tried a few different chips
> > to be sure that's not the issue.  Not really sure where else to poke
> > around to troubleshoot this. Has anyone else ever had this problem?
> >
> > Travis Thatcher
> > ___________________________________
> >
> >
> > http://www.recompas.com
> > http://voiceofsaturn.blogspot.com
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>
>
> --
> /Ove
>
> Blog: <http://blog.gg8.se/>
>
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