[sdiy] Working with ASM1 VCO.. TEMPCO resistor Temperature compensation

[Spiros Makris]

Hello,
This paper details some methods of thermal compensation and shows the
derivation of the formulas for the expo converter and the thermal
compensation resistor choice.
http://www.openmusiclabs.com/files/expotemp.pdf

Spiros

On Mon, Jan 20, 2020 at 6:50 PM Jean-Pierre Desrochers <jpdesroc at oricom.ca>
wrote:

> Hi René,
>
> >> Or just a voltage divider to get a final 18mV/oct to Q1 ?
> >Yes. As long as the top resistor is much larger than the bottom, you
> should be fine.
>
> Ok I understand. As stated I was thinking of a 33k for R9 instead of 56k.
> This would be 33 times higher than 1k.
> Still far enough ?
>
>
> **************************************************************
> -----Message d'origine-----
> De : Synth-diy [mailto:synth-diy-bounces at synth-diy.org] De la part de
> René Schmitz
> Envoyé : 20 janvier 2020 11:10
> À : synth-diy at synth-diy.org
> Objet : Re: [sdiy] Working with ASM1 VCO.. TEMPCO resistor Temperature
> compensation
>
> Hi Jean-Pierre,
>
> On 20.01.2020 16:54, Jean-Pierre Desrochers wrote:
> > If I change the R9 value  from 56k to 33k for new design reasons
> > will it affect the temperature compensation between the R14 TEMPCO and
> > Q1 ??
> >
> > Is this R9/R14 ratio important temperature wise
>
> No its not important. You will have to change the gain of the opamp, to
> get 1V/oct.
>
> > Or just a voltage divider to get a final 18mV/oct to Q1 ?
>
> Yes. As long as the top resistor is much larger than the bottom, you
> should be fine.
>
> Best,
>   René
>
> --
> synth at schmitzbits.de
> http://schmitzbits.de
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