[sdiy] VCO that goes SHARP in highest octaves??

Ben Bradley ben.pi.bradley at gmail.com
Thu Jun 9 05:40:35 CEST 2022


Rereading the original, it seems reasonable to assume at least one
component is different in SMT from thru hole. I'd start replacing SMT
parts with thru hole and see what happens. I can't quite say why, but
I'd start with Q5 and Q6, and if no change then Q1-Q2. From there I'd
do the other active parts. After what you've already tried, this does
not have an easily identifiable solution.

On Wed, 8 Jun 2022 at 21:15, Neil Harper via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
>
>
> On 5/19/22 15:57, Sarah Thompson via Synth-diy wrote:
> > Chip ceramic capacitors can show changes in capacitance with bias
> > voltage. If stable capacitance is necessary, then specifying something
> > fundamentally more stable like a polyester might be sensible, albeit at
> > the cost of board area.
>
> thank you sarah,
> this is good to know, so I did try swapping the smt cap out with the
> npo/c0g thru-hole cap that worked as expected and the problem did not
> change.
>
>
> --
> /// Neil Harper
> /// Every Wave is New Until it Breaks
>
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