[sdiy] using LM13700 in differential mode to reduce trimmers

[Eric Schlappi]

You guys are right.

I had an instance a while ago where the lm13700 in a differential mode
sounded much better than it did when I used it single endedly so I was
thinking maybe it got rid of the offset but I went back and re-read guest's
paper for the thousandth time and it definitely wouldnt. Would still need a
trimmer.

It does look like it helps with the signal to noise ratio though so it's
probably worth doing anyway.

I guess I was wondering why I don't see the lm13700 used with differential
input more often, or am I still missing something?

On Mon, Oct 26, 2020 at 1:03 AM Roman Sowa <modular at go2.pl> wrote:

> How can differential input do anything with internal LM13700 offset?
> It's still there. Nothing changed.
>
> Roman
>
> W dniu 2020-10-25 o 22:00, Eric Schlappi pisze:
> > Hi All,
> >
> > I've been experimenting with adding an inverting op amp and driving my
> > LM13700 (and other OTA circuits) differentially, which seems to let me
> > drop the traditional offset trimmer. I am also using precision thin
> > film resistors, which might help too.
> >
> > Anyone else been down this path with positive or negative results?
> >
> >
> >
> > Thanks,
> > Eric
> >
> > _______________________________________________
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> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
>
>
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