[sdiy] Any LM331 experts around?

[Mike I]

Maybe contact Bob Pease at Nat Semi - he designed it.

VCO in Roland Jupiter-4 ( JP-4 ) also a charge-balancing design with uA726
in front with digital range and waveform selection.
Mike


----- Original Message -----
From: Ian Fritz <ijfritz at comcast.net>
To: Paul Perry <pfperry at melbpc.org.au>; <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 14, 2008 8:49 AM
Subject: RE: [sdiy] Any LM331 experts around?


> At 10:08 PM 4/13/2008, Paul Perry wrote:
> >My guess - and it is only a guess - is that it puts a little
non-linearity
> >in the F/V curve, to compensate for a little gap when switching occurs.
> >Like the high end freq tweak seen in many synth VCOs.
>
> The reason I'm puzzled is that pin 2 is a dc bias point, so I'm not seeing
> a frequency dependence there.
>
> I made a homebrew charge balance VCO and compensated a bit of HF droop
with
> a small resistor in series with the integrating cap.  This kind of VCO is
> amazing.  Too bad the quasi-saw output isn't nicer.
>
>    Ian
>
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