low-temp-drift ssm2164 VCO

[Roman Sowa]

Hi all,

Let me have the pleasure of presenting new (for me)
VCO with *no* tempcos and *no* heater, but still
not bad in terms of temperature stability.
This circuit was born in discussion with
Paul Maddox in private mail.
It is based on my beloved SSM2164 quad VCA chip,
and it's ten times more stable than my last VCO.
It isn't stable as a rock, but still enough for me
to make next module with it.

I did thermal tests using finger for heating, and
blowing air for cooling, so I guess temperature
change was about 10-15 deg. Over this range
the frequency drifted like this:

4Hz	0,2%
100Hz	0,5%
550Hz	0,1%
1.5k	couldn't notice
11k	0,3%

Any comments, and improvement tips appreciated

Roman

PS It's only 5K file. Hope you don't mind...

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