CEM3330 VCA oscillating

Tony Allgood oakley at techrepairs.freeserve.co.uk
Tue Mar 7 20:46:06 CET 2000

Hi Ingo and all,

I may be wrong here, but I remember reading that the Curtis VCA suffered
from overheating and would oscillate. I don't know whether this would be
a gradual thing over time, or that the bad ones did it from the word go,
but the solution was to run the thing off a 12V supply, not 15V. It was
the E&MM Spectrum article that had this, but it was a long time ago when
I read it.

The Poly Formant did the same to the CEM3340 VCO as well. At +10.5V
& -5V it ran cooler and the drift was better.

But if you go for a piggy back VCA, use the BA6110. Much better than the
LM13700, and smaller, and cheaper.


Tony Allgood  Penrith, Cumbria, UK

BTW: Have I said that I have some little PCBs for sale that do just the
job... of course, I have, I just had to say it again.

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