Steiner VCF Self Oscillation

[Sebo]

Hi Yves:
My Steiner VCF doesn't oscillate, I thought that the circuit works that way, but
recently I see a video of a a guy that built the filter and was self oscillating
in the video.
The design is meant to self oscillate?
If I lower R16 could I make it self oscillate?
Thank you.

Sebo

[yusynth]

The Steiner screams or yells rather wistling when it auto-oscillate. Furthermore when lock in auto-oscillation it has difficulties to track.

If your filter does not auto-oscillate you have to play with the value of R16 (if this is the CA3096 version). You would have to increase it (560 or 680 ohm).

Beware it is very hard on the tweeters !

[Sebo]

Hi Yves:
I was looking at the wrong schematic, I built the 2SC1583 version, and
used a 25K pot for resonance and 27K for R13.
To be sure I checked R13 with my multimeter, then the pot, and I get
surprised because the pot reads 20.8K!!!
I always forgot that pots have a tolerance of 20%, so 25K could be as low
as 20K.
Then I should get R13 back to 22K (or less), right?

[Sebo]

I changed R13 to 22K and now the filter is self oscillating when the resonace
pot past the 8 mark.
Great!!!
Thanks Yves!!!

[Sebo]

Well... I run some sequences using the new value of R13 and finally I
added a 2K resistor in series with R13 (22K) because the oscillation was
too much (it could kill my ears at any moment). Now it oscillates when
I pass 8.5 and only get that speaker blowing oscillation if I go over 9.5.