[sdiy] 3320 as SVF

[harry]

I built the data sheet version... no bleedthrough problems for me.

H^)

Tony Allgood wrote:

> Hi all,
>
> This is a topical thread for me right now too. I have a OB-Sx module
> racked up and in use as a little mono. Very nice, I like its sound but
> for one thing. The filter suffers from very bad CV bleedthrough. Now it
> features a 3320 as two pole filter, similar to that in the OB-8, but
> without the four pole or the switching found in later Oberheims. Has
> anyone else noticed undesirable bleedthrough when Q is low?
>
> The datasheet for the 3320 has a little trimmer added to one of the
> supply rails to control CV rejection. I added this, but it made little
> effect. Any ideas? Bad 3320, or just bad design in the first place?
>
> Regards,
>
> Tony Allgood  Penrith, Cumbria, England
>
> Oakley Modular Synth and TB3030:
> www.techrepairs.freeserve.co.uk/projects.htm
> My music: www.mp3.com/taklamakan