Polysix VCF -- Re: [sdiy] Hello, everyone! (and some filter mumblings)

[john mahoney]

----- Original Message ----- 
From: "cheater" <cheater at salsa.pl>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, June 23, 2004 10:45 AM
Subject: [sdiy] Hello, everyone! (and some filter mumblings)


> Hay guys,
>
> first off, I'm a newbie to electronics more advanced than
capacitors/resistors in combinations.

Welcome to the club! :-)


> Anyhow: I want to start my synth adventure making an analog filter ...
> ... Korg Polysix sound - I can't find any schematics ...

The Polysix (like the Mono/Poly) uses the SSM 2044 VCF chip.

Polysix schematics are available for purchase, so you can obtain the VCF
circuit. Or, simply make your own filter based on the sample circuit in the
SSM datasheet (or Barry Klein's slight variation of it -- I think that's in
Electronotes).

Just download the SSM 2044 datasheet from
http://www.synthdiy.com and look at Figure 3. Simple enough? :-)


> Sure, I can find a lot of schematics for the Moog filter, but that's not
exactly what I'm
> looking for... basing on my experiences with Moog synths. I'm looking for
something warm, neat,...

Actually, that *is* what you are looking for. The 2044 emulates the Moog
4-pole filter, and supposedly came closer than any other IC, so they are
more similar than different. Perhaps someone can elaborate on the fine
points of the 2044 compared to a Moog filter.

The MOTM 490 VCF may sound good to you, as it's a "1970s-style" 4-pole
filter. Building a kit can be a good way to get your feet wet. Then again, a
2044-based circuit is rather simple.
--
john