[sdiy] Another view to: Doepfer A-105 looks like Oakley Multiladder?

[Florian Anwander]

Hi Tony 

There are three facts, that should be mentioned in this topic.

The first: 
Beside the Oakley Multiladder and the A-105, I remember two other filters with
the identical feature:
- a prototype of a Technosaurus VCF shown some years ago 
  on the Frankfurt Music Fair. This one never went into production
- The filter of the jomox SunSyn (in production since a half of a year, 
  concept published two years ago)

The second:
Inspired by the Formant 24 dB VCF (which did some similar thing, with OTA filter
stages), I experimented with a Curtis 24dB Lowpassfilter (Doepfer A122) with
separate stages (I only used the second and the fourth stage), and did some (not
very successful) experiments with the Roland Filterchip of the JX3P. I think I
mentioned this once here in the list.
I talked with Dieter nearly two years ago about this idea. He argued that time
that he does not want to rely on Curtis Chips, and the OTA-solution he did not
like, and so the idea vanished in the bottom drawer.

The third:
A insert for the Feedbackloop exists as pin contact on nearly every Doepfer
Filter PCB (as far I remember also on the MS404). So the A-105 is nothing
unconventional for Doepfer; it is only the first Filter, where he fed this
connections to the frontpanel.


I forwarded your mail to the editors of the german magazine Keys, with URLs of
the multiladder, JHs Wasp filter clone. They were also active in the copyright
conflict between Mackie and Behringer.

Florian

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Florian Anwander                  |ConSol*  HP-Support
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