Copyrights of synthesizer circuits

Michael Zacherl - Bacher Systems EDV GmbH mz at
Mon Jun 19 03:22:38 CEST 1995

> I have a project to manufacture a semi-modular synthesizer and sell 
> it worldwide. The problem is that some of my modules are based on designs
> of other manufacturers. For example the filter is Moog ladder filter and 
> the oscillator is based on Moog Prodigy.

Sorry for being ignorant .. what's a 'semi-modular' synth.?

Hmmm ... currently there are a couple of synths out there having something similar to a moog ladder-filter inside. As far as I know patents of the Moogfilter are expired so there should be no problem (don't rely on that!).
Yamaha's FM-patent (or is it John Chownings??) will expire soon/is expired also.

On the other hand: How much in detailed something can be under copyright? E.g. a condenser decharging sawtooth-generator is something more or less common. The waveshape convertor afterwards is more or less standardtechnique (IMHO!). So I find it pretty hard to find a rule how to judge. Maybe if there is something unique or one solved a problem using new techniques? Can that be a parameter?

I've to admit that I've _NO_ experience in this everything's just 'out of the stomach'.



Michael Zacherl                   
phone :  +43 (1) 60 126-253         Bacher Systems EDV GmbH
fax   :  +43 (1) 60 126-4                Wienerbergstr. 11B
e-mail:  mz at                        A-1101 Wien
www   :        Austria-Europe

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