patchell patchell at
Sun Nov 7 17:40:09 CET 1999

Christian Baumann wrote:

> Hello to all,
> thank you very much for your information!! :-)
> I looked around in the websides you recommended and it´s quite a flood
> of information for me and I don´t know where to start.
> I try to "repeat" about the necessary itmes of an analog synth, so far
> as I understood ( please correct me if I am wrong.....and I thing there
> is something wrong ).
> First I need the VCO´s for creating the waveform´s , like sine, triangle
> and propably rectangle and pulse.

    Actually first priority is saw and pulse, these are probably the two
most interesting (rectangle and pulse would be the same thing).  Sine and
triangle have their uses, but are a lot less harmonically rich.

> Then  VCF´s to filter them and finally a VCA to amplify them.
> Somewhere there must be the LFO´s for a kind of  bass for example, but I
> don´t know where to put them in. Then there are the ADSR-Controlsliders.

    LFO's are used as modulation sources, generally.  You use them to get
vibrato (Frequency Modulation), Tremolo (amplitude modulation), and also for
pulse width modulation of you pulse wave.

> Finally a good power supply, it must be very good, I think, because if
> the voltage drops around some milivolts, the note will be out of tune,
> or ??
> Then, I´ve got still some questions:
> Are the sine, triangle rectangle basic waveformes, where it is poosible
> to mix all thinkable sounds like a strings or piano ??
> I compared it to the primary colours red, yellow and blue, where you can
> mix all thinkable colours.

    Actually, generally, with analog synths, it is more like starting with
white and removing the colors you don't want until you end up with what you

> Thus you may need three VCO´s, for creating the waveforms, VCF to soften
> a particular waveform and then the VCA to get a stronger signal. Could
> be that a structure of an anlog synthesizer ??

    VCA is more to control the dynamics of the sound.  Each type of
instrument has a characteristic build up (Attack) and dies down (Decay) in
it's own way.  The Envelope generator (ADSR or AR) is used to control this.
The envelope generator can also be used to control the timber by modulating
the VCF.

> What happened if I would take more VCO´s ??

    The more the merrier.  The number of VCO's is generally dictated by
cost.  The VCO is probably the most expensive module to build because it
needs to be the most stable.

> The most personally synth´s which I have found in the internet are a
> kind of "box" and controlled by a midi-keyboard. Is it possible to build
> a synthi or has somebody in the list built a synthi which has it´s own
> keyboard ??

    It is posible to build a system from the keyboard up, but there are
several problems you will encounter these days.  Getting a keyboard is not
as easy as it was 20 years ago.  I purchased several for my projects back
then.  Several things have changed.  Midi is the most important.  It is
probably easier just to purchase a good keyboard that spits out Midi and
then purchase or build a Midi->Control Voltage converter (Paia has one,
among others).

> I looked at for the Fatman, and it sounds good. But if I
> would build this synthi, is it possible to upgrade it, like adding some
> more VCO´s ?

    I probably wouldn't upgrade the Fatman, but the Fatman would make a good
learning experience to get you familiar with analog synths in general.  From
there you can launch new projects.  I don't know about other people on the
list, but I don't do this for fun.  I am an addict.  I was on the wagon for
about 8 years until I found this list, and those old desires came

> I read about the different types of synthesizer and I liked very much
> the modular synthesizer, because of the inifnte possibillities of
> creating sounds. Is this also possible with an analog one ?
> Has somebody build such a modular type ?

    Actually almost all (not all, almost all) modulars are analog.  Building
a digital modular is not very easy.  If you want to part with about $1800,
take a look at this web site.

    This is probably one of the best digital modulars you can get, but it is
not a D.I.Y.  It is a virtual analog.  Building a virtual analog synth is
probably a bit more difficult to do, mostly because the IC's come in surface
mount packages with a gazillion very tiny pins that break by just looking at
them wrong.

> Sorry that I ask you so much, but I´m very curiouse about this.
> Christian


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