Doepfer

the reason i think is that the triangle wave is much easier to produce than the sine.

correct me if i'm wrong, Dieter.


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--- On Mon, 5/18/09, Greg Cerveny <greg.cerveny@gmail.com> wrote:

From: Greg Cerveny <greg.cerveny@gmail.com>
Subject: Re: [Doepfer_a100] A143-4 Quad vc-LFO/VCO
To: Doepfer_a100@yahoogroups.com
Date: Monday, May 18, 2009, 7:29 PM











    
            
            


      
      Forgive my naivety, but why no sine wave? Isn't that the most common lfo shape?



On Mon, May 18, 2009 at 10:15 AM, Malte Stamm-Gadow

<m.stamm-gadow@ innamorati. de> wrote:

>

>

> If the A-143-4 can be used as tonal VCOs, I will buy one.

>

> greetings, claas

>

> Am 18.05.2009 um 15:25 schrieb <david.salter@ thomsonreuters. com>

> <david.salter@ thomsonreuters. com

>>:

>

>>

>>

>> Agreed re: tempco's, the prospect of 4 basic VCO's that track over say

>> 3, 4 or 5 octaves would be very cool.

>>

>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

>> * *

>> * * *

>> David Salter

>> Senior Consultant

>> SSG UKI

>>

>> Thomson Reuters

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>> From: Doepfer_a100@ yahoogroups. com [mailto:Doepfer_a100@ yahoogroups. com

>> ]

>> On Behalf Of Andreas- theCovertOperators. Org

>> Sent: 18 May 2009 14:17

>> To: Doepfer_a100@ yahoogroups. com

>> Subject: Re: [Doepfer_a100] A143-4 Quad vc-LFO/VCO

>>

>> Guy Drieghe D. skrev:

>> > I'm with Richard. Tempco in LFO's seems a bit like overkill here...

>> that's right, it would be overkill... but these are tempco'd

>> OSCILLATORS, which means that you can use this as four VCO voices in a

>> patch! THAT is the really interesting bit about this unit, if you ask

>> me.

>>

>> andreas

>>

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> 


 

      

    
    
	
	 
	
	








	


	
	


      

[Non-text portions of this message have been removed]

> the reason i think is that the triangle wave is much easier to
> produce than the sine.
>
> correct me if i'm wrong, Dieter.

Whenever one designs an oscillator one has to decide which is the core
oscillator (e.g. sawtooth for A-110, triangle for A-111 and most of the
LFOs, sine for A-143-9). The other waveforms have to be derived by waveform
converters from the core waveform which always leads to imperfections
(except rectangle which is easy to generate by a comparator). The A-143-4
uses a triangle core. A voltage controlled oscillator with a perfect sine is
already available: A-143-9

If we expand the A-143-4 by everything that is available in other
oscillators (additional waveforms, range or octave switches, hard sync, soft
sync, linear FM, additional CV inputs, LED display ...) the front panel
width and the price will increase and the advantage of a compact module with
only the most important functions is lost. The problem is to find the right
compromise between functions and price.

Best wishes
Dieter Doepfer

I agree Dieter

cheapness is an important feature of this module

and I think LEDs and audio frequencies are very worthwhile features!

Richard


yahoo@doepfer.de wrote:

> 
> 
> 
>  > the reason i think is that the triangle wave is much easier to
>  > produce than the sine.
>  >
>  > correct me if i'm wrong, Dieter.
> 
> Whenever one designs an oscillator one has to decide which is the core
> oscillator (e.g. sawtooth for A-110, triangle for A-111 and most of the
> LFOs, sine for A-143-9). The other waveforms have to be derived by waveform
> converters from the core waveform which always leads to imperfections
> (except rectangle which is easy to generate by a comparator). The A-143-4
> uses a triangle core. A voltage controlled oscillator with a perfect sine is
> already available: A-143-9
> 
> If we expand the A-143-4 by everything that is available in other
> oscillators (additional waveforms, range or octave switches, hard sync, soft
> sync, linear FM, additional CV inputs, LED display ...) the front panel
> width and the price will increase and the advantage of a compact module with
> only the most important functions is lost. The problem is to find the right
> compromise between functions and price.
> 
> Best wishes
> Dieter Doepfer
> 
>

>The other waveforms have to be derived by waveform
> converters from the core waveform which always leads to imperfections
> (except rectangle which is easy to generate by a comparator). The A-143-4
> uses a triangle core. A voltage controlled oscillator with a perfect sine is
> already available: A-143-9

dieter, is it possible to convert the waveforms after they have left the module? i would have thought that would make an interesting and valuable module.
> 
> If we expand the A-143-4 by everything that is available in other
> oscillators (additional waveforms, range or octave switches, hard sync, soft
> sync, linear FM, additional CV inputs, LED display ...) the front panel
> width and the price will increase and the advantage of a compact module with
> only the most important functions is lost. The problem is to find the right
> compromise between functions and price.

i'm also in favour of less-is-more (and uses less space). but i guess the range switch would be essential for those using the module as tuned vco's, otherwise tuning it would be somewhat clumsy, as it is when using a self-oscillating filter. on the other hand, one huge sweep from top to bottom is a fine thing :)

octave switches can be realized externally,

led's: hmm, the pros and cons are obvious enough. but i think i'd come down on the side of space and cost saving, although i can imagine forgetting which lfo is going where :) but my main interest is having four vco's.

how bad does the tuning get without temperature compensation?

thanks,

stu

> If we expand the A-143-4 by everything that is available in other
> oscillators (additional waveforms, range or octave switches, hard sync, soft
> sync, linear FM, additional CV inputs, LED display ...) the front panel
> width and the price will increase and the advantage of a compact module with
> only the most important functions is lost. The problem is to find the right
> compromise between functions and price.
> 
> Best wishes
> Dieter Doepfer


hello dieter,

regarding the a143-4 i would vote for
additional leds, reset inputs and range switches.
these features would really add to the overall
functionality of the a143-4 as a lfo.

the reset inputs are often totally underestimated,
but from my point of view they are incredibly
useful, especially in a quad design.

best wishes

ingo