Doepfer

sorry, you are right.
my fault!



laryn91 schrieb:
>
> That's in the A-110 info page - NOT the A-111. Right?
>
> --- In Doepfer_a100@yahoogroups.com 
> <mailto:Doepfer_a100%40yahoogroups.com>, Pieter Volger <volger@...> wrote:
> >
> > RTFM
> >
> > "_Technical remarks:
> > _The core of the A-110 is a sawtooth oscillator (in contrast to the
> > A-111-1 <http://www.doepfer.de/a111.htm 
> <http://www.doepfer.de/a111.htm>>, which is based on a triangle
> > oscillator). The other waveforms are derived from the sawtooth by
> > internal waveform converters. As the sawtooth reset (i.e. the
> > back-to-zero slope) is not infinite fast but takes a little bit of time
> > the derived waveforms triangle and sine are not perfect ! At the top of
> > the waveform they have a small glitch or notch that is caused by the
> > sawtooth reset and cannot be eliminated by the waveform converters. The
> > sine is derived from the triangle by a simple diode-based converter and
> > the sine shape is not perfect (only a rounded triangle).
> > If a perfect triangle is required the A-111-1
> > <http://www.doepfer.de/a111.htm <http://www.doepfer.de/a111.htm>> is 
> recommended. For a perfect sine the
> > quadrature LFO/VCO A-143-9 <http://www.doepfer.de/a1439.htm 
> <http://www.doepfer.de/a1439.htm>> is recommended.
> > "
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > laryn91 schrieb:
> > >
> > > > And we will point out in the module information and user's guide of
> > > A-110
> > > > and A-111 that the sine outputs should be called more precisely
> > > "sine-like".
> > >
> > > Dieter,
> > >
> > > It's probably just me, but where do you point that out for the A-111?
> > > In my A-111 manual
> > > you say just the opposite:
> > >
> > > "Sine waves are pure waves: they just contain the
> > > fundamental, without any harmonics (see Fig. 5).
> > > They are thus not suitable for subtractive synthesis
> > > (shaping sound with a filter) - as there's nothing to take
> > > away!"
> > >
> > > To the contrary, the A-111 sine is still suitable for subtractive
> > > synthesis. To be accurate,
> > > you should say "not suitable for additive synthesis" instead.
> > >
> > > >If you want a perfect sine you need a VCO
> > > > with a sine core.
> > >
> > > Instead of an impossible "perfect sine", how about just a sine 
> with no
> > > *audible* overtones
> > > (<1% THD) like Arp, Moog, Aries, Polyfusion, EML,etc. used to make?
> > > That would now
> > > make the A-111 useful for additive synthesis and FM.
> > >
> > > All you need to do is copy their simple but superior triangle-to-sine
> > > converter design. ;-)
> > >
> > > --- In Doepfer_a100@yahoogroups.com 
> <mailto:Doepfer_a100%40yahoogroups.com>
> > > <mailto:Doepfer_a100%40yahoogroups.com>, <yahoo@> wrote:
> > > >
> > > > I will not participate in the emotional discussion about sine waves
> > > but want
> > > > to mention some technical details (some of these have been already
> > > mentioned
> > > > earlier):
> > > >
> > > > All standard VCO circuits I know are based on a sawtooth or 
> triangle
> > > core.
> > > > When the sine wave is derived from one of these VCO cores you 
> will never
> > > > obtain a perfect sine. The antiparallel diodes are the simplest
> > > solution to
> > > > derive a sine-like wave from a triangle, the FET circuit is a bit
> > > better but
> > > > even far away from beeing perfect. Each kind of waveform 
> converter is a
> > > > compromise (except rectangle). If you want a perfect sine you 
> need a VCO
> > > > with a sine core. And in return: if you want a perfect triangle you
> > > need a
> > > > VCO with a triangle core, if you want a perfect sawtooth ...
> > > >
> > > > The A-143-9 is the only oscillator in the A-100 that uses a sine 
> core.
> > > > Though it was not planned as a VCO but mainly VCLFO it can be
> > > (ab)used as
> > > > sine VCO. The main drawback of the A-143-9 is the missing 
> temperature
> > > > compensation of the exponential generator. We consider to develop a
> > > sine VCO
> > > > based on the A-143-9 circuit but with a temperature compensated
> > > exponential
> > > > generator. I expect that the price would be in the Euro 100 range.
> > > We are
> > > > also working on a VCO with sine core and linear FM with thru-zero
> > > feature.
> > > > But this is another "construction site" because the linear FM and
> > > thru-zero
> > > > feature is much more complicated than adding "only" the temperature
> > > > compensation.
> > > >
> > > > And we will point out in the module information and user's guide of
> > > A-110
> > > > and A-111 that the sine outputs should be called more precisely
> > > "sine-like".
> > > > But even rectangles or triangles are not perfect (each rectangle is
> > > kind of
> > > > trapezoid as each rising and falling edge has a slope that depends
> > > on the
> > > > inherent slew limiting characteristic of analog circuitry).
> > > >
> > > > Best wishes
> > > > Dieter Doepfer
> > > >
> > >
> > >
> >
>
>