Doepfer

Ahh... the Schumann custom stuff.  I hear it's very nice stuff.

Regards,
Kevin

--- In Doepfer_a100@yahoogroups.com, "ps_minor" <pscottm@h...> wrote:
> hey that sounds nearly identical to my new favorite device, a box a 
friend of 
> mine has put into production recently, called simply the PLL.   
it's an amazing 
> thing..  mine will have CV added soon, and an arpegiator for 
cycling through 
> harmonics.  it has germainium overdrive circuits built into the 
mixer controls 
> and a waveshaper on final output.  very musical device!
>   
> have a look:
> 
> http://members.toast.net/photos/album.asp?user=pscottm&album=
> schumann%20PLL
> 
> also, i just loaned him a doepfer mini power supply/bus board & 
blank panel 
> so he can develop one in euro module format.  (actually, it'll just 
be the PLL 
> 'front end' osc control circuit, not the multiplier/divider, or 
mixer.
> -psm
> 
> 
> 
>  Lindholm" <andreas.k.lindholm@t...> wrote:
> > That sounds interesting to me although I don't completey grasap 
it, but the
> > wobbling and inaccuracy in this case could be more advatageous as 
an 
> effect
> > than a pure VCO it seems to me... when did this module come up on 
the
> > agenda? I didn't even know it was something Doepfer had in 
mind....
> > 
> > 
> > ----- Original Message ----- 
> > From: "Bakis Sirros" <synth_freak_2000@y...>
> > To: "Doepfer_a100 group" <doepfer_a100@yahoogroups.com>
> > Sent: Thursday, June 26, 2003 6:06 PM
> > Subject: [Doepfer_a100] a brief explanation about the uses of a 
PLL
> > VCO.(from doepfer.)
> > 
> > 
> > > dieter says:
> > > "a PLL and it's application is not very easy to
> > > understand. I will try to write an explanation and
> > > publish it on our web site as soon as we publish the
> > > preliminary page for the PLL module (no A-100 number
> > > so far).
> > > Here is a simplified explanation: A PLL is a linear
> > > rectangle VCO with a frequency comparator that
> > > compares the frequency of the internal PLL-VCO with an
> > > external frequency (master frequency) - e.g. the
> > > rectangle output of  "normal" A-100 VCO - and makes
> > > the the internal VCO frequency equal to the external
> > > frequency. Or better said: it tries to adjust the
> > > internal frequency so that it becomes equal to the
> > > external frequency. The problem is the frequency
> > > comparator - even called phase comparator - that
> > > generates a kind of a correction voltage that becomes
> > > zero if both frequencies are identical. Different
> > > versions with different advantages/disadvantages of
> > > frequency comparators are available. Some types of
> > > comparators e.g. will "lock" even at multiples of the
> > > frequencies. Another problem is the time that is
> > > necessary until the PLL-VCO is adjusted. It will
> > > always take some time until the new frequency of the
> > > PLL-VCO is reached (similar to portamento). The time
> > > constant of the internal low pass filter (not an audio
> > > low pass but a low pass/slew limiter for the
> > > correction CV) defines the time until the new
> > > frequency is reached. But this time has not to be too
> > > short otherwise the frequency of the PLL-VCO will
> > > "wobble" around the master frequency. These
> > > "disadvantages" lead to additional musical
> > > applications like portamento effects or wobbling
> > > frequencies according to the type of frequency
> > > comparator and time constant of the PLL low pass
> > > filter.
> > > Another application is frequency multiplication in
> > > combination with an external frequency divider. For
> > > this the output of the PLL-VCO is processed through a
> > > frequency divider (e.g. A-160, A-161, A-163) before it
> > > is fed to the PLL frequency comparator. In this case
> > > the frequency of the PLL-VCO will be a multiple of the
> > > master frequency. E.g if the the A-163 is used and
> > > adjusted to dividing factor 5 the frequency of the
> > > PLL-VCO will be 5 times the frequency of the master
> > > VCO. Consequently frequency division (A-163) leads to
> > > frequency multiplication with the PLL circuit. In
> > > combination with the PLL low pass frequency several
> > > effects can be realized (frequency multiplication with
> > > portamento or wobbling). The frequency multiplication
> > > can even be used to drive a graphic VCO. If your
> > > graphic VCO e.g. has 8 steps (e.g. A-155) and you use
> > > a frequency divider with factor 8 in the PLL feedback
> > > the output of the graphic VCO has the same frequency
> > > as the master VCO. Another application is the
> > > generation of pseudo-harmonics (not real harmonics as
> > > only rectangle waves are available).
> > >
> > > I hope this explanation will help and not cause more
> > > confusion. I know that the PLL is not very easy to
> > > understand.
> > > Best wishes
> > > Dieter Doepfer"
> > >
> > >
> > >
> > > INTERESTING???????OF COURSE,YES!
> > > bakis.
> > >
> > >
> > >
> > >
> > > =====
> > > synthfreak(parallel worlds)
> > > athens-greece
> > > [Doepfer_a100] group owner
> > >
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