Doepfer

On the A-137 page there are some green/black figures demonstrating 
control setting effects. They seem to be real oscilloscope captures, 
as I was able to reproduce them with reasonable accuracy. So, my A-
137 seems to work normally.

Some observations (and some might think nit-picking):

- Of the above mentioned figures "Changing the Symmetry" 
and "Changing the Harmonics" pictures are swapped.

- The above mentioned figures are said to demonstrate: "changing a 
control from low (left picture) to high (right picture)". This 
doesn't necessarily translate to from full counter clockwise to full 
clockwise - at least in my unit.   

- It is best to start experimenting with Harmonics at 9'o clock or 
more. First I assumed, that full counter clockwise was somewhat 
neutral setting.

- The Harmonics control works "a little bit like the resonance 
control of a filter". It doesn't sound at all like a filter though.

- The diagrams in the manual showing some triangle wave folding are 
indeed diagrammatic. I can't reproduce them.

Best regards
Jari Jokinen   

--- In Doepfer_a100@yahoogroups.com, "Tim Stinchcombe" <timothy@...> 
wrote:
>
> Hi Jari,
> 
> At roughly the same settings as you give, my A-137 gives a very 
> similar trace to yours. Because of the 4 stages acting one after 
the 
> other, it is quite hard to see the effect of each stage and/or 
> controls in isolation. I suspect the diagrams in the manual are 
> rather diagrammatic of what is going on, rather than the literal 
> truth, but I'll study the circuit a little, and see if I can answer 
> some of your other questions.
> 
> Tim
> 
> --- In Doepfer_a100@yahoogroups.com, "jalmari3" <jari.jokinen@> 
> wrote:
> >
> > I can't duplicate the folded triangle waveforms shown in the A-
137 
> > manual (chapter 2). The shown waveforms consist of straight 
lines, 
> but 
> > I get rounded waveforms.
> > 
> > Here is an example oscilloscope view:
> > http://www.esnips.com/doc/278f44e2-ce2a-4ff1-8f17-1f7ef5d795d7/A-
> > 137_weirdness_1
> > (I hope the link isn't too long for Yahoo.)
> > The settings are:
> > - All CV inputs at full counter clockwise and unplugged
> > - Input level at 12'o clock
> > - Multiples at 9'o clock
> > - Folding level at 12'o clock
> > - Symmetry at 12'o clock
> > - Harmonics at full counter clockwise
> > 
> > Questions:
> > - Is this the expected output on these settings
> > - Why does a triangle input get rounded?
> > - What settings should give the straight line waveforms shown in 
> the 
> > manual?
> > 
> > 
> > Best regards and thank you for your time
> > Jari Jokinen
> >
>