Doepfer

I took a look at your video: you cannot measure the peak voltage of an ADSR
with a digital multimeter ! For this e.g. an oscilloscope is required. With
the digital multimeter an average value over a period of time is measured
(depending upon the measurement cycle of the meter in question).

Best wishes
Dieter Doepfer


> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups.com]
> Gesendet: Dienstag, 7. November 2017 16:34
> An: Doepfer_a100@yahoogroups.com
> Betreff: RE: [Doepfer_a100] Envelope Generator Problem
>
>
> Thanks for doing this. That's good news... in a way.  Now the question is,
> why is this happening?
>
> I think I will have to empty one of the cases and build a very simple
> synthesizer with minimal parts and see what happens.
>
> Thanks again!
> Scott
>
>
>
> -----Original Message-----
> From: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups.com]
> Sent: Tuesday, November 7, 2017 10:26 AM
> To: Doepfer_a100@yahoogroups.com
> Subject: AW: [Doepfer_a100] Envelope Generator Problem
>
> Hello,
>
> I took an A-140 and cannot confirm this behaviour. That's what I did:
>
> - wait about 10 seconds
> - permanent high signal to the gate input
> - measuring the ADSR output (especially the peak voltage) with
> oscilloscope
> -> peak is about +8.4V
> - replacing the permanent gate signal by an LFO rectangle with about 10 Hz
> - measuring the ADSR output (especially the peak voltages) with
> oscilloscope
> -> all peaks are about +8.4V
>
> I could detect any difference in the peak level of the "first" envelope
> (permanent gate) and the peak levels when the A-140 was triggered by the
> LFO.
>
> Best wishes
> Dieter Doepfer
>
>
>
> > -----Ursprüngliche Nachricht-----
> > Von: Doepfer_a100@yahoogroups.com
> > [mailto:Doepfer_a100@yahoogroups.com]
> > Gesendet: Dienstag, 7. November 2017 04:11
> > An: Doepfer_a100@yahoogroups.com
> > Betreff: [Doepfer_a100] Envelope Generator Problem
> >
> >
> >
> >
> >
> > Hi Folks
> >
> > Sorry to post this again but my whole modular synth is unusable until
> > I fix this problem so I still need help.
> >
> > The problem: All of my envelope generators do the same thing - When I
> > play a note they peak at a certain voltage, lets say 5 volts. But when
> > I play a second note that peak rises to 6 volts.
> > And in some cases when I play 16th notes it rises even more.
> >
> > So when I connect the output of an envelope generator to a VCA the
> > first note I play is always MUCH quieter than every following note.
> >
> > I have 3 Doepfer LC9 cases with various modules in each. This behavior
> > is consistent in all three boxes with all of my envelope generators.
> >
> > The modules are:
> > Doepfer A-140 (3 of these)
> > Doepfer A-143-2 quad
> > Roland 540
> >
> > Also, the all 4 of the envelopes in the A-143-2 do not actually
> > sustain. The voltage constantly falls when a note is held, even when
> > the sustain level is set to maximum. That is a separate problem but I
> > thought I'd mention it.
> >
> > Also, for some reason the release time of the Roland 540 is only
> > 2 seconds (even on the Slow setting) when plugged into any VCA,
> > however when it is plugged into the Roland filter the release time is
> > much longer. Another weird problem but I thought I'd mention it in
> > case it was an important clue.
> >
> > I have tested the output of all of the envelopes with both analog and
> > digital volt meters to confirm the behavior.
> >
> > At this point I'm not sure what to do to fix this. I guess the first
> > question is:  Is this the way these envelopes are supposed to work?  I
> > have owned analog synthesizers since 1978 and own a lot of them right
> > now and not a single one has this behavior.
> > Other than when using velocity sensitivity, every note played is
> > exactly the same volume.
> >
> > Is this a known issue? Are there combination of modules that can cause
> > this to happen? Could it be the power supplies? I have moved the
> > modules around and found the behavior is the same regardless of how
> > many modules (or which ones) are in a case.
> >
> > What kind of troubleshooting can I do? With only a trigger voltage
> > being sent to the Envelope module I don't think there could be
> > anything else interfering but I'm looking for any clues at all, even
> > the most obvious ones that I may have overlooked.
> >
> > I did a video to show the problem:  https://youtu.be/x8_1ZnmPWLo
> >
> > Thanks for any ideas anyone might have!
> >
> > Scott
> >
> >
> >
> >
> >
> >
>
>
>
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> ------------------------------------
> Posted by: "Scott Rogers" <scott@scottfromcanada.com>
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