Doepfer

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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