Doepfer

Some other strange thing I noticed this weekend with the oscilloscope at hand..
I own one a132 and two a130s. The two 130s are of different generations, which I don't 
object to so much.
What I did is the following:

I patch the output of an a118 random voltage into an a172 max/min.
As second input I input a constant voltage from my a176 to make sure that the  max 
output of the a172 puts out only positive values.
This goes into the vca as signal and then I take an envelope as cv input.
This in all the cases delivers a positive voltage output you would say...
However my a130 of the second generation presented a negative output, to my surprise.
All the other mentioned vca's behaved as expected...

Is something wrong with my a130(second generation) or is this an intentional design 
thing..?? (would be strange if you'd ask me)

Greetings,

Ernst

hello ernst,

i had this problem with one of my newer a130's as well.
the output of the a130 was inverted, but besides
this the unit worked as intended.
it appeared to be a wrong wiring on the pcb.
as long as you use the a130 for audio applications,
this is no problem, but it sure is a problem if you
use it to modify control voltages.
dieter fixed this issue on my a130 (i'm not good in
soldering things), i suggest that you contact him directly.

best wishes

ingo



--- In Doepfer_a100@yahoogroups.com, "achtung_999" 
<heinrich.himmelwasser@g...> wrote:
>
> Some other strange thing I noticed this weekend with the 
oscilloscope at hand..
> I own one a132 and two a130s. The two 130s are of different 
generations, which I don't 
> object to so much.
> What I did is the following:
> 
> I patch the output of an a118 random voltage into an a172 max/min.
> As second input I input a constant voltage from my a176 to make 
sure that the  max 
> output of the a172 puts out only positive values.
> This goes into the vca as signal and then I take an envelope as cv 
input.
> This in all the cases delivers a positive voltage output you would 
say...
> However my a130 of the second generation presented a negative 
output, to my surprise.
> All the other mentioned vca's behaved as expected...
> 
> Is something wrong with my a130(second generation) or is this an 
intentional design 

> thing..?? (would be strange if you'd ask me)
> 
> Greetings,
> 
> Ernst
>

Well I use 4 a131s for audio so...
I will contact Dieter.
Thanks!

On 11/2/05, selfoscillate <synaptic_music@yahoo.com> wrote:
>
>  hello ernst,
>
>  i had this problem with one of my newer a130's as well.
>  the output of the a130 was inverted, but besides
>  this the unit worked as intended.
>  it appeared to be a wrong wiring on the pcb.
>  as long as you use the a130 for audio applications,
>  this is no problem, but it sure is a problem if you
>  use it to modify control voltages.
>  dieter fixed this issue on my a130 (i'm not good in
>  soldering things), i suggest that you contact him directly.
>
>  best wishes
>
>  ingo
>
>
>
>  --- In Doepfer_a100@yahoogroups.com, "achtung_999"
>  <heinrich.himmelwasser@g...> wrote:
>  >
>  > Some other strange thing I noticed this weekend with the
>  oscilloscope at hand..
>  > I own one a132 and two a130s. The two 130s are of different
>  generations, which I don't
>  > object to so much.
>  > What I did is the following:
>  >
>  > I patch the output of an a118 random voltage into an a172 max/min.
>  > As second input I input a constant voltage from my a176 to make
>  sure that the  max
>  > output of the a172 puts out only positive values.
>  > This goes into the vca as signal and then I take an envelope as cv
>  input.
>  > This in all the cases delivers a positive voltage output you would
>  say...
>  > However my a130 of the second generation presented a negative
>  output, to my surprise.
>  > All the other mentioned vca's behaved as expected...
>  >
>  > Is something wrong with my a130(second generation) or is this an
>  intentional design
>  > thing..?? (would be strange if you'd ask me)
>  >
>  > Greetings,
>  >
>  > Ernst
>  >
>
>
>
>
>
>
>
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