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vcfool
Joined: Jun 19, 2008 Posts: 23 Location: Barcelona
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Posted: Sun Apr 05, 2009 4:32 pm Post subject:
Dual Min/Max Issues |
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Hi,
I built the YuSynth Dual Min/Max. and I had some issues.
First, a little confusion with some resistor values: I used 100K 1% resistors for all the module, included the ones in parallel to make 50K.
From YuSynth's site:
Quote: |
*R8, R12, R17, R29, R33 and R38 are 50k, in fact the PCB has been designed such that you can either use a single 50k 1% resistor or two 100k 1% resistors connected in parallel. |
It clearly doesn't say R16 and R37. But all the resistors in both layout drawings are 100K. And on the parts list there's only 6x 50K (R12, R33 missing) and none of them is separated or marked "*"... so I assumed I could use 100K everywhere and the Max outputs weren't acting as good as expected. After some schematics vs. PCB checking I think R16 and R37 have to be 50K because there aren't holes to mount the parallel 100K ones in there.
I replaced both with 49K9 1% (I didn't have any 50K) and the module began working perfect except...
...when only using Input A.
From YuSynth's site:
Quote: | Besides, as a default the inputs are grounded, therefore if one plugs a signal in an input and nothing in the other, the signals collected at the MIN and MAX outputs are the negative and positive halves of the signal, respectively. |
In my first submodule this is true when using only Input B. When using only Input A I have to manually ground Input B.
In the second submodule I don't have this problem:
The only change I made to the panel wiring is that I omitted the switch and normalled the A/B-Min Output to Input C and the A/B-Max to Input D. So instead of using the switch I patch into one input or the other (I did this because of panel space: The module is a 4HP Eurorack with only 8 jacks.). Anyway, I guess that as both inputs are normalled I don't have the problem: When using only Input C, then Input D is already at 0v (= A/B Max Output). I guess without the normalling then I would have the same problem as on the first submodule... Hope this all makes sense.
So Yves, what does exactly "the inputs are grounded" mean? For now I normalled Input B to ground and everything works great.
Thanks again for another great module! |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Mon Apr 06, 2009 2:56 am Post subject:
Re: Dual Min/Max Issues |
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vcfool wrote: | I replaced both with 49K9 1% (I didn't have any 50K) and the module began working perfect except... |
I'll check that
...when only using Input A.
From YuSynth's site:
Quote: | Besides, as a default the inputs are grounded, therefore if one plugs a signal in an input and nothing in the other, the signals collected at the MIN and MAX outputs are the negative and positive halves of the signal, respectively.
So Yves, what does exactly "the inputs are grounded" mean? For now I normalled Input B to ground and everything works great |
By grounding I mean normalizing to ground that is the switch lug of the jack socket is connected to ground such that when no jack is connected the input is set to 0V, but when one insert a jack the input behaves normaly. But I have just checked the wiring diagram on my site and actually I forgot to draw the normalizing connexions to ground, I will complete the wiring diagram ASAP. Thanks for mentioning the inconsistency.
Quote: | Thanks again for another great module! | Enjoy them _________________ Yves |
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vcfool
Joined: Jun 19, 2008 Posts: 23 Location: Barcelona
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Posted: Mon Apr 06, 2009 5:25 am Post subject:
Re: Dual Min/Max Issues |
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yusynth wrote: |
By grounding I mean normalizing to ground that is the switch lug of the jack socket is connected to ground such that when no jack is connected the input is set to 0V, but when one insert a jack the input behaves normaly. But I have just checked the wiring diagram on my site and actually I forgot to draw the normalizing connexions to ground, I will complete the wiring diagram ASAP. |
This is what I thought and did. But as this is not on the Schematics or the Wiring Diagram I thought that maybe the circuit could be doing this alone, sort of a Pull-Down Resistor thing or something... Maybe I am talking nonsense, my electronic knowledge is really limited. So that's why I asked.
Thanks again! |
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