[sdiy] strange grounding problem

Scott Gravenhorst music.maker at gte.net
Tue Jun 21 20:51:43 CEST 2011


dan snazelle <subjectivity at hotmail.com> wrote:
>> 
>> Is your output jack perhaps missing its ground connection 
>(sleeve not connected to anything)? > > 
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>No, it is connected to the same ground as the rest of the NOISEMAKER circuit
>
>All the chips have ground and +v as well

If connecting a wire from modular case (which I assume is connected to modular ground) to
the ground of an external device makes it work, then the ground that should be provided
in the audio cable is not working.  

I would measure the resistance from an internal ground point of the noisemaker to the
sleeve at the end of the cable that plugs into the modular.  It should be very close to
zero ohms.  If it is, then there would seem to be a problem in the modular's jack ground
to it's system ground.

>> 
>>> Well after an hour of going nuts and trying new batteries, I 
>finally figured out that if I run a wire from my Modulars case to 
>the ground lug of the Noisemakers Jack (grnd pin) >> It outputs 
>just fine! (in other words, i have to connect the modular to the 
>Noismaker through ground) > > Synth-diy at synth-diy.org > 
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-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
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