[sdiy-interim] sensible trigger

[Dave Manley]

Try putting a 1K resistor in parallel with the Zener D8.  As designed 
any noise voltage larger than about 700mV will cause the output to 
trigger.  Putting the 1K resistor will divide the input voltage and 
change the trigger voltage up to around 4V.  Increase the resistor 
value, to decrease the input required to cause a trigger. 

-Dave
> I have built a soundlab minisynth
>
> http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html
>
> and the area in the PCB around the "external gate in" circuit seems to be very sensible to proximity:
>
> http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/synthkit_argen_001.gif
>
> Moving my finger near (not even touching) that part of the circuit seems to trigger the AR generator. Can anyone explain what is happening, why and how to fix it? 


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