grounding questions...

[Tony Allgood]

Hi all,

Roel>The CV inputs of VCO, VCA, etc, should they default to ground?

This is what I would recommend, especially for CV pitch inputs to VCOs.
If you use a normalised socket like the Switchcraft 112s, this is a
breeze. However, make sure they ground to the module 0V not the module
casing since this may be at another potential.

I would not ground your module jack lugs by the modules OV supply. I
have a special ground/earth bus for this job only. It only grounds the
socket lug and casing nothing else. This way you get the cables shielded
both ends and no current loops. All the module's OV are star earthed to
main power supply. In my present system both ground types are connected
to the ground of the power supply at the power supply.

You may prefer making the screening ground common to mains earth, or via
a low value resistor/diode combination. See the archives for more on
this. It must be said that in the UK all metal cases/parts that are
touchable by the user have to be directly connected to earth in any
mains powered unit. You could then connect your module 0V to earth via
100R resistor.

Regards,

Tony Allgood  Penrith, Cumbria, UK

Modular synth circuits, TB303 clone and Filter Rack

http://www.techrepairs.freeserve.co.uk/projects.htm