[sdiy] Why dual grounds?

Andre Majorel aym-htnys at teaser.fr
Wed Jun 9 18:13:25 CEST 2010

On 2010-06-09 17:36 +1000, Stewart Pye wrote:

> Since many of the modular synth standard power supply connectors
> (MOTM, Oakley, Blacet etc) have two ground wires, is one of these
> used for a "clean" ground and the other "dirty ?

No. Usually, both ground pins are shorted. This is true for all
MOTM, Tellun, Blacet, Patchell and Ruberto boards I've seen.

On Oakley boards, all signal and power ground traces go to the
ground pin that's on the +15 V side. The ground pin on the -15 V
side is only used to ground the sleeve contacts of the jacks. It's
not clean vs. dirty or signal vs. power, it's frame ground vs.

More modules should use the 6-pin power connector and power LEDs
etc. off the +5 V line. If nothing else, it would mitigate the
derating of the power supply caused by asymmetrical loads (most
modules draw more current from the positive rail).

André Majorel http://www.teaser.fr/~amajorel/

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