[sdiy] Grounding of inputs/outputs for modules

[Dave Manley]

Time to get out the ohm meter...

:-)

-Dave



-------- Original Message --------
 From: Andre Majorel <aym-htnys at teaser.fr>
 Sent: Fri, Aug 3, 2012 03:37 PM
 To: synth-diy at dropmix.xs4all.nl
 CC: 
 Subject: Re: [sdiy] Grounding of inputs/outputs for modules

>On 2012-08-03 11:40 -0700, David G Dixon wrote:
>
>> > I seem to recall you're a materials type, so pardon the 
>> > question, but doesnt aluminum oxidize?  Can a mechanical 
>> > panel to socket connection be trusted electrically long term? 
>> >   These are dis-similar materials as well, no?
>> 
>> Aluminum oxidizes instantly when exposed to air to form an
>> invisible nanolayer of aluminum oxide, Al2O3.  This oxide
>> layer passivates the aluminum perfectly.  As long as this
>> layer isn't exposed to acid, the underlying aluminum will
>> never corrode.  That is the secret to its widespread use, even
>> in highly oxidizing environments.
>
>But alumina is an insulator. So to make reliable electrical
>contact with aluminium, you must pierce through the alumina
>layer and (this is the difficult bit) somehow keep oxygen out of
>there FOREVER.
>
>> As far as I know, none of the panel-to-jack connections has
>> ever failed in my modular.  If it were a problem, I could
>> easily wire up all the jack rings, but it simply doesn't seem
>> to be necessary.
>
>How would you know if one did ? As all of your modules share the
>same 0 V reference through the power supply, the jack sleeves
>are only used for shielding. Loss of shielding would not be
>obvious thanks to the high levels and low impedances. The Serge
>modular is proof of that.
>
>The only failure you might notice is in the socket that goes to
>your mixing desk. Even then you might not if the ground is tied
>to earth on both sides.
>
>-- 
>André Majorel http://www.teaser.fr/~amajorel/
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