[sdiy] Why dual grounds?

[JH.]

At the GND reference point of your voltage regulators in the PSU.

JH.


----- Original Message ----- 
From: "David Ingebretsen" <dingebre at 3dphysics.net>
To: "'cheater cheater'" <cheater00 at gmail.com>; "'Veronica Merryfield'" 
<veronica.merryfield at shaw.ca>
Cc: "'synth DIY'" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, June 09, 2010 7:12 AM
Subject: Re: [sdiy] Why dual grounds?


> Thanks for the thoughts guys.
>
> Won't these two grounds eventually have to be connected together though? I
> guess that's my main question. I can layout the PCB with separate grounds,
> I'm just baffled as to where/when these two grounds touch each other.
>
> David
>
> ~~ -----Original Message-----
> ~~ From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> ~~ bounces at dropmix.xs4all.nl] On Behalf Of cheater cheater
> ~~ Sent: Tuesday, June 08, 2010 7:29 PM
> ~~ To: Veronica Merryfield
> ~~ Cc: synth DIY
> ~~ Subject: Re: [sdiy] Why dual grounds?
> ~~
> ~~ reference ground vs shield ground?
> ~~
> ~~ On Wed, Jun 9, 2010 at 02:52, Veronica Merryfield
> ~~ <veronica.merryfield at shaw.ca> wrote:
> ~~ > clean and dirty
> ~~ > power and signal
> ~~ >
> ~~ > Probably trying to keep the CV signal clean.
> ~~ >
> ~~ > Double check that there isn't a decoupled, artificial or some other
> ~~ synthesised ground and a real ground.
> ~~ >
> ~~ >
> ~~ > On 2010-06-08, at 5:17 PM, David Ingebretsen wrote:
> ~~ >
> ~~ >> Still working on this Steiner Synthasystem project...
> ~~ >>
> ~~ >> I noticed on the keyboard schematic, Nyle very clearly uses 2 
> grounds.
> ~~ For
> ~~ >> the life of me I don't see why.
> ~~ >>
> ~~ >> In general, why would one want two grounds in a circuit that is not 
> a
> ~~ mix of
> ~~ >> analog/digital and is not outputting signals for audio, just CVs?
> ~~ >>
> ~~ >> Where and how would these two signals come back together. His power
> ~~ supply
> ~~ >> is "nothing special", so to speak. Just one ground from the center-
> ~~ tapped
> ~~ >> transformer, but he clearly runs these ground signals back to the
> power
> ~~ >> supply somewhere.
> ~~ >>
> ~~ >> No other module has two separate grounds.
> ~~ >>
> ~~ >> So, why two grounds on this, but no other module?
> ~~ >>
> ~~ >> I know you need to see the schematic, but I can't publish the thing.
> :(
> ~~ >>
> ~~ >> David
> ~~ >>
> ~~ >> _______________________________________________
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