[sdiy] Why dual grounds?

[David Ingebretsen]

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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