[sdiy] Buffering 0V when using a pot as a voltage divider?

[Ian Fritz]

At 02:40 PM 6/30/2011, David G Dixon wrote:
>
>
> > -----Original Message-----
> > From: Ian Fritz [mailto:ijfritz at comcast.net]
> > Sent: Thursday, June 30, 2011 10:58 AM
> > To: David G Dixon; 'Harry Bissell'
> > Cc: 'SDIY List'
> > Subject: RE: [sdiy] Buffering 0V when using a pot as a
> > voltage divider?
> >
> > At 11:43 AM 6/30/2011, David G Dixon wrote:
> > > > You mean there realy IS such a thing as a ground loop?
> > > > That's a relief, given the many hours and days I've spent chasing
> > > > them down.  :-)
> > >
> > >Funny, I've never had that problem...
> >
> > Therefore it doesn't exist. LOL!
>
>Maybe I've just been lucky.
>
>However, in all seriousness, one must admit that all of these problems with
>ground stem from creating impedance (dc or ac) on the traces and/or cables
>between the actual ground (at the PSU) and the connection point.  In
>principle, this impedance is zero, and if that were always so, then there
>would never be any problems with ground.  Isn't that right?

Of course. But there are many practical situations where this is not 
possible.  For example long cables in a studio, connecting multiple racks 
and boxes, where you want 100dB S/N.

Ian