Ground Busses
Andre Jute wrote:
A star ground is just a circular bus or a very short bus.
Not really, ANDRE. A star ground is the abstract notion of a purely
equipotential (equal voltage) single point connection that eliminates
ground loops by reducing the resistance of the common ground bus to
zero. It's impossible to achieve in practice, though, and trying to
take the approach too literally is likely to cause more harm than
good.
Grounding is is tricky and tiresome in inverse proportion to the
amount of thought you give it.
I would say the opposite is true. The less you think about grounding,
the less tricky it seems. With no thought at all, it becomes as simple
as pie. Or fruit tart, for that matter. Just connect all the ground
connections together any way you like, and don't worry. It's only
when you start to think about it that it truly becomes tricky.
Here you can see my star point [URL deleted].
You may be able to see it, but to my eyes the picture is impossibly
tiny to reveal any useful details. But, you know I have this problem
with photographs.
Most schematics don't tell you enough about earthing. Here, for
instance: [URL deleted]. I've shown the star earth being implemented
but have not said anything about connecting the case to earth.
Attempting to connect all the grounds together like that, willy-nilly,
is not the right approach. That's because in practice it's nearly
impossible to achieve a true equipotential connection for all those
wires. Also, there are other performance issues having to do with
all those long ground connections running about the amplifier.
... I showed all the 0V connections in order, with a note saying
"mind the order of the grounding connections", and two people wrote
me letters saying that DIYers are not idiots who need their hands
held.
Then the DIYers were idiots, because the subject is quite worthy of
elaboration. The problem I see with everything you say here is that
you fail to address the most important meat of the problem, which is
precisely how to determine the "order of the grounding connections"
and how this translates into a practical wiring and ground layout.
My opinion on this subject is there are many ways to wire an amplifier
to minimize hum and noise. Star grounding (and its variants) and
bus wiring are two common solutions. Rather than posting fuzzy
pictures and vague generalities, if you would like to help your
readers, you should teach them the principles involved (you do
know them, right?) so they can work out the optimum grounding
scheme for each project by themselves.
Of course, being a lying psychopath pornographic scumbag, I may
not really know what I'm talking about! Feel free to ignore
everything I say. In fact, I strongly urge you to do so! :-)
-Henry
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