Re: Ground Busses

Henry Pasternack wrote:
> 
> 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.

Don't you mean more hum than silence?
> 
> > Grounding is is tricky and tiresome in inverse pro****tion 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. 

It depends on what knowledge is in the thinker's mind and how good at
thinking they are.

> 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.

Oh my Gord, while your at it, just connect all components up to randomly
chosen circuit points and tube socket pins. 
Avoid all thought, and never check what you are doing.

Turn it on with bravado, and cheer as the smoke rises and parts fry to
death.
But maybe it doesn't hum, so mission accomplished.

That other re-posted advice does ahve lots of good stuff people should
realise 
and practice automatically while thinking about how to make their amp.

So we won't take you seriously always and we will keep smiling... 
> 
> > 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 im****tant 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.

That does take practised skills which are best learnt by trial and error
by diyers in their own shed. All the discussions in the world
about grounding on new groups won't stop diyers getting things wrong a
few times unless they learn,
and some cannot, or simply will not, because its cheaper to go to a tech
person to sort their mistakes.

Even when I point out they ARE ABLE to work it out and learn, and that
they DO HAVE
the time, they won't learn, and won't use the time, and prefer to
do such dumb**** things as attend pubs and watch TV and have reams of
useless small talk with 
others around them. 

So urging Andre, or myself, or to give a diagram of how-to-do yourself 
will have almost zero effect on the hum found in diyer first attempts.

I had to teach myself. And I built test gear for measuring low mV level 
signal volts and currents so I needed to know how to make circuits
quiet.
At first they were hopelessly too noisy, but gradually I got really good
at 
eliminating noise.

It took days and weeks of practice.





> 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. 

Well, starring is the most predictable. It usually gives a fair result.
But you end up using more hook up wire than you'd like to so 
avoiding lengthy wires from PS cap 0V terminals to a point near the
input is investigated.
Finally, the idea of referencing is formed in the diyer's mind, and
ideas about never
allowing a PS supply wire carrying heavy ac or dc to appear commom to
other 0V wires
which may produce some noise at the input.


> 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.

Well, for any given amp, very few variations of the 0V path
will give noise free operation.
determined diyers will find them through their own efforts at
educating themselves on the basics about circuit currents flowing around
the bloody
circuits they are building. But its a big expectation to expect people
to 
prove anything to themselves; many people prefer chocolate to apples,
and bull**** to truth....
>
 
> Of course, being a lying psychopath ****ographic s***bag, 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!  :-)

I have never found you to be a clueless s***bag full of ****o
and don't have the time to determine if its true or not.
****o is art to many folks, unless its ****king 1 year olds, 
and thankfully we don't have images allowed at r.a.t, where no doubt a
small 
minority would make use of the binaries ability to post 
inappropriate images which may be distracting to tube craft.

I find it difficult to think about *** and +700 V at the same time.

If you sent me an image of yourself or even myself ****king Queen
Elizabeth II,
I'd be mildly amused, and know there was no accounting for taste, eh.

I have Nicole K and Kylie M here this minute to mow my lawns
because they get so tired of the work they do.

I also want them to clip the hedges, and they are having a little argy
bargy
about who gets up the ladder, and who holds the ladder steady...

I'll bring them a nice cup of tea when they finish and we'll have a nice
swim in the pool 
after. About 50 laps should tire them out naturally.

r.a.t is democracy without regulation, and its a lot better than
elsewhere....

Patrick Turner.



> 
> -Henry