Re: Ground Busses

"Patrick Turner" <info@[EMAIL PROTECTED]
> wrote in message
news:47CBD98A.6004F916@[EMAIL PROTECTED]
>
>
> 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.

In my experience, the layout and ground scheme can make or
break and amp.  The schematic only tells half the story.  As far
as tube amps go, careful examination of mil spec equipment, or
units built for studio use, can tell you a lot.  The bean-counters
had a lot less influence over their design than they would have had
over equipment made for the domestic market.
>
>> 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.

ISTM there are two ways to learn about this kind of thing.
You can do it the hard way, and make the same mistake over and
over again, gradually implementing changes which lead to improvement,
or: You can listen to people with experience, and gain info from
books and looking at real-world examples.  I have done some of
both.  But still I have a lot to learn.

> 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.
>
It's taken me forty years - so far:-)>

Iain