understanding star grounding

[AndrewT]

Originally posted by davemar73
...................I've tried to scribble this in the diagram.

the lower diagram is correct, but the NFB lower leg also returns to the signal ground.
I now prefer to see the signal ground taken from the RCA barrel/ground tag to the main Audio Ground (Star Ground). This seems to be more resistant to inducing hum/buzz than all the other ways I have tried.

[pacificblue]

Originally posted by AndrewT
some body can't be bothered to read.

That is so true.

Originally posted by d1983
I think that we should star ground the circuit to the NEUTRAL, or return, path. NOT to the ground path.

Originally posted by AndrewT
The Safety Earth normally carries almost zero current, but has to carry Earth Leakage current away safely.

[pacificblue]

Originally posted by AndrewT

That describes double insulated equipment.
We do not have the expertise to design and build and test equipment to this standard.

Designing and building double-insulated equipment is actually easier than earthed equipment. In some German forum it is highly advocated, because of that.

The handicap lies in testing. Mains voltage inside the amplifier (or any other equipment) must remain isolated from all metal parts that can be touched without the use of a tool. And it has to remain that way even during and after a defined mechanical impact, which is what DIYers usally cannot guarantee.

On the other hand, which DIYer can do the obligatory earth resistance and insulation tests to guarantee the safety of his earthed, self-made equipment? Must work carefully and hope for the best outcome.

[bender460]

The Live and Neutral must both be considered as mains and treated as equally dangerous.

I have been following this thread as this is a concern of mine as it should be for all. But I have never hooked my neutral to my chassis. For the very reason quoted above. I have had no issues with hum ever. Mind you I am no expert. I feel as though I build very solid equipment and "I" feel safe in "my" designs. There are extreme "very good to very bad" levels of design, engineering, and execution with DIY. I have personally seen some very scary wiring and chassis layouts. Lets just keep it safe and keep this thread going to educate more people.

[avyrez]

hello

which one is the best variant in interconection



connect the cable shield at one end or both ends

[Anthony C Smith]

many of the ideas in this thread appear lethal!
I went to a very good seminar by Bill whitlock od Jenson transformers at the AES in London, follow this link for the papers:
http://www.jensen-transformers.com/apps_wp.html

the second paper for students is good safe information.
regards

[pacificblue]

Originally posted by avyrez
hello

which one is the best variant in interconection



connect the cable shield at one end or both ends

The best (and correct) variant is to connect the shield on both ends. Leaving the shield disconnected at one end is a means to interrupt hum loops. If you prepare cables like that
a) mark them, so you do not use them for anything else.
b) be aware that you are curing the symptoms instead of the disease.

[avyrez]

ok
i have this image

i the pot attached corectly to the gnd

p.s. sry my bad english

[Speedskater]

Originally posted by Anthony C Smith
many of the ideas in this thread appear lethal!
I went to a very good seminar by Bill whitlock od Jenson transformers at the AES in London, follow this link for the papers:
http://www.jensen-transformers.com/apps_wp.html

the second paper for students is good safe information.
regards

A 2 hour audio version of the Bill Whitlock London seminar is available at:

http://www.aes.org/sections/uk/meetings/a0705.html

You will need to have a printed copy of the "2005 Generic Seminar Template" paper in front of you, just to follow along.

[AndrewT]

Originally posted by pacificblue
The best (and correct) variant is to connect the shield on both ends. Leaving the shield disconnected at one end is a means to interrupt hum loops.

Originally posted by avyrez
i have this image

i the pot attached correctly to the gnd

all four coax to/from the volume pot have the shield connected at just one end.

Pacific,
would you care to comment?