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Author Topic: Grounding line level shields to rack  (Read 8919 times)

Steve M Smith

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Re: Grounding line level shields to rack
« Reply #20 on: April 11, 2014, 08:47:38 pm »

Maybe you don't have google where you live?

I thought I would ask real experts.


Steve.
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John Roberts {JR}

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Re: Grounding line level shields to rack
« Reply #21 on: April 11, 2014, 09:00:08 pm »

I thought I would ask real experts.


Steve.

"Real experts" have written white papers on the subject, easily found using your favorite search engine. This is kind of old news now so hard to repeat over and over.

JR
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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Ivan Beaver

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Re: Grounding line level shields to rack
« Reply #22 on: April 11, 2014, 09:19:50 pm »

I thought I would ask real experts.


Steve.
And it appears as if the "real experts" agree with the people who"discovered" the issue-found solutions and told the world.

"If it appears as if I can see further-it is because I am standing on the shoulders of GIANTS".

The "geeks" have made life much easier for us :).

It was much harder in years past.  Now almost anybody can get a sound system working.

This is not necessarily a good thing :(
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Stephen Swaffer

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Re: Grounding line level shields to rack
« Reply #23 on: April 11, 2014, 10:24:19 pm »


It was much harder in years past.  Now almost anybody can get a sound system working.


That depends on you definition of "working".

Just curious-but in the absence of access to "mute" an input, wouldn't a dummy "shorting" plug or jack work almost as well?  Essentially giving zero volt DC input?
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Steve Swaffer

Ivan Beaver

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Re: Grounding line level shields to rack
« Reply #24 on: April 12, 2014, 09:39:38 am »

That depends on you definition of "working".

Just curious-but in the absence of access to "mute" an input, wouldn't a dummy "shorting" plug or jack work almost as well?  Essentially giving zero volt DC input?
It is truly sad that these days it seems as if anybody who can make sound come out of a PA is considered an "expert". :(

Just look at all the bad installs out there and all the photos people post in which they are "proud" of what they have done-----------

Yes just shorting the input to a line level device (pins 2 and 3 only) would "mute" it.  Or it coudl be done with a simple switch.

Mic level inputs (especially with phantom power) are a slightly different story-but the same concept applies-
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

duane massey

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Re: Grounding line level shields to rack
« Reply #25 on: April 13, 2014, 03:11:59 am »

It was a multi-pin connector, so a shorting jack would not have worked. The problem was solved by lifting the shield at the outputs and connecting it at the inputs. Simple solution with no action needed by the employees and nothing extra added to the signal chain.
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Duane Massey
Technician, musician, stubborn old guy
Houston, Texas

Kevin Graf

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Re: Grounding line level shields to rack
« Reply #26 on: April 19, 2014, 10:13:42 am »

After 25 posts, no-one  has pointed out that there is no 'ground' connection in a balanced analog interconnect system.

The first paper by Neil Muncy

"Pin 1 Revisited"
 Neil Muncy called our attention to the Pin 1 problem (the improper termination of the shield of audio wiring to the circuit board rather than to the shielding enclosure) in his classic 1994 paper, reprinted in the June 1995 Journal of the AES. When he wrote his paper, most commercially available audio gear had pin 1 problems. It was, indeed, difficult to find equipment without it -- even the most prestigeous consoles had serious pin 1 problems! Over the next decade, the better manufacturers redesigned their products to correct their mistake, but sadly, many have not done so. This is the first installment of a two-part article published in the SynAudCon Newsletter.
http://www.audiosystemsgroup.com/Pin_1_Revisited.pdf

"Pin 1 Revisited -- Part 2"
 This is the second installment of a two-part article
http://www.audiosystemsgroup.com/Pin_1_Revisited_Part_2.pdf

Later it became Audio Engineering Standard 48

AES standard on interconnections
-Grounding and EMC practices-
Shields of connectors in audio equipment containing active circuitry
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Speedskater

ProSoundWeb Community

Re: Grounding line level shields to rack
« Reply #26 on: April 19, 2014, 10:13:42 am »


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