Earth again Earth again - diyAudio
Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Earth again
Earth again
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th July 2005, 06:36 PM   #1
Pbassred is offline Pbassred  United Kingdom
diyAudio Member
 
Pbassred's Avatar
 
Join Date: Nov 2003
Location: N London
Send a message via MSN to Pbassred
Default Earth again

I make only a slightest appology for asking this but its an issue of safety, and I alway tell people "ask the stupid questions first and often". This shoulb be in a F.A.Q. somwhere.

Am I correct in assuming that I should connect the mains earth to the chassis of my amp?
Is it correct that I should also connect it to the screen of my signal wire?
__________________
Jeeees! I only asked
https://www.facebook.com/dave.potter.5815
  Reply With Quote
Old 5th July 2005, 08:18 PM   #2
moamps is offline moamps  Croatia
diyAudio Member
 
Join Date: Oct 2002
Location: Croatia
Here is what I think about the subject if you are interested.

http://www.diyaudio.com/forums/showt...ighlight=earth

post 10

Regards,
Milan
  Reply With Quote
Old 5th July 2005, 08:21 PM   #3
Nelson Pass is offline Nelson Pass  United States
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Earth again
I always "earth" the chassis of the amp. Then I form a connection
between the circuit ground and the chassis one of 4 ways:

1) Piece of wire

2) Power resistor

3) Power thermistor

4) Power diode bridge.

The last three offer some barrier against ground loops, but
should be designed so that the AC line fuse fails long before
they do.

  Reply With Quote
Old 5th July 2005, 08:38 PM   #4
12 Cents is offline 12 Cents  Germany
diyAudio Member
 
12 Cents's Avatar
 
Join Date: Nov 2004
1. Yes, the chassis of your amp should be earthed.

2. Normally not. In balanced connections it may be a good idea, I don't know.

Edit: Some quick people here, the numbers refer to the initial question.
  Reply With Quote
Old 5th July 2005, 08:53 PM   #5
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
> ...I should connect the mains earth to the chassis of my amp?

Under many electrical codes, it is required. A strict reading of NEC calls for EVERY BIT of metal in the house to be Grounded. UL rules lead to metal cases on plug-in appliances being either solidly-grounded or a fail-safe "Double Insulated" scheme to ensure line-voltages can't appear on the outside of the device.

> Is it correct that I should also connect it to the screen of my signal wire?

Maybe.

Since you can usually touch it, Code requires bonding.

BUT. The Line is a potent source of garbage. Big garbage on the shield means small garbage in the signal. And if, as in most hi-fi, the "shield" is really also the Signal Common, garbage comes through directly.

However, if you float the audio system, the main outside interference (in most locations) is the Earth and the Power Lines. Totally floating operation can drown in buzz.

Also, if you have multiple grounds, you can get induced currents flowing in them, and inducing garbage voltages.

So we usually ground the audio common, but with great care.

If you don't know better, bond your DC power supply common to the Line Ground/Earth with a 10 ohm 1 watt resistor. This will suck-out most of the problems of totally-floating operation while also reducing ground-loop currents to very-small, and keeps the residual away from input stages. Much more elaborate grounds are sometimes needed, but very rarely.
  Reply With Quote
Old 5th July 2005, 11:37 PM   #6
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Extremely good advice, particularly PRR. My experience precisely.

Cheers,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 6th July 2005, 12:42 AM   #7
mastertech is offline mastertech  Australia
Banned
 
Join Date: Mar 2005
Location: Australia
all machines with metalic chassis/enclosures
must be earthed ground for the sake of owner safety
i have come across some japanese consumer electronic products
either with fuly metalic chassis or top half which have not been
earthed ground, for safety they rely on a clamp with short leads
close to final connection,how safe is that compared to earthed ground
machines is for safety experts and regulation authorities to judge

cheers
  Reply With Quote
Old 6th July 2005, 12:59 AM   #8
amplifierguru is offline amplifierguru
Account Disabled
 
Join Date: Aug 2004
Location: Earth
For safety there is no question that the exposed metal chassis and heatsinks should be earthed/grounded to the mains ground.

With respect to signal earths, I always connect the supply ground to the chassis via paralleled 10R IW resistor and back to back 1A diodes.

Works for me.

Cheers,
Greg
  Reply With Quote
Old 6th July 2005, 02:41 AM   #9
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
This is exactly what I do and what Rod Elliot recommends in his article on grounding. He also suggests a 100nF capacitor as well but that's probably secondary.
  Reply With Quote
Old 6th July 2005, 02:52 AM   #10
Steve Eddy is offline Steve Eddy  United States
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by jaycee
This is exactly what I do and what Rod Elliot recommends in his article on grounding. He also suggests a 100nF capacitor as well but that's probably secondary.
What the capacitor does is keep the impedance between the supply ground and the safety ground very high at power line frequencies, but much lower at RF so that the chassis can better serve its function of RF shielding.

se
  Reply With Quote

Reply


Earth againHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hi All in the EARTH stoN_Cold Car Audio 0 30th December 2006 05:29 PM
Car amp earth sidewz Car Audio 0 20th April 2004 10:47 PM
Earth Connection Sherman Chip Amps 16 16th April 2004 12:59 PM
How on earth...? Nuuk Chip Amps 4 6th April 2004 01:55 PM
Should I come down to Earth ? Prof Chip Amps 19 12th June 2003 02:05 PM


New To Site? Need Help?

All times are GMT. The time now is 01:04 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki