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

Class D Switching Power Amplifiers and Power D/A conversion

Basic ground and earth questions
Basic ground and earth questions
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
Thread Tools Search this Thread
Old 27th March 2007, 06:03 PM   #1
dublin78 is offline dublin78  United Kingdom
diyAudio Member
Join Date: Mar 2006
Location: Cheshire
Default Basic ground and earth questions

I am putting together in one case, a Marantz CD63SE, a Monica2 DAC, a line level preamp, a Charlize T-amp, and an SMPS (to power dac, pre and power amps).

My question is this (very obvious and basic if you know): Are the line level signal grounds meant to be all connected together (between CDP and dac, between dac and preamp, between preamp and poweramp). Also are these to be connected to the 240v earth that is used by the SMPS and CDP?

What potential problems are there?
How do I avoid ground loops?
Any tips greatfully received.

I am sure that this is covered elsewhere, but simple questions are hard to search and find.
  Reply With Quote
Old 28th March 2007, 05:39 AM   #2
j.videtich is offline j.videtich  United States
diyAudio Member
Join Date: Sep 2006
If all of the inputs are differential, there won't be any noise and signal grounds definitely should be tied together. I would assume signals are either internally tied to earth ground or intentionally floated and would not attach them externally.
  Reply With Quote
Old 28th March 2007, 06:28 AM   #3
AndrewT is offline AndrewT  Scotland
Join Date: Jul 2004
Location: Scottish Borders
is the CDP earthed with a three core cable?

The safety earth system is there solely to protect the user in the event that a fault develops in the equipment. It is NOT there to make the audio system quieter nor work better. In many instances the safety earth makes the performance of the audio system worse.

The audio ground in the equipment is part of the flow and return circuit both internally and to other connected equipment. This flow and return is fundamental the the way electricity flows around a circuit (note; circuit). The audio will work perfectly well without any connection to the safety earth.

There is a very important condition.

All exposed conductive parts MUST be connected to the safety earth.
This over-rules the audio requirement to float the ground system completely separate from the safety earth IF there are any metal parts that can be touched by the user.

I recommend a disconnecting network between the safety earth and the floating audio ground rather than a direct ultra low resistance connection.
The disconnecting network can consist of any combination of the following :-
Power resistor,
Power diode bridge,
Power thermistor.

Additonally a high frequency capacitor may make the system quieter. A switch to short across this network to effect a direct connection could be fitted (this is the ground lift switch occassionally found on equipment- the ground lift switch MUST NOT BREAK the connection between safety earth and audio ground).
regards Andrew T.
  Reply With Quote


Basic ground and earth questionsHide 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
chassis ground vs. earth ground avid Chip Amps 4 10th November 2006 12:56 PM
ground and earth senderj Tubes / Valves 17 10th April 2006 04:47 AM
signal ground and earth ground ttray321 Tubes / Valves 9 3rd May 2005 03:14 AM
question on ground/earth diodes Rudy Pass Labs 1 10th May 2003 03:12 AM
Earth/Ground Loops JohnClark Tubes / Valves 2 14th November 2001 12:49 AM

New To Site? Need Help?

All times are GMT. The time now is 01:53 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio