Ground Loops - Page 2 - diyAudio
Go Back   Home > Forums > Design & Build > Construction Tips

Construction Tips Construction techniques and tips

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 28th February 2014, 02:44 PM   #11
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
I know that, the other channels 0V is providing the 0V return.
  Reply With Quote
Old 28th February 2014, 02:54 PM   #12
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
how far is the ONE return from the TWO Flow routes?

Do not break the signal return route.
__________________
regards Andrew T.
  Reply With Quote
Old 28th February 2014, 02:54 PM   #13
diyAudio Member
 
Join Date: Oct 2012
have you tried grounding to chassis the 0V of the power amp?(Crest series commercial amps used to come equipped with a removable link in multi way systems this allowed lifting or linking)
if indeed both your pre-amp and power amp are floating can you expect it to be quiet?(there has to a ground reference somewhere star-point or otherwise)
  Reply With Quote
Old 28th February 2014, 03:03 PM   #14
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
The PE to Chassis connection is for SAFETY only.

It does not improve sound quality.

If the source to amplifier connections have a grounding loop that is picking up interference, it will still pick up interference whether one, or both, or neither part is connected to PE.
__________________
regards Andrew T.
  Reply With Quote
Old 28th February 2014, 03:06 PM   #15
PMA is offline PMA  Europe
Design engineer, consultant
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Quote:
Originally Posted by KatieandDad View Post
I'm baffled.

If you build a solid amplifier with a star 0V it will work flawlessly.

I've also got a pre-amp with a solid star 0V and it works flawlessly.

Connect the two together and you invariably end up with a loop.

I've got a commercial CD player which I'm not going to modify.

I thought breaking the loops in the pre might do the trick but it hasn't.

The question is where to break the loops.
In case you have two class I instruments (PE connected with signal ground) and single-ended signal interconnections, some degree of hum (even if inaudible but measurable) is inevitable.

Possible cures:

1) fully balanced interconnection
2) single ended interconnection, but with link transformer between preamp and amp
3) only one of the all instruments is in class I
4) isolation transformer for power supply of at least one of the instruments

Any of 4 advices will work.
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 28th February 2014, 03:26 PM   #16
diyAudio Member
 
Join Date: Oct 2012
are the rca (signal grounds)isolated from the chassis earth?

Last edited by turk 182; 28th February 2014 at 03:34 PM.
  Reply With Quote
Old 5th March 2014, 09:38 PM   #17
diyAudio Member
 
Max Martin's Avatar
 
Join Date: Apr 2011
Location: Sweden And Finland
Do i get better SQ with earth ground? Any experience?
  Reply With Quote
Old 6th March 2014, 08:51 AM   #18
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by turk 182 View Post
are the rca (signal grounds)isolated from the chassis earth?
Yes.

But the amplifier needs a voltage reference to tie the output to the input.
This is a single wire reference link.
This link must be close coupled to the wires most sensitive to picking up interference.
__________________
regards Andrew T.
  Reply With Quote
Old 6th March 2014, 05:17 PM   #19
diyAudio Member
 
Speedskater's Avatar
 
Join Date: Sep 2002
Location: Lakewood, Ohio
Quote:
Originally Posted by Max Martin View Post
Do i get better SQ with earth ground? Any experience?
If you mean the connection to Mother Earth, then no improvement to audio quality and sometimes a reduction in quality.
__________________
Kevin
  Reply With Quote
Old 7th March 2014, 06:14 AM   #20
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
Try this. Before you say it, no, it doesn't cause any distortion whatsoever because it never reacts to the signal. It only reacts to common mode signals so the most it can do is fail to reduce a little ground noise (which still leaves you better off than a groundlift resistor would).

This is the kind of thing you want:
http://www.mouser.com/ds/2/355/DS_EV...web19-8801.pdf

The photo has one on the left I got from a projector TV.
Attached Images
File Type: png GroundFaultRejector.png (35.6 KB, 184 views)
File Type: jpg Groundisolate.JPG (233.6 KB, 187 views)

Last edited by keantoken; 7th March 2014 at 06:35 AM.
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Interconnect Ground Cable Ground Loops paulfx Analog Line Level 63 5th November 2014 04:19 PM
ground loops? or lack of ground? how do you tell? turk 182 Construction Tips 9 25th August 2013 03:25 PM
Ground loops antigonos Construction Tips 12 8th August 2013 07:08 AM
Ground Loops 3025826 Car Audio 1 3rd December 2011 09:40 PM
P3A and ground loops biff584 Solid State 5 14th March 2003 03:21 PM


New To Site? Need Help?

All times are GMT. The time now is 11:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2