To ground or not to ground - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

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 January 2015, 12:13 AM   #1
diyAudio Member
 
Join Date: Jun 2014
Default To ground or not to ground

Doing a bit of work on my Kenwood KD-3070 turntable. Removed the old lamp wire AC cord and replaced it with a nice more robust 3 prong equivalent. Also used the opportunity to do a full cleaning and setup of the TT's internals/externals.

As of now I do not have the ground wire of the new AC cord connected, it is floating. I have read about ground loops being induced if the ground is used. All my equipment connects to a power strip. Am I ok to connect the ground?

Pics for reference
Click the image to open in full size.
Inside, note stock power cord on far right

Click the image to open in full size.
New power cord installed, note green ground wire floating in the middle
  Reply With Quote
Old 28th January 2015, 12:51 AM   #2
Jsixis is offline Jsixis  United States
diyAudio Member
 
Join Date: Feb 2011
Location: Columbus Ohio
I would guess no. I bought a Teac R2R and its power cord had been replaced and it hummed no matter how I connected it till I removed the ground wire.
Doesn't the turntable have a ground wire? One that your suppose to hook up to the reciever?
If you have 2 grounds then you will definitely get a hum.
__________________
I know nothing, so learning is really awesome.
  Reply With Quote
Old 28th January 2015, 01:14 AM   #3
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
It depends.
If you have equipment before the amplifier that is earthed then you don't need a earth connected.
On the other hand if you are using a floating MP3 player or similar then the amplifier needs earthing.
That has been my experience.
__________________
PCBCAD51 pcb design software. http://murtonpikesystems.azurewebsites.net/
  Reply With Quote
Old 28th January 2015, 10:33 AM   #4
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Surely a turntable has two grounds? One is a safety ground, to the incoming supply ground (if available). If built to Class II spec then this ground is unnecessary and must be omitted; otherwise it must be present.

The other is a signal ground, to the phono preamp. These two grounds are not connected together at the turntable.
  Reply With Quote
Old 28th January 2015, 12:38 PM   #5
diyAudio Member
 
Join Date: Jan 2008
Rule I always follow is to NOT ground a unit which originally has floating ground.
  Reply With Quote
Old 28th January 2015, 12:39 PM   #6
diyAudio Member
 
Join Date: Jun 2014
Quote:
Originally Posted by DF96 View Post
Surely a turntable has two grounds? One is a safety ground, to the incoming supply ground (if available). If built to Class II spec then this ground is unnecessary and must be omitted; otherwise it must be present.

The other is a signal ground, to the phono preamp. These two grounds are not connected together at the turntable.
This is a 70ís turntable, originally used a 2 prong AC cord.
I am a guitar player and build/repair tube amps. So whenever I see a 2 prong AC cord I want to upgrade it to a modern 3 prong for safety reasons. I am just wondering if I can ground the AC cord for safety reasons and not have a impact on sound...
It appears all the PSU ground, headshell grounds, etc. Go to one common ground point in the turntable chassis.
  Reply With Quote
Old 28th January 2015, 01:42 PM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
If the Mains powered equipment meets ClassII (double insulated) standard then leave it as is.

If it is built to ClassI standard then it NEEDS a safety Earth.
The biggest metal component should be connected to the Mains PE wire.

All other conductive parts should be electrically connected to that protected part of the Chassis. Here is the problem !!!!!
Adding a connection from the Safety Earth to the metal arm will almost certainly LOOP into the signal ground/return of the output to the pre-amp.

If one is lucky, then there may be electrical isolation between the arm metal work and the signal return.

I would suspect that most mains powered turntables are built to ClassII standard to avoid the need to connect the arm into the Mains PE wire.
__________________
regards Andrew T.
  Reply With Quote
Old 28th January 2015, 02:04 PM   #8
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
In my opinion it is best to use Class II (double isolated) equipment throughout in the audio chain, or maximum one Class I. Or two Class I power amplifier mono blocks at the end. In this case all previous equipment should be Class II (as they normally are). Most frequent exceptions are tape decks and I wonder how is ground loop avoided at them?
  Reply With Quote
Old 28th January 2015, 05:37 PM   #9
vulejov is offline vulejov  Serbia
diyAudio Member
 
vulejov's Avatar
 
Join Date: Aug 2010
Quote:
Originally Posted by Willi Studer View Post
Rule I always follow is to NOT ground a unit which originally has floating ground.
Cubie - small F5 variant with GR grade JFETs and LatFETs

If you ground it there will be no floating ground..
  Reply With Quote
Old 29th January 2015, 09:02 AM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by vulejov View Post
Cubie - small F5 variant with GR grade JFETs and LatFETs

If you ground it there will be no floating ground..
took me to post97
Quote:
Vule, please don't spoil this rare philosophical moment - let us indulge in its revelational depths...
__________________
regards Andrew T.
  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
shield ic chip at analog ground or digital ground? KevinLee Digital Source 2 17th July 2012 12:15 PM
Parallel LM3886, input ground, power ground, safety resistor and oscillations. markiemrboo Chip Amps 5 9th August 2007 03:50 PM
DC filament ground and high voltage ground mikeyho Tubes / Valves 0 15th September 2005 05:52 PM
Chassis Ground = Circuit Ground --> Problems? rhildenbrand Pass Labs 5 23rd April 2004 01:08 AM
does connecting mains ground with circuit ground create a ground loop? jarthel Everything Else 0 25th June 2003 12:55 PM


New To Site? Need Help?

All times are GMT. The time now is 04:58 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright ©1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2