Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, 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 25th June 2003, 08:30 PM   #1
Account Disabled
 
Join Date: Dec 2002
Default Grounding Issues

Hi,

I am in the process of building some gainclones and a preamplifier. I am having some grounding issues.

My preamp, all 4 amplifiers and power supply are housed in separate chassis.

When I touch the center of an RCA plug that is plugged into an amplifier to the chassis of the preamp, I get a buzz. If I measure from the chassis of the preamp to the air, I get about 5 Volts AC.

When I have everything plugged in, it sounds fine, there is no hum or buzz at all. I would like to get rid of this though as to protect my speakers when I turn it on.

I have nothing connected to the earth connection on my power inlet. When I connect the earth connection to the grounds, the buzz only gets louder.

Enclosed is a schematic of the inside of my power supply.

I am an EE, but I just graduated, and we never really went into anything about grounding issues or ground loops in any of my classes.

I apreciate your help.

Thanks,
Paul Hilgeman
Attached Images
File Type: jpg power supply.jpg (71.3 KB, 204 views)
  Reply With Quote
Old 25th June 2003, 08:40 PM   #2
future is offline future  Brazil
diyAudio Member
 
future's Avatar
 
Join Date: May 2003
Location: Brazil, RGS
Send a message via ICQ to future Send a message via AIM to future Send a message via MSN to future Send a message via Yahoo to future
Are the filter capacitors in each amplifier? They arent in the schematic...
And why the grounds of preamp and amp are separated?
I think this way the return will be the shield of your interconnections.
__________________
what?
  Reply With Quote
Old 25th June 2003, 08:51 PM   #3
Account Disabled
 
Join Date: Dec 2002
Yes,

I put the filter capacitors in each of the amplifier boxes.

I dont know why I dont have them connected.

You are right, that way, the only way that the two would be connected would be through the black wire in the interconnect.

I will give that a shot.

Thank you.

What do I do about the earth connection on my AC Inlet Filter?

-Paul
  Reply With Quote
Old 25th June 2003, 08:58 PM   #4
future is offline future  Brazil
diyAudio Member
 
future's Avatar
 
Join Date: May 2003
Location: Brazil, RGS
Send a message via ICQ to future Send a message via AIM to future Send a message via MSN to future Send a message via Yahoo to future
In electrical equipment the AC ground is connected to the chassis, I dont know if PSU ground is tied together with AC ground.. I would let the grounds separated.
__________________
what?
  Reply With Quote
Old 25th June 2003, 09:22 PM   #5
diyAudio Member
 
Join Date: Aug 2001
Location: Bath, UK
I connect the mains ground (earth) and circuit ground togeter with a resistor and parallel cap network to break any ground loops between sources. You can find details here:
http://headwize2.powerpill.org/proje...meier3_prj.htm

Nice one,
David.
  Reply With Quote
Old 26th June 2003, 09:36 AM   #6
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
can't undersand the use of two rectifers d1,d3 when one should suffice.....
  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
Lions and Tigers and Grounding Problems, Oh My! DoZ Grounding... EchoWars Solid State 37 3rd August 2008 08:50 AM
Grounding Issues Bonce Chip Amps 18 9th June 2006 05:00 PM
LM3875 kit grounding, optimal grounding for separate amps and psu? findog Chip Amps 9 16th May 2005 09:27 PM
Grounding issues miguel2 Chip Amps 5 24th May 2004 06:55 PM


New To Site? Need Help?

All times are GMT. The time now is 11:30 AM.


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