Help in amplifier grounding - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 16th June 2013, 04:17 AM   #1
diyAudio Member
 
Join Date: Feb 2013
Post Help in amplifier grounding

Hello,

I'm building a gainclone amp and have already the schematic design ready to make the PCB:

Click the image to open in full size.

https://plus.google.com/photos/yourphotos?banner=pwa

but don't know how to deal with the grounds, if it's better to use star grounding or ground plane, and if should I take the entire system (amp supply, OPAMP supply and gainclone amp) together with only one ground or with separate grounds and how to design it in the PCB. Please if someone knows about this topic I would appreciate any advices about it.

Santiago.
  Reply With Quote
Old 16th June 2013, 04:41 AM   #2
djoffe is offline djoffe  United States
diyAudio Member
 
Join Date: Oct 2008
This is a method that worked out well. Go here, and download the assembly manual. The schematic on page 40 and overall wiring diagram on page 41 may give you some good ideas.

Akitika GT-101 Audio Power Amplifier Kit


Also, Douglas Self's power amp book has a couple good sections on grounding.

Here's also a white paper I wrote that covers some issues:

http://www.updatemydynaco.com/docume...lemsRev1p4.pdf
  Reply With Quote
Old 16th June 2013, 07:08 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I can't read values on your schematic.
What is the gain of your inverting chipamp?
Have you deleted the Output Thiele Network and the Output Zobel?
From where does the speaker current demand get satisfied?
No RF filter at the input to the amplifier.

I suggest you build an uncased monoblock and learn from that what you need to include inside your cased multi-channel amplifier.
__________________
regards Andrew T.
  Reply With Quote
Old 22nd June 2013, 05:29 AM   #4
diyAudio Member
 
Join Date: Feb 2013
AndrewT I do have RF filter at the amplifier input, C14 and C13 before the LM3875 input aren't it?? I probably include a zobel network integrated with an active crossover. Thanks.

Santiago.
  Reply With Quote
Old 22nd June 2013, 08:17 AM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by AndrewT View Post
I can't read values on your schematic.......................
No RF filter at the input to the amplifier......................
Quote:
Originally Posted by santi8903 View Post
............. I do have RF filter at the amplifier input, C14 and C13 before the LM3875 input aren't it??...............
I can't read the values !!!!!!

But the point is there is NO RF FILTER at the input to the amplifier. Note INPUT !
__________________
regards Andrew T.
  Reply With Quote
Old 22nd June 2013, 12:34 PM   #6
diyAudio Member
 
lanchile's Avatar
 
Join Date: Sep 2008
Location: AREA 51
Me neither...As hard as I try to find the input cap...I did not see any. it should be in the INPUT=ENTRADA!!! I would put something like 4.7uf cap.
__________________
Make it simple...Make it better!

Last edited by lanchile; 22nd June 2013 at 12:54 PM.
  Reply With Quote
Old 22nd June 2013, 10:33 PM   #7
diyAudio Member
 
Join Date: Jul 2003
Location: .
Isn't C12 (4.7uf), after the buffer, the amp's input cap? I believe you're building this Pedja Rogic Audio Pages - Chip Based Power Amp i.e. Gainclone
I can read the values here, maybe the poster has changed the pic...C13, C14 R16 build an LP filter.
  Reply With Quote
Old 22nd June 2013, 10:48 PM   #8
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
It is vital to separate power supply and audio grounds.
Charging impulses into the smoothing capacitors can modulate 50hz into the ground line and cause havoc.

Run all the audio grounds together then run all the power supply grounds together and connect once at a star ground at an edge connector.
  Reply With Quote
Old 23rd June 2013, 04:09 AM   #9
diyAudio Member
 
Join Date: Feb 2013
Here it is :

Click the image to open in full size.

https://lh6.googleusercontent.com/-9...509-no/amp.PNG

Hope you can see the details, I think as swak that the input cap that you are talking about is C12, and the RF filter are C14 and C13 but the question is how to deal with the grounds, is it better star or ground plane grounding?? and how do I make it in a PCB, I have already designed the following PCB with a star ground but not taking into account the amp ground only for the PSU units (+24, -24 and +15, -15). In this PCB I'm leaving the ground terminals of both PSU to connect it in a star ground with cables later.

Click the image to open in full size.

https://lh3.googleusercontent.com/-1...-no/fuente.png

I appreciate all of your replies. Thanks.

Santiago

Last edited by santi8903; 23rd June 2013 at 04:19 AM.
  Reply With Quote
Old 23rd June 2013, 08:51 PM   #10
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
If you can use a 2-sided PCB, then definitely use ground plane.
  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
Help in amplifier grounding santi8903 Construction Tips 1 16th June 2013 01:29 PM
Grounding a vintage amplifier Karl vd Berg Solid State 6 6th January 2013 12:57 PM
Amplifier grounding Kay Pirinha Instruments and Amps 6 6th June 2012 04:44 AM
pre/amplifier grounding Alkis Tubes / Valves 4 27th February 2005 07:56 PM
Grounding your amplifier? thylantyr Solid State 3 30th April 2003 07:04 AM


New To Site? Need Help?

All times are GMT. The time now is 11:22 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