Gainclone noise - 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 3rd May 2004, 03:32 PM   #1
tonitze is offline tonitze  Singapore
diyAudio Member
 
Join Date: Feb 2003
Location: singapore
Default Gainclone noise

I've just completed my NIGC 3875. The sound is surprisingly good despite only using 2x12vac 120va trafo which i had in hand for testing. The problem is, I had buzzing noise at the speaker if I put my ear real close to it. The problem went off if I disconnect my RCA connected to my CDP. Is the dc offset of about 25-45mv at the CDP output that may have cause the problem? There no cap at the output of my modified marantz 63 and also my NIGC.
Please help.

Toni.
  Reply With Quote
Old 3rd May 2004, 04:09 PM   #2
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Those DC offset figures are quite good and won't be the cause of the buzzing noise. The mostly likely cause is a bad joint/lose connection somewhere.
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 3rd May 2004, 04:49 PM   #3
GregGC is offline GregGC  Canada
diyAudio Member
 
Join Date: Oct 2003
Location: Toronto
Most likely has to do with the powerlines (220VAC) GND/earth loops. Connect the RCA's and unpug the CDP from the wall outlet. Is the noise there? Is this a new CDP to you or you used it before?


Greg
  Reply With Quote
Old 13th May 2004, 05:49 AM   #4
diyAudio Member
 
Join Date: May 2004
Location: New England, USA
Default Ground Loops

Most hum problems in my experience have been caused by ground loops, which is basically when you have the audio signal ground connected to the earth ground in more than one place. Ideally in your entire audio system / chain, you only want the audio signal ground to be connected to the chassis / earth ground in ONE place. Where that place is, doesn't matter particularly. But you only want one.

If you have all homebuilt equipment, this shouldn't be a problem, because you should know where your grounds are; if you're using pro gear you can probably look in the manual and see whether it's grounded or floating (or look for a 'float' switch somewhere on it). But if it's a mix ... well then you have to play around.

An easy way to eliminate some problems is to make sure that all of your gear is plugged into the same electrical circuit. Even if this means running extension cables (good ones! not cruddy ones where the conductors are all mashed up and shot inside -- the more resistance in the cable, the bigger possible voltage difference you can develop across it) if your equipment is physically separated, at least you'll know that all of your components will have approximately the same ground.

If that doesn't solve anything, then you'll have to start delving deeper, and isolate what component is causing the issue. If you have an oscilloscope, it may be helpful in tracking down these things once you get into the equipment itself.

Good luck!
  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
Low noise transistor and noise figure Real_Macgyver Solid State 28 27th July 2012 10:42 AM
Noise problem with LM3886 gainclone zeus_threat Chip Amps 2 12th April 2008 09:31 PM
(NOISE) Gainclone with bridged LM4780 nickthevoice Chip Amps 13 26th November 2007 04:21 PM
Big noise when turning on gainclone siuguyguy Chip Amps 7 24th June 2006 12:03 AM
My First Gainclone have background noise Felix Chip Amps 22 9th January 2004 09:46 AM


New To Site? Need Help?

All times are GMT. The time now is 01:55 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