amp buzzing - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 11th March 2011, 08:14 AM   #1
diyAudio Member
 
Join Date: Apr 2007
Default amp buzzing

Hi I have a problem concerning an amplifier of mine. More specificaly there is a slight periodic buzz comming out of the speaker. The buzz exists with or without connected to the input by the same amount. Is permanent. The amp is monoblock, hast the mains earth connected to the chassi, and I use a 10 ohm resistor with 100nf cap for connecting the chassi to PSU ground. I disconected the mains earth and the noise is the same. Has the point connected the mains earth to be exactly the same withe the end of the loop braker? Total cpacitance is 150mf in a symmetric PSU +/-32v with a 7Hz low pass filter cap-resistor-cap.
I have done the same amp before without this problem, but now I have this problem. There are two different thing though. The first is that in this I have more output devices (mosfets) and the second I noticed a slight difference in the secondaries of the transformer (400VA) in voltages, is about half voltage different. Can this be the root of cause? Also another question is about the orientation of the main connected to the primaries of the transformer. Can the orientation create this buzz. I am asking this because inside my amp I have a second auxiliary transformer with its primary connected (parallel) to the primary of the big one. If I change the "polarities" makes a difference?
Any help it will be welcome.
Thnx
  Reply With Quote
Old 11th March 2011, 12:45 PM   #2
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by kzeprf22 View Post
Hi I have a problem concerning an amplifier of mine. More specificaly there is a slight periodic buzz comming out of the speaker. The buzz exists with or without connected to the input by the same amount. Is permanent. The amp is monoblock, hast the mains earth connected to the chassi, and I use a 10 ohm resistor with 100nf cap for connecting the chassi to PSU ground. I disconected the mains earth and the noise is the same. Has the point connected the mains earth to be exactly the same withe the end of the loop braker? Total cpacitance is 150mf in a symmetric PSU +/-32v with a 7Hz low pass filter cap-resistor-cap.
I have done the same amp before without this problem, but now I have this problem. There are two different thing though. The first is that in this I have more output devices (mosfets) and the second I noticed a slight difference in the secondaries of the transformer (400VA) in voltages, is about half voltage different. Can this be the root of cause? Also another question is about the orientation of the main connected to the primaries of the transformer. Can the orientation create this buzz. I am asking this because inside my amp I have a second auxiliary transformer with its primary connected (parallel) to the primary of the big one. If I change the "polarities" makes a difference?
Any help it will be welcome.
Thnx
Currently I use two bridge rectifiers for the Positive and negative. Do you think that i I use only one with the center tapp as ground will be better?
Any opinions?
  Reply With Quote
Old 11th March 2011, 01:03 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
tell us what transformer you are using?
Show us how you have wired the transformer.
What type of rectifier are you using?
Show us how you have wired the rectifier.
Show us the PSU schematic.
__________________
regards Andrew T.
  Reply With Quote
Old 11th March 2011, 01:36 PM   #4
diyAudio Member
 
Join Date: Apr 2007
Here it the schematic I use?
Attached Images
File Type: jpeg psu.jpeg (97.7 KB, 46 views)
  Reply With Quote
Old 11th March 2011, 02:30 PM   #5
diyAudio Member
 
Join Date: Apr 2007
Also I read in this article
Ground loops, speaker hum and buz from Nico Ras that the voltage differentiation of the two secondaries may lead to buzzin is that correct? And if yes is a way to cure it except buying new transformer?
Anyone with any ideas?
Thnx
  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
Crate guitar amp buzzing MexicanGringo Solid State 1 13th March 2010 04:05 PM
B&K AVR-202i DIY repair possible? Relays buzzing (I think) - otherwise normal? ZepOfLed Solid State 84 8th August 2009 05:46 AM
Buzzing Pre-amp stevebell Solid State 10 12th June 2008 04:26 PM
old hatachi amp buzzing Big_Tires Solid State 1 27th August 2004 08:51 PM


New To Site? Need Help?

All times are GMT. The time now is 02:34 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