Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Loudspeaker noise from 300B
Loudspeaker noise from 300B
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 24th September 2007, 10:06 AM   #1
mavallarino is offline mavallarino  United States
diyAudio Member
 
mavallarino's Avatar
 
Join Date: Oct 2006
Default Loudspeaker noise from 300B

Hello to all,

I have a strange problem. I have already tried to search for this exact problem with little results.

There is a small speaker buzz arriving from both channels of my 2A3/300b amplifier.

There is no mains power to amplifier (and there is still this buzz).
The grounding looks okay (There wasn't this problem before).

No lights are present, no cellular telephones, WiFi is disconnected etc... No AC connected...

Is there a problem with the ouput transformers? How can I check without sophisticated equipment?

Please ask questions because it is difficult to write all important details. Thank you for your help.

Kind regards to all!
  Reply With Quote
Old 24th September 2007, 04:00 PM   #2
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Loudspeaker noise from 300B
Try disconnecting the mains and all signal leads from the amplifier.

Next try disconnecting the speakers from the amplifier and shorting the speaker cables together at the amplifier. (No, I'm not kidding) If you still hear a buzz that indicates that you have a strong magnetic field in that area of your listening room. This indicates that your speaker wiring is acting as a loop (equivalent to a single turn on a transformer) and picking up induced voltages. Suspect nearby electrical appliances (fluorescent lights, big transformers used for low voltage lighting e.g quartz halogen lamps, hot water heater, high current mains wiring, etc..) I have run into this problem a few times over the years with highly efficient speaker systems.

If the pick up does turn out to be magnetic twisting the speaker cable conductors (making a twisted pair) should help.
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote

Reply


Loudspeaker noise from 300BHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
DIY loudspeaker vs. factory built loudspeaker keyser Multi-Way 130 14th June 2016 10:21 PM
Low noise transistor and noise figure Real_Macgyver Solid State 28 27th July 2012 09:42 AM
Noise - 6J5 - 71a -300B amp hal3101 Tubes / Valves 14 3rd November 2008 04:42 PM
FS: for 300B (JE Labs 300B SE) builders cartman Swap Meet 2 29th October 2008 01:13 PM
* 35 watt * 300B SE = super 300B + Class A2 rick57 Tubes / Valves 4 13th July 2005 04:18 PM


New To Site? Need Help?

All times are GMT. The time now is 03:20 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki