Using common mode chokes in filament supply. - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

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

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 9th December 2002, 02:01 PM   #1
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Default Using common mode chokes in filament supply.

How do you apply a common mode choke in a filament supply? Do you put one in series with each 6.3 volt filament or in parrallel with all of them. Also what size do you use? My guess is that you would put them in series with each filament. But that is just a guess.

G
__________________
Gavin
  Reply With Quote
Old 9th December 2002, 02:27 PM   #2
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hi..a common mode filter..as I see it is just a choke in the positive AND the negative voltage rail... With the difference that they are connected to the same core.

I use a mains filter ..commonly used before the transformer in ..say a cd player.. but instead I use it in the filament of my driver tube...

So each "inductor" will be in series on each rail..but the two inductors will be "parallel"..

Hope this helps..

Regards,
Bas
  Reply With Quote
Old 9th December 2002, 02:30 PM   #3
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Default Should look like this..

.
Attached Images
File Type: gif cmf_figure_1.gif (2.7 KB, 326 views)
  Reply With Quote
Old 9th December 2002, 02:37 PM   #4
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Thanks Bas. Is there a certain value that you prefer to use for filament supplies? Also, would putting a capacitor across the line at each filament in addition to the CMC would help also. Thanks for the info.

G
__________________
Gavin
  Reply With Quote
Old 9th December 2002, 02:42 PM   #5
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hi G,

Nope I use any value really. And yes, putting a cap a cap across the filament would indeed help. I also use this..

But better still would be to use 2 caps...one on each leg of the filament...and each one to ground...this would be the "second" part of your filter..

So that you would have a LC filter on each leg..

Cheers,
Bas
  Reply With Quote
Old 9th December 2002, 02:50 PM   #6
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Thanks for that Bas. I was looking for an image to post with an explanation earlier tonight before I went out, but it looks like you beat me to it.

Cheers
  Reply With Quote
Old 9th December 2002, 02:56 PM   #7
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Yeah, the image is a little confusing though if you look at the arrows.. :-)


R U busy building a tube amp? Or tweaking an existing one?
  Reply With Quote
Old 9th December 2002, 02:58 PM   #8
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
O.. hi Brett..

I thought G posted that.. :-)

By the way..do you think it is worthwile doing this..on an IDH tube..I did it on my 6n1p driver..but I am to lazy to undo it to check if it makes a difference..

Cheers,
Bas
  Reply With Quote
Old 9th December 2002, 03:10 PM   #9
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Quote:
Originally posted by G
Is there a certain value that you prefer to use for filament supplies?
G,

I buy mine from an industrial parts supplier, and get the biggest value CM choke I can, usually in the order of a few mH or more depending upon the current rating. Larger 100mH are about $5 and I'm going to add some of these to my MC phono stage when it's apart next.

As noted elsewhere, a CM choke won't reduce hum, unless it's a couple of orders of magnitude larger, and probably more expensive too.
  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
common-mode chokes jarthel Tubes / Valves 6 11th February 2008 03:31 PM
Common-mode EI PS Chokes rdf Tubes / Valves 14 17th June 2007 08:36 AM
Common Mode Chokes for Heater Supplies ppereira Tubes / Valves 7 29th January 2006 01:45 PM
Source for common mode chokes abj1 Tubes / Valves 7 24th June 2005 06:31 AM
Common mode chokes Dr.H Digital Source 1 24th July 2002 04:47 PM


New To Site? Need Help?

All times are GMT. The time now is 08:36 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