Changing AC heaters to DC - 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 15th May 2009, 10:57 AM   #1
diyAudio Member
 
Join Date: Jan 2009
Question Changing AC heaters to DC

Is there any way to change heaters from AC to DC without adding a filament tranny ? Can I rectify the AC winding and the drop the voltage back to 6.3V ?
  Reply With Quote
Old 15th May 2009, 11:28 AM   #2
diyAudio Member
 
Join Date: Jan 2002
Location: Tyrone Ga. U.S.A.
You will have to take care of the current rating of the transformer.

If you have a 1A 6.3v transformer and use a full wave rectifier
and a big cap you should get ~ 6.8v dc . 6.3 x 1.41 = 8.82
but you will lose ~2v in the bridge rectifier more important
is that your avaliable current is now ~ .5A not 1A.
  Reply With Quote
Old 15th May 2009, 11:37 AM   #3
diyAudio Member
 
Join Date: Apr 2006
Location: up north
It should not be any trouble. Just recitfy the ac, filter it with a CRC and adjust the resistance to get the right voltage. Be careful to calculate the power dropped over the resistor and make the margin like 50% or so. The resistor will be hot anyhow, but just control that it is not too hot when operating the circuit.

A big powerresistor or one of these resistors that you can mount on a cooling device might be an idea.
  Reply With Quote
Old 15th May 2009, 02:14 PM   #4
diyAudio Member
 
Join Date: Mar 2003
Location: Zürich
Hi Bereanbill

What are you trying to achieve? In some cases making DC out of AC can give more problems than solutions - and one such case is plain rectification and CRC filtering. Have a look at this site

If you are, for example, having HUM problems using AC I don't think you will solve them by simply rectifying and CRC filtering it.
__________________
my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!
  Reply With Quote
Old 15th May 2009, 05:59 PM   #5
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
I use a Shottky diodes to rectify 6.3V getting 8V, or 12.6V getting 16V, then use a N-MOSFET and NPN transistor with one Zener and couple of resistors to regulate it. Why MOSFET? because it works down to zero volt drop-off.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers.” -- Plato, 447-367 BCE
  Reply With Quote
Old 15th May 2009, 06:32 PM   #6
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Here it is:
http://www.diyaudio.com/forums/showt...78#post1828878
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers.” -- Plato, 447-367 BCE
  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
AC wiring heaters, A or B ? zigzagflux Tubes / Valves 10 4th July 2008 09:43 PM
PSU for 12V DC heaters cbutterworth Tubes / Valves 15 9th March 2007 06:25 AM
schematic for 12.6 VDC heaters cbutterworth Tubes / Valves 7 5th March 2007 07:09 PM
KT88 heaters croccodillo Tubes / Valves 48 11th January 2006 08:59 PM
Help with hum in AC heaters HeadSh0T Tubes / Valves 21 27th September 2003 12:40 AM


New To Site? Need Help?

All times are GMT. The time now is 05:43 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