combine filament winding for rectifier - 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 26th November 2012, 03:07 PM   #1
diyAudio Member
 
Join Date: Nov 2011
Red face combine filament winding for rectifier

hi all, i like your ideas/opinions on my poor-man-solution-idea...

i have a PT here with 3 filament windings.

2x 6.3v @ 2a
1x 5v @ 2a

now i like to use a 5u4g but it needs 3A.

can i just lower the voltage with a chunky resistor on one of the 6.3v windings to about 5v and then put it in parallel with the 5v winding?
  Reply With Quote
Old 26th November 2012, 04:55 PM   #2
diyAudio Member
 
Join Date: Feb 2008
Location: Niederösterreich
NO! The 5v winding is designed for a rectifier tube and in addition to carrying the 5v AC it also carries the rectified high voltage DC. It is insulated differently and sometimes wound differently on the core to account for the H.V. DC it must withstand. The 6.3 volt windings are normally NOT designed for rectifier use. In fact, I dont know of any 6.3v directly heated rectifiers off the top of my head. You may be able to get the 3 amps out of the 2 amp winding without trouble if the rest of the current you are pulling from the transformer is low enough. HTH
  Reply With Quote
Old 26th November 2012, 05:29 PM   #3
diyAudio Member
 
Frank Berry's Avatar
 
Join Date: Sep 2003
Location: Midland, Michigan
Why not change rectifier tubes to something that pulls less filament current?
__________________
Frank
  Reply With Quote
Old 26th November 2012, 07:38 PM   #4
diyAudio Member
 
Join Date: Nov 2011
Thanks for your quick and clear answer!

Is it possible to calculate the extra ampere when not fully using the other windings?

I only plan to use it with 3x 6sl7

And frank, i didnt want to buy new stuff but only use parts i have laying around....
  Reply With Quote
Old 26th November 2012, 07:57 PM   #5
diyAudio Member
 
kstagger's Avatar
 
Join Date: Dec 2003
Location: Grand Rapids
Use a 6X5 one of the 6.3V filament windings. Dirt cheap.

Another option, use a 5AR4, 5V4, or 5Y3 on the 5V filament winding.
  Reply With Quote
Old 27th November 2012, 01:07 PM   #6
diyAudio Member
 
Join Date: Feb 2008
Location: Niederösterreich
With only 3 6SL7 being used i say go for it and use your 5U4. Your transformer should be just fine. I certainly understand wanting to use what you have on hand.
  Reply With Quote
Old 27th November 2012, 04:47 PM   #7
diyAudio Member
 
Join Date: Mar 2011
Location: Jarna
If the total VA of the separate windings is less then the rating of the transformer then no problem.

Just add up the separate windings example:rectifier 5V x 3A = 15VA + 6sl7 6.3V x 0.3A x3pcs =5.67VA.

HT current is the trickier part and depends on type of rectification and if you use regulation.

If it adds up to a number less then the transformer rating you´re safe.

If you overload it a bit and don´t plan to leave it on around the clock you´ll get away with that to.
  Reply With Quote
Old 28th November 2012, 03:51 PM   #8
diyAudio Member
 
Join Date: Nov 2011
Quote:
Originally Posted by flatheadmurre View Post
If the total VA of the separate windings is less then the rating of the transformer then no problem.

Just add up the separate windings example:rectifier 5V x 3A = 15VA + 6sl7 6.3V x 0.3A x3pcs =5.67VA.

HT current is the trickier part and depends on type of rectification and if you use regulation.

If it adds up to a number less then the transformer rating you´re safe.

If you overload it a bit and don´t plan to leave it on around the clock you´ll get away with that to.
also thank you for this explanation.

but all is solved i found a 5Z4 and that tube is within the limits of the transformer...

anyway the transformer is buzzing like mad, even when it's not connected ...

so I'm now try some of the suggestions i found on the forum... we need a good transformer to begin with.....
  Reply With Quote
Old 29th November 2012, 02:44 AM   #9
wa2ise is offline wa2ise  United States
diyAudio Member
 
wa2ise's Avatar
 
Join Date: Apr 2005
Location: NJ
Quote:
Originally Posted by mrneedle View Post

anyway the transformer is buzzing like mad, even when it's not connected ...
Maybe it's just the bolts not tight enough to keep the lams from rattling from the 50 or 60Hz magnetic field. Does the transformer get hot? If so, maybe a shorted turn, if not, try tightening the bolts.
__________________
  Reply With Quote
Old 29th November 2012, 03:31 AM   #10
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
just because it says 5volts at 2A does not mean you can not use it for 3amps, the winding does not stop delivering current at 2.1...try it and most likely you can get away with it...
  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
6.3 filament from 5vac winding tdmur Power Supplies 18 16th January 2011 09:33 AM
300B filament winding center tapped? cjkpkg Tubes / Valves 6 12th September 2010 01:36 PM
Filament winding wire diameter Klimon Tubes / Valves 6 29th March 2010 07:56 PM
Grounding the Filament Winding alexmoose Tubes / Valves 14 8th June 2006 03:39 PM
Help with lowering filament winding voltage. G Tubes / Valves 7 8th September 2003 11:36 PM


New To Site? Need Help?

All times are GMT. The time now is 07:37 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