Help needed on tube rectification. - 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 8th March 2004, 01:45 PM   #1
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
Default Help needed on tube rectification.

Hi everyone,

I have always loved the tube rectifier, but no knowledge of how to design a PSU based on it. Solid state powersupplies are very simple to design, but tube powersupplies have always baffled me.

The formula for calculating the DC produced through the tube confuses me the most.

Could someone explain more to me and also provide me with the formulas? Thanks a million! I have referred to many tube rectification schematics but they don't seem to have much relation with each other.
  Reply With Quote
Old 8th March 2004, 02:09 PM   #2
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hopefully someone that has a "theory background" will help you out soon.

In the meantime, have you heard of Duncan's Power supply simulator?

In case you have not ...it is very easy to use and free.

http://www.duncanamps.com/psud2/index.html


Good luck,
Bas
  Reply With Quote
Old 8th March 2004, 02:24 PM   #3
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
Quote:
Originally posted by Bas Horneman
Hopefully someone that has a "theory background" will help you out soon.

In the meantime, have you heard of Duncan's Power supply simulator?

In case you have not ...it is very easy to use and free.

http://www.duncanamps.com/psud2/index.html


Good luck,
Bas

Tried it with schematics I referred to and it seems to produce different voltages as stated in the schematic. Confuses me all the time.

Thanks for the luck, I need it.
  Reply With Quote
Old 8th March 2004, 05:19 PM   #4
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Try to measure the resistance of you power transformer and choke. And all other parts. And enter them.

The simulator is never far off in my experience.

Cheers,
Bas
  Reply With Quote
Old 9th March 2004, 08:11 AM   #5
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
Quote:
Originally posted by Bas Horneman
Try to measure the resistance of you power transformer and choke. And all other parts. And enter them.

The simulator is never far off in my experience.

Cheers,
Bas

I'm sending in my order for custom wound transformers, so i would like to learn the theory before getting practical.

Cheers!
  Reply With Quote
Old 9th March 2004, 09:28 AM   #6
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Quote:
referred to and it seems to produce different voltages as stated in the schematic. Confuses
How big are the differences?
  Reply With Quote
Old 10th March 2004, 06:32 AM   #7
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
Quote:
Originally posted by Bas Horneman


How big are the differences?

About double of what is stated on the schematic.
  Reply With Quote
Old 10th March 2004, 07:12 AM   #8
SHiFTY is offline SHiFTY  New Zealand
diyAudio Member
 
SHiFTY's Avatar
 
Join Date: Jul 2002
Location: New Zealand
Rough rule of thumb:

A traditional transformer and fullwave rectifier (ie two diodes with a grounded centre tap) will give you about 1.2 times the AC voltage with a CLC filter. (ie 350-0-350 AC -> approx 420VDC) A diode bridge will give you about double that.

Under load, the voltage may shift around quite a bit, a bigger transformer gives better regulation. In PSU designer, make sure you have a current load that simulates the amps total current draw.

A "modern" tube rectifier like a GZ34 will give you a higher voltage than an older type like a 5U4, and also give a nice slow warm up.

Use a choke of 5-10H or more to give the best results.

Be careful of the value of the first capacitor. GZ34 will take 50uF or so, but 5U4 will not take more than a few uF.

Tell us more about the parts you have and what you are trying to build.
  Reply With Quote
Old 10th March 2004, 07:26 AM   #9
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
Quote:
Originally posted by ShiFtY
Rough rule of thumb:

A traditional transformer and fullwave rectifier (ie two diodes with a grounded centre tap) will give you about 1.2 times the AC voltage with a CLC filter. (ie 350-0-350 AC -> approx 420VDC) A diode bridge will give you about double that.

Under load, the voltage may shift around quite a bit, a bigger transformer gives better regulation. In PSU designer, make sure you have a current load that simulates the amps total current draw.

A "modern" tube rectifier like a GZ34 will give you a higher voltage than an older type like a 5U4, and also give a nice slow warm up.

Use a choke of 5-10H or more to give the best results.

Be careful of the value of the first capacitor. GZ34 will take 50uF or so, but 5U4 will not take more than a few uF.

Tell us more about the parts you have and what you are trying to build.

When you say diodes I take it taht you are referring to tube diodes, right?

Considering between 6X4 and GZ34 as the rectifier. I'm building a PSU for my 6SN7 preamp, wired SRPP. Need about 250V to 300V for it, in stereo.

Will have the coils(trannie, choke) custom made and buying the components I dont have. (caps, resistors..etc)

Thank you!
  Reply With Quote
Old 10th March 2004, 01:37 PM   #10
w00t is offline w00t  Singapore
diyAudio Member
 
Join Date: Aug 2003
Location: Singapore
BTW, the voltage on the transformer in PSU Designer II is the voltage across the 2 extreme ends of the trannie or with reference to CT? Thanks.
  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
Tube vs. Semiconducter rectification Richard Ellis Tubes / Valves 44 14th August 2008 04:20 AM
Tube rectification for SS cicuit dsavitsk Power Supplies 6 16th July 2005 11:04 AM
SS vs. Tube Rectification (and chokes)? Sherman Tubes / Valves 48 6th December 2004 10:48 PM
solid state Vs Tube Rectification sandy Tubes / Valves 3 3rd September 2004 04:20 AM


New To Site? Need Help?

All times are GMT. The time now is 02:42 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