Evaluating Tube Diodes as Rectifiers - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs 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

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 6th September 2015, 01:30 PM   #1
diyAudio Member
 
Join Date: Dec 2011
Location: South East Michigan, USA
Default Evaluating Tube Diodes as Rectifiers

I understand that some have used tube diodes as recifiers, even when they are not primarily designed as such. I understand that tube rectifiers are diodes, just specifically purposed to rectify.

What I do not understand is how one evaluates a given tube diode for potential use as a rectifier.

Can anyone shed light on that? Thanks!
  Reply With Quote
Old 6th September 2015, 01:39 PM   #2
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
Forward current rating. Forward voltage drop. Power dissipation. Reverse voltage handling. There is no fundamental difference between a 'diode' and a 'rectifier', just that different valves were designed with different purposes in mind.
  Reply With Quote
Old 6th September 2015, 02:26 PM   #3
diyAudio Member
 
Join Date: Dec 2011
Location: South East Michigan, USA
Quote:
Originally Posted by DF96 View Post
Forward current rating. Forward voltage drop. Power dissipation. Reverse voltage handling. There is no fundamental difference between a 'diode' and a 'rectifier', just that different valves were designed with different purposes in mind.
Ah, so it appears that in some data sheets, some of the necessary information is missing when one tries to repurpose a diode. That makes sense, since it wasn't designed for that reason. Like using a sweep tube as an audio output tube, the values have to be calculated. Is that about right?

So for example, a 6AU4GT. I see PIV and dissipation in the data sheet, but not forward voltage drop or reverse voltage handling. I presume such missing data would have to be calculated?

Thanks!
  Reply With Quote
Old 6th September 2015, 03:57 PM   #4
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
Voltage drop depends on forward current but most sit around 70Volts
__________________
Support for Flying Mole Class D, Allen & Heath, Valve amps, older designs & 2CVs. www.jonsnell.co.uk
  Reply With Quote
Old 6th September 2015, 04:11 PM   #5
diyAudio Member
 
Join Date: Nov 2009
Location: Cortez, CO
There are many damper diodes in Duncan Amps' PSUII; like 6AU4, 6AX5, 6BY5, and the 6CG3. You can try them out there first.
  Reply With Quote
Old 6th September 2015, 08:54 PM   #6
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
Quote:
Originally Posted by Wigwam Jones
I presume such missing data would have to be calculated?
No. It needs to be measured (or calculated by the original valve designer). In some cases the voltage drop is given as a graph of voltage versus current.
  Reply With Quote
Old 6th September 2015, 09:03 PM   #7
Merlinb is offline Merlinb  United Kingdom
diyAudio Member
 
Merlinb's Avatar
 
Join Date: May 2006
Location: Lancashire
Quote:
Originally Posted by Wigwam Jones View Post
So for example, a 6AU4GT. I see PIV and dissipation in the data sheet, but not forward voltage drop
The forward drop is nearly always given on the data sheet in the form of the I/V curve. e.g. the last page of this 6AU4GT data sheet:
http://www.nj7p.org/Tubes/PDFs/Frank...nia/6AU4GT.pdf

The PIV and max peak current are the main things that are normally unknown.
  Reply With Quote
Old 6th September 2015, 09:15 PM   #8
diyAudio Member
 
Join Date: Dec 2011
Location: South East Michigan, USA
So let me ask another way. What would catch your eye when looking at a given tube diode and make you think it might make a good rectifier? And thanks for the replies, everyone!
  Reply With Quote
Old 6th September 2015, 09:20 PM   #9
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
See my post 2.

If you are looking for something other than electronic engineering as a way of choosing rectifiers then I cannot help you.
  Reply With Quote
Old 6th September 2015, 10:10 PM   #10
diyAudio Member
 
Join Date: Dec 2011
Location: South East Michigan, USA
Sorry. Never mind.
  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
any reason to use lower voltage diodes or rectifiers? neutron7 Parts 0 16th December 2009 07:04 PM
Free Diodes/Rectifiers richie00boy Parts 0 26th April 2008 02:56 PM
Component Diodes vs. Bridge Rectifiers dfdye Chip Amps 7 22nd December 2005 06:08 PM
Tube rectifiers NickC Tubes / Valves 32 7th November 2002 10:10 PM


New To Site? Need Help?

All times are GMT. The time now is 10:24 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki