6AU4GTA as High voltage 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 17th December 2003, 05:52 PM   #1
Fuling is offline Fuling  Sweden
diyAudio Member
 
Join Date: Aug 2001
Location: Sweden (Mora)
Default 6AU4GTA as High voltage rectifier

Long story short: 813 SE monoblocks, 900V 110mA B+, hybrid Graetz bridge rectifier, capacitor input filter, what tube to choose: 1 x 5R4 or 2 x 6AU4GTA (damper diodes) per channel??

The low prize, indirect heating and long warmup time of the 6AU4īs seems attractive, but will they survive??
I know a lot of people use them as rectifiers in power amps, but 900V and 110mA is not an easy task for a tube rectifier.
  Reply With Quote
Old 17th December 2003, 06:21 PM   #2
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
I know a lot of people use them as rectifiers in power amps, but 900V and 110mA is not an easy task for a tube rectifier.
According to the RCA datasheet they ought to survive, you're still way below their maximum capability.

Cheers,
__________________
Frank
  Reply With Quote
Old 17th December 2003, 06:39 PM   #3
Colt45 is offline Colt45  Serbia
diyAudio Member
 
Join Date: Feb 2002
Location: Canada
Send a message via ICQ to Colt45
it looks like they should be able to take it.
  Reply With Quote
Old 17th December 2003, 10:02 PM   #4
Fuling is offline Fuling  Sweden
diyAudio Member
 
Join Date: Aug 2001
Location: Sweden (Mora)
Thatīs what I think too.
I particulary like the longer warmup time, that would save me a lot of trouble. Donīt want any cathode stripping in my 813īs, you know...

Now I only have to find locally available octal sockets that can handle the voltage.
  Reply With Quote
Old 17th December 2003, 10:37 PM   #5
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
Now I only have to find locally available octal sockets that can handle the voltage.
Go for the steatite ones.

Cheers,
__________________
Frank
  Reply With Quote
Old 18th December 2003, 10:50 AM   #6
Fuling is offline Fuling  Sweden
diyAudio Member
 
Join Date: Aug 2001
Location: Sweden (Mora)
Shall do. If I can find any, that is.
  Reply With Quote
Old 18th December 2003, 12:56 PM   #7
Fuling is offline Fuling  Sweden
diyAudio Member
 
Join Date: Aug 2001
Location: Sweden (Mora)
Damn it, I just read the last words in the GE datasheet:
(same thing in the Sylvania sheet)
"Operation of this tube as a power rectifier is not recommended"

There is no further explanation why it isnīt recommended?!?
  Reply With Quote
Old 18th December 2003, 01:55 PM   #8
diyAudio Member
 
Gary P's Avatar
 
Join Date: Apr 2002
Location: Portland OR
The 6AU4GTA's in a hybrid Graetz bridge should work good.

I have been running a similar power supply for my active loaded 300B amplifier for 2 years now without any problems. The supply for the active loaded 300B uses a pair of 6AX4GTB's in a hybrid Graetz bridge configuration with a 15uf-10Hy-15uf capacitor input filter. The output is 1000 volts at 140ma. The peak and avarage current specs for the 6AX4GTB is just slightly lower than the 6AU4GTA's.

You can use PSUDII from the Duncan amps page to verify that you are keeping the peak current into the first cap below the 1.1 amp peak limit of the 6AU4GTB.

As for why they recommend that you don't use them for power rectifiers I have no clue... They do a great job in the application.

Gary
  Reply With Quote
Old 18th December 2003, 02:47 PM   #9
Fuling is offline Fuling  Sweden
diyAudio Member
 
Join Date: Aug 2001
Location: Sweden (Mora)
Ok, letīsee...
I canīt figure out how to make a hybrid Graetz bridge in PSUD2 ???
  Reply With Quote
Old 18th December 2003, 02:49 PM   #10
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
It may be possible, but I suggest:
Run the sim with SS, then with valves.
Interpolate the results.
  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
need a high amperage, low voltage rectifier... Stuart Easson Parts 5 5th November 2004 05:02 AM


New To Site? Need Help?

All times are GMT. The time now is 10:17 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2