GU-50 output trafo - 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 10th May 2007, 12:04 PM   #1
diyAudio Member
 
croccodillo's Avatar
 
Join Date: Mar 2005
Location: Bergamo
Default GU-50 output trafo

Hi all,

I read everything I found about GU-50 tubes, here on the forum and on the net (I'm thinking to use them for my new amplifier).
The problem is that it is not clear to me the actual outrput impedance of such a tube: I found reference to a 10K, 5K, 2K transformers, and I don't know which is the right value.
The datasheet I found do not report any value for the output impedance, nor any graph for triode-strapped condition.
Can you help me?

Thanks in advance,
Giovanni
__________________
In Nomine Libertatis Vincula Edificamus,
In Nomine Veritatis Mendacia Efferimus.
  Reply With Quote
Old 10th May 2007, 06:43 PM   #2
Colt45 is offline Colt45  Serbia
diyAudio Member
 
Join Date: Feb 2002
Location: Canada
Send a message via ICQ to Colt45
What topology are you planning on using them in?
  Reply With Quote
Old 10th May 2007, 06:49 PM   #3
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Hi Giovanni!

For pentodes (regulated G2):

GU-50 100W output and power transformers

For triodes with 400V plate voltage you'll probably need 2-3K CT
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 11th May 2007, 07:09 AM   #4
Tweeker is offline Tweeker  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Cincinnati, Ohio
Triode curves.
Attached Images
File Type: jpg russian gu50 triode curve.jpg (53.2 KB, 234 views)
__________________
Be sure your foil hat has a good low impedance ground.
  Reply With Quote
Old 11th May 2007, 07:22 AM   #5
diyAudio Member
 
croccodillo's Avatar
 
Join Date: Mar 2005
Location: Bergamo
Hi, thanks for the answer.
The topology will be a parafeed SE amplifier.
I would like to use two or more paralleled GU-50 as output tube, driven with a High Voltage CCS (not decided yet if use a solid state one or a tube one).
Output trafo will be a toroid (I found a good -and cheap- manufacturer here in Italy).
THIS is a draft of the idea I have.
The output tubes will have an idle voltage of about 300V (low, I know), while the CCS will work between 200 and 0V, with a current of 100mA.
I'm thinking to use two paralleled GU-50 tubes also for the upper CCS.
If I can keep the output impedance as low as 1K, I can have about 20W of RMS output power...

I don't know if use the GU-50 in pentode mode, triode-strapped mode, enhanced triode or whatever else comibnation of grid1, 2, 3 voltages...

My idea was to use them as triode as output tubes, and use pentode mode (if I will ever use tubes) for the CCS.

Ciao,
Giovanni
__________________
In Nomine Libertatis Vincula Edificamus,
In Nomine Veritatis Mendacia Efferimus.
  Reply With Quote
Old 11th May 2007, 07:31 AM   #6
Boeing is offline Boeing  Japan
diyAudio Member
 
Join Date: Apr 2007
Hi ! I am using my GU 50 SE tube amp with 3.5KOhm OPT, at 330V plate voltage. It sounds beautiful .
Regards.
  Reply With Quote
Old 11th May 2007, 07:37 AM   #7
diyAudio Member
 
croccodillo's Avatar
 
Join Date: Mar 2005
Location: Bergamo
Thanks boeing for the feedback; some more information?
Do you use a single tube? How is it connected (triode, pentode, what else)?

Ciao,
Giovanni
__________________
In Nomine Libertatis Vincula Edificamus,
In Nomine Veritatis Mendacia Efferimus.
  Reply With Quote
Old 11th May 2007, 08:55 AM   #8
Boeing is offline Boeing  Japan
diyAudio Member
 
Join Date: Apr 2007
Hi Croccodillo ! My tube amp is triod connection. My OPT has Ultra linner terminal, but I have never tried it.
Regards.
  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
VALVOLOZZO triode amp with toroids output trafo...help me zig290682 Tubes / Valves 14 11th June 2009 06:50 PM
Got a big output trafo I want to use. lawbadman Tubes / Valves 27 29th October 2008 04:14 PM
Output trafo for WE-91 L'Audiophile amp? WE91 Tubes / Valves 81 19th March 2007 11:34 AM
PP Output Trafo Measurement jkeny Tubes / Valves 8 6th February 2007 08:29 AM


New To Site? Need Help?

All times are GMT. The time now is 05:30 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