PP GU50 triode strapped project - Page 4 - 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 12th May 2012, 02:14 PM   #31
jane is offline jane  Norway
diyAudio Member
 
jane's Avatar
 
Join Date: Jul 2004
Location: Norway
Quote:
Originally Posted by LAZAROIU View Post
Raa = 4000ohmi, is seen and calculated as an OT like normal and then will distribute a 1/4 anode and katod tasks for the two final floor tubes.
Be sure OT is running PERFECT!
But everyone thinks it sees fit, so I was thinking and it seems that everything is OK!
I'm not sure I understand you, but:
In a normal push-pull stage each output tube sees 50% of the windings that is Raa/4 (in class B). In a unity stage each tube sees 100% of the windings (anode + cathode windings) that is Raa. If you want the tubes to see the same reflected load in a unity stage as in a normal push-pull stage the unity-OPT should be Raa/4 (where Raa is the anode to anode load in a normal pp stage).

Jan.
__________________
Life is hard - Then you die.
  Reply With Quote
Old 12th May 2012, 02:44 PM   #32
diyAudio Member
 
Join Date: Nov 2008
Location: 135200
Quote:
Originally Posted by jane View Post
I'm not sure I understand you, but:
In a normal push-pull stage each output tube sees 50% of the windings that is Raa/4 (in class B). In a unity stage each tube sees 100% of the windings (anode + cathode windings) that is Raa. If you want the tubes to see the same reflected load in a unity stage as in a normal push-pull stage the unity-OPT should be Raa/4 (where Raa is the anode to anode load in a normal pp stage).

Jan.
Can we not understand, but I did a test simulation result for LTC and have equivalent Raa 3700ohmi results of pictures, but the schematic is made ​​and practical.
Of course I made a proposal, but you can improve all.Proposal another configuration transformer, with some drawings and can get along better.
LTC simulation images below to Raa = 3700 ohm (equivalent), everyone on this forum can verify this.
Thanks for your attention!
Attached Files
File Type: pdf analiza Forier distorsiuni.pdf (10.1 KB, 79 views)
File Type: pdf FFT .pdf (18.6 KB, 57 views)

Last edited by LAZAROIU; 12th May 2012 at 02:46 PM.
  Reply With Quote
Old 12th May 2012, 03:51 PM   #33
diyAudio Member
 
Join Date: Nov 2008
Location: 135200
Quote:
Originally Posted by LAZAROIU View Post
Can we not understand, but I did a test simulation result for LTC and have equivalent Raa 3700ohmi results of pictures, but the schematic is made ​​and practical.
Of course I made a proposal, but you can improve all.Proposal another configuration transformer, with some drawings and can get along better.
LTC simulation images below to Raa = 3700 ohm (equivalent), everyone on this forum can verify this.
Thanks for your attention!
rectify and apologize:
it is: Fourier analysis,not Forier.

Bode diagram ... and if it is useful ...
Attached Files
File Type: pdf Bode diagram.pdf (17.6 KB, 67 views)

Last edited by LAZAROIU; 12th May 2012 at 03:57 PM.
  Reply With Quote
Old 12th May 2012, 03:55 PM   #34
diyAudio Member
 
Join Date: May 2007
Hey LAZAROIU,
Why not share your *.asc with the rest ofus?
  Reply With Quote
Old 12th May 2012, 04:05 PM   #35
diyAudio Member
 
Join Date: Nov 2008
Location: 135200
Quote:
Originally Posted by revintage View Post
Hey LAZAROIU,
Why not share your *.asc with the rest ofus?
Please escuse me, i dind't understood you're question. Do you want a scheme in format ".asc", for a simulation in LTC? or do you want something else?

Last edited by LAZAROIU; 12th May 2012 at 04:07 PM.
  Reply With Quote
Old 12th May 2012, 04:08 PM   #36
diyAudio Member
 
Join Date: May 2007
Quote:
Originally Posted by LAZAROIU View Post
Please escuse me, i dind't understood you're question. Do you want a scheme in format ".asc", for a simulation in LTC? or do you want something else?

Exactly as I said. But is not important as I am almost ready with the LTSpice drawing. I can share that one instead. What is the primary inductance of your OPT?
  Reply With Quote
Old 12th May 2012, 04:22 PM   #37
diyAudio Member
 
Join Date: Nov 2008
Location: 135200
Quote:
Originally Posted by revintage View Post
Exactly as I said. But is not important as I am almost ready with the LTSpice drawing. I can share that one instead. What is the primary inductance of your OPT?
I will post the scheme in format ASC, without considering it perfect. It depends on the models of the components from LTC librarys. If you think there is something to change, please feel free to share. (of course in format ASC)
Attached Files
File Type: asc GU50 UTC 20W-PREAMP TUBURI RUSESTI varianta DIY .asc (8.1 KB, 114 views)
  Reply With Quote
Old 12th May 2012, 06:32 PM   #38
diyAudio Member
 
Join Date: May 2007
Hey,

Have corrected a few errors and used Koren and Bench´s models that are reliable.

You will have to work with the working points as it´s not up to your specs.

The concertina must have higher Ua to work properly, it now is in the ballpark of 50V.

I am not fully aware of how the SRPPs with 27k on top works? Also they seem to run on very low current, 1,5mA.

The GU50 ran on ca 40mA but should maybe run ca 100mA/tube, A knows.

The transformer inductances where much off. Use 2.5H for the primaries and .08H for the secondary to get 4k/8. Gives you a low 40H primary but that´s good enough for initial sims. If you go for 5.55H, secondary should be 0.18H. 5.55/0.048 is ca 15k/8. But maybe strange things happen when you go with cathode windings?

Also some Spice-commandos should be adjusted.
Attached Files
File Type: asc gu50t.asc (8.3 KB, 65 views)

Last edited by revintage; 12th May 2012 at 06:34 PM.
  Reply With Quote
Old 14th May 2012, 08:10 AM   #39
diyAudio Member
 
FrançoisL.'s Avatar
 
Join Date: Apr 2008
Location: Annecy/FRANCE
Send a message via Skype™ to FrançoisL.
Quote:
Originally Posted by Vincent77 View Post
François: Lazaroiu's schematic uses a special transformer with windings for cathode feedback, I don't know if Lundahl makes such transformers... There are some very good such toroidal transformers made by Menno van der Veen: Specialist Range Output Transformers
Vincent,

Thanks for the link.
Now, I must say, and maybe it's a novice reaction, that to purchase "special" transformers for a project that I don't know if it will please me or meet my expectations worries me a little bit.........
But maybe I should not?
__________________
François.
  Reply With Quote
Old 14th May 2012, 10:36 AM   #40
diyAudio Member
 
Join Date: Aug 2008
Quote:
Originally Posted by jane View Post
Here is my version of GU-50 PP triode:

Click the image to open in full size.

Single ended driver stage and cathode windings to keep the output impedance low (enough) without the means of gNFB.
Should be finished during the summer..
Wow that should take care of the drive problem! I am eager to see your measurements when it is done!
  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
OPT PP for GU50 Triode ? pwan Tubes / Valves 0 12th March 2011 11:30 PM
6JC6 triode strapped? Bing Yang Tubes / Valves 4 21st February 2009 09:59 PM
PP-Triode , PP-UL , PP-Pentode-strapped-as-Triode percy Tubes / Valves 23 22nd January 2007 12:36 AM
Recommendations needed for designs of PP pentode strapped as Triode percy Tubes / Valves 24 22nd October 2004 09:03 PM
E180F triode-strapped. jim Tubes / Valves 15 16th September 2003 11:00 AM


New To Site? Need Help?

All times are GMT. The time now is 05:04 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