Pentode curves for GU 50 SE amp with 700V B+ - Page 2 - 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 15th January 2013, 04:11 PM   #11
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by usbekhistan View Post
wavebourns link.The amp is working at all

It is right-handed triode connection. But the same trick with local feedback from anode of output pentode to anode of driver pentode can be used, to get pentode power and even better than triode linearity and even lower than triode output impedance.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 15th January 2013, 08:40 PM   #12
Ejam is offline Ejam  Australia
diyAudio Member
 
Join Date: Aug 2004
Location: Queensland
Default A little confused

Waveborn

A little confused, are you talking about operating a GU50 as a right handed triode with plate to plate feedback or your Pyramid VII push pull circuit with GU50 as a pentode and plate to plate feedback?

Also your link does not work.

A further question if I may, you make reference to the GU50 operating best at high voltages, can you elaborate further on this. Would be much appreciated.
  Reply With Quote
Old 15th January 2013, 10:03 PM   #13
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Ejam;

if you look at curves you will see why I make reference to the GU-50 operating the best at high voltages. Pay attention at curves bent on the left side, i.e. at higher currents/lower voltages. It is obvious.

Negative feedback linearizes any tube no matter works it in SE or PP amp.

Let me attach the picture here if it does not show for some IP addresses.
Attached Images
File Type: png Gubernator_Mk_6b_3.png (18.2 KB, 154 views)
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 16th January 2013, 02:58 AM   #14
Ejam is offline Ejam  Australia
diyAudio Member
 
Join Date: Aug 2004
Location: Queensland
Wavebourn

Yes, thank you for pointing out the obvious, but from 400V up the curves are essential flat with little variation. Granted the closer to 400V, a steeper loadline is needed to avoid the lower voltage curvature. What I was alluding too, and perhaps did not express it rather well, was that in several previous posts you recommend 800V. So why not 700 or 600V with a steeper loadline (accepting less power of course) ? Is there something special about 800V or as they say is it a sweet spot for the GU50 ?

Ejam
  Reply With Quote
Old 16th January 2013, 05:30 AM   #15
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Why 800? I attached the picture especially for you, did you ever look at it? It is 500V there.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 16th January 2013, 05:40 AM   #16
diyAudio Member
 
Join Date: Feb 2010
Default Look

at this,it was discussed at another thread here on diyaudio.http://i19.photobucket.com/albums/b1...gu50semine.gif
I used similar feedback option for me,of course my driver tube is a 6J9P.The whole thing is working for some days now very well (with 700 Volt B+).I can switch the voltage doubler off,so i can operate with 350 B+ as well.
  Reply With Quote
Old 17th January 2013, 08:02 PM   #17
diyAudio Member
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Quote:
Originally Posted by usbekhistan View Post
at this,it was discussed at another thread here on diyaudio.http://i19.photobucket.com/albums/b1...gu50semine.gif
I used similar feedback option for me,of course my driver tube is a 6J9P.The whole thing is working for some days now very well (with 700 Volt B+).I can switch the voltage doubler off,so i can operate with 350 B+ as well.
Which one sounds better to you?
  Reply With Quote
Old 18th January 2013, 06:37 AM   #18
diyAudio Member
 
Join Date: Feb 2010
Default I guess

you mean the voltage.Of course 700 volt sounds better
  Reply With Quote
Old 20th January 2013, 08:57 AM   #19
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally Posted by Wavebourn View Post
Ejam;

if you look at curves you will see why I make reference to the GU-50 operating the best at high voltages. Pay attention at curves bent on the left side, i.e. at higher currents/lower voltages. It is obvious.

Negative feedback linearizes any tube no matter works it in SE or PP amp.

Let me attach the picture here if it does not show for some IP addresses.
Is there an IRF equivalent for the mosfet FQPF3N80C ?
  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
Simple SE GU-50 Einric Tubes / Valves 49 3rd June 2012 09:13 AM
Building new GU-50 stereo amp... Wavebourn Tubes / Valves 129 4th August 2011 04:26 PM
GU-50 PP amp project - Any favs? DaveInVA Tubes / Valves 7 31st March 2010 04:03 PM
Derive Triode Curves from Pentode Curves? dsavitsk Tubes / Valves 3 14th May 2007 06:10 PM
A small no-fuss pentode/pentode SE amp Tubes4e4 Tubes / Valves 13 1st January 2006 05:16 AM


New To Site? Need Help?

All times are GMT. The time now is 08:53 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