Class A Push Pull with 6L6GC - 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 3rd December 2007, 01:50 AM   #1
diyAudio Member
 
Join Date: Nov 2006
Default Class A Push Pull with 6L6GC

Hey all, I want to design an amp (guitar amp) that uses 6L6GC in push pull, but runs class A. Cathode Bias.

I have scoured the books to try and find how to calc OT impedance, cathode current and plate voltage but not much luck. Can someone give me an idea of how to calc these values?

thanks
d1
  Reply With Quote
Old 3rd December 2007, 02:05 AM   #2
diyAudio Member
 
astouffer's Avatar
 
Join Date: Jun 2004
Location: Pittsburgh, crumbling wasteland
Try looking up the classic Williamson amp. I think the article goes as far as showing how to wind the transformers.

http://www.clarisonus.com/Archives/A...0Amplifier.pdf
  Reply With Quote
Old 3rd December 2007, 04:05 AM   #3
diyAudio Member
 
Join Date: Nov 2006
Interesting read, but does not discuss calculating load impedances for push-pull class a, nor calculating cathode current or plate voltage.

Any other suggestions?
  Reply With Quote
Old 3rd December 2007, 05:15 AM   #4
diyAudio Member
 
Miles Prower's Avatar
 
Join Date: May 2005
Location: USA
Blog Entries: 6
Default Re: Class A Push Pull with 6L6GC

Quote:
Originally posted by d1camero
Hey all, I want to design an amp (guitar amp) that uses 6L6GC in push pull, but runs class A. Cathode Bias.

I have scoured the books to try and find how to calc OT impedance, cathode current and plate voltage but not much luck. Can someone give me an idea of how to calc these values?
If you can't get this from the spec sheet (See: Frank's) then you'll have to use a loadline to determine the values for Q-Point and load. I did a mini-tutorial on that Here
__________________
There are no foxes in atheistholes
www.dolphin-hsl.com
  Reply With Quote
Old 3rd December 2007, 12:31 PM   #5
diyAudio Member
 
aletheian's Avatar
 
Join Date: Apr 2004
Location: Philly
Default Re: Re: Class A Push Pull with 6L6GC

Quote:
Originally posted by Miles Prower


If you can't get this from the spec sheet (See: Frank's) then you'll have to use a loadline to determine the values for Q-Point and load. I did a mini-tutorial on that Here

HEY!!! Frank's is back up!! I yanked it from my bookmarks a few months ago because i thought it was a gonner. You just made my day.
__________________
Heghlu'meH QaQ jajvam!
  Reply With Quote
Old 4th December 2007, 12:58 AM   #6
6f6 is offline 6f6  United States
diyAudio Member
 
Join Date: Oct 2006
I you want to learn how to create a loadline, determine impedance, and determine distortion for an amp, go to Steve Bench's site.
  Reply With Quote
Old 4th December 2007, 01:02 AM   #7
diyAudio Member
 
Join Date: Jul 2003
Location: Ann Arbor, MI
hey-Hey!!!,
For Class A PP, just take the SE/single tube operating point, and double the load. Say fora 2k5 SE, go to 5k. In Class A, each side sees half the plate-to-plate load.
cheers,
Douglas
__________________
the Tnuctipun will return
  Reply With Quote
Old 4th December 2007, 02:04 AM   #8
diyAudio Member
 
aletheian's Avatar
 
Join Date: Apr 2004
Location: Philly
Quote:
Originally posted by Bandersnatch
hey-Hey!!!,
For Class A PP, just take the SE/single tube operating point, and double the load. Say fora 2k5 SE, go to 5k. In Class A, each side sees half the plate-to-plate load.
cheers,
Douglas

Very true. D1camero, if you want to go that route, RCA's sheets and test data pages have operating points and very detailed info for A1 SE pentode mode in both fixed and cathode bias between 200v and 350v, and a little additional chart for A1 PP pentode mode at a few more op-points... should be close enough to whatever you need.
__________________
Heghlu'meH QaQ jajvam!
  Reply With Quote
Old 4th December 2007, 01:08 PM   #9
diyAudio Member
 
Join Date: Nov 2006
Hey all, thanks for the help. I looked at Steve's site and others. FWIW Here is one that nicely walked me through the process:

http://www.freewebs.com/valvewizard
  Reply With Quote
Old 4th December 2007, 08:35 PM   #10
diyAudio Member
 
aletheian's Avatar
 
Join Date: Apr 2004
Location: Philly
Quote:
Originally posted by d1camero
Hey all, thanks for the help. I looked at Steve's site and others. FWIW Here is one that nicely walked me through the process:

http://www.freewebs.com/valvewizard

A friend of mine runs that site. He is a good guy, and I think he has a few more how-to articles planned for the site, so bookmark it.
__________________
Heghlu'meH QaQ jajvam!
  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
2A3s in push pull; class A Sir Trefor Tubes / Valves 44 31st May 2013 03:37 AM
40W class A push pull amp with JJ 2A3-40w possible? 3nity Tubes / Valves 18 26th May 2010 11:05 PM
Class A push-pull Nikolas Ojala Pass Labs 5 24th August 2009 12:58 PM
Class A, push pull amp using transistor space2000 Solid State 18 7th August 2008 02:53 PM
EL34 Push Pull in Class A arnoldc Tubes / Valves 29 17th May 2006 11:52 AM


New To Site? Need Help?

All times are GMT. The time now is 05:15 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