Single Ended Pentode Spud and Feedback - 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 4th October 2009, 04:24 AM   #1
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Default Single Ended Pentode Spud and Feedback

Usually, at least in guitar world, in a single ended pentode amp, the feedback return is to the cathode of the driver. But, in the case of a spud amp, where there is no driver, any suggestions on how to add some feedback? Any ideas?
Attached Images
File Type: gif SEP.gif (3.3 KB, 508 views)
  Reply With Quote
Old 4th October 2009, 04:47 AM   #2
ddd is offline ddd  Bulgaria
diyAudio Member
 
Join Date: Oct 2005
Location: Sofia
You can ground the cathode resistor through the second coil or part of it. Add a cathode capacitor to increase the gain of the stage as well.
Mind the direction of the coil.

Last edited by ddd; 4th October 2009 at 04:55 AM.
  Reply With Quote
Old 4th October 2009, 07:04 AM   #3
diyAudio Member
 
Miles Prower's Avatar
 
Join Date: May 2005
Location: USA
Blog Entries: 6
If you have just the one stage, then there's just one choice: Anode Follower.
__________________
There are no foxes in atheistholes
www.dolphin-hsl.com
  Reply With Quote
Old 4th October 2009, 01:07 PM   #4
Yvesm is offline Yvesm  France
diyAudio Member
 
Yvesm's Avatar
 
Join Date: Jul 2004
Location: Ardeche
Pardon my ignorance but ... what is "spud" for ?
  Reply With Quote
Old 4th October 2009, 03:53 PM   #5
diyAudio Member
 
Michael Koster's Avatar
 
Join Date: Jan 2008
Location: Eureka, CA
Quote:
Originally Posted by Yvesm View Post
Pardon my ignorance but ... what is "spud" for ?
An amp with only one tube is a "one-tuber"...

A potato is a "tuber"...

Slang for potato is "spud"...

Therefore a one-tube amp or one-tuber is a spud.

makes sense, right???
  Reply With Quote
Old 4th October 2009, 06:30 PM   #6
Yvesm is offline Yvesm  France
diyAudio Member
 
Yvesm's Avatar
 
Join Date: Jul 2004
Location: Ardeche
TNXTU
Was searching for an acronym.
I would never be able to find that by myself !

Yves.
  Reply With Quote
Old 4th October 2009, 06:53 PM   #7
diyAudio Member
 
Join Date: May 2007
"Anode follower" is what we call inverse-feedback or Schade when talking transformer-coupled pentodes. Makes the pentode act more triode-like.

What tube?
  Reply With Quote
Old 4th October 2009, 08:47 PM   #8
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Quote:
Originally Posted by Miles Prower View Post
If you have just the one stage, then there's just one choice: Anode Follower.
I'm having trouble picturing how this will work -- am I just taking one side of the secondary and connecting it to the grid through a resistor? Or just take right from the plate ... presumably through a cap?

Quote:
Originally Posted by revintage View Post
What tube?
12HG7 to start with. With a 5K:32 OPT for headphone use.
  Reply With Quote
Old 4th October 2009, 08:52 PM   #9
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
Quote:
Originally Posted by ddd View Post
You can ground the cathode resistor through the second coil or part of it. Add a cathode capacitor to increase the gain of the stage as well.
Mind the direction of the coil.
I think that I have seen that done, but I can not remember where.

If you have not purchased the transformer yet then you could specify one specifically for cathode winding feedback. Tim de Paravicini did that in his EAR HP4 headphone amp.
  Reply With Quote
Old 4th October 2009, 08:56 PM   #10
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Quote:
Originally Posted by Gordy View Post
If you have not purchased the transformer yet then you could specify one specifically for cathode winding feedback.
Unfortunately, I'm on a DIY diet, so the only option is to reuse what I have. The EAR seems to have its own little winding for this.

Last edited by dsavitsk; 4th October 2009 at 08:59 PM.
  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
Screen Driven Dissimilar Pentode SE Anti-Triode Spud kenpeter Tubes / Valves 2 26th July 2008 02:22 AM
Pentode spud...? Fuling Tubes / Valves 3 29th January 2005 07:26 AM
' single ended xconductance 0 feedback ' amp hitsware Solid State 1 12th October 2004 09:36 AM
Parallel, single-ended Pentode. How? arnoldc Tubes / Valves 2 16th December 2003 10:35 PM


New To Site? Need Help?

All times are GMT. The time now is 06:54 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