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 31st August 2010, 05:40 PM   #1
diyAudio Member
 
Mosquito's Avatar
 
Join Date: Sep 2009
Location: Santa Fe, Argentina
Default 6v6 SEP

Hi everyone!
Well, It seems that I'm approaching the final stadium of the "tube sickness", I'm entering the SE madness...
Once on it, I remember the words of a DIY guy wiser than me: "I never heard an EL84 amp that do not sound at least very good" but also remembered another wise guy saying " God knows that the world do not need another EL84 amp"
So, I was looking around for some simple solution, and from one discussion in this forum, my sight falls over this one:
picture A

Well, I was trying to re- arrange the schematic for my better understanding:
picture B

And there is the arrangement of G3 - R10 (100K) that confuses me, because is very different to others pentode-pentode SE amps (the Mullard 3_3, for example)
It is a kind of local feedback or simply a mistake of my re- arranged drawing?
By the way, I decided for a 6V6G - 6J7G because I want the amp to be full octal tubes (there will be a 5U4G too), 4-5 watt will be enough, and these tubes looks really cool .
I'll be grateful for any advice
Attached Images
File Type: png 6v6se.png (64.0 KB, 811 views)
File Type: jpg SEP-6V6.jpg (70.8 KB, 799 views)
__________________
If I only had a dollar for every song I've sung...

Last edited by Mosquito; 31st August 2010 at 05:47 PM.
  Reply With Quote
Old 31st August 2010, 05:46 PM   #2
TheGimp is offline TheGimp  United States
diyAudio Member
 
TheGimp's Avatar
 
Join Date: Aug 2009
Location: Johnson City, TN
I think the 100K resistor is providing Schade Feedback. There are several threads here on it. Search for Schade.

Also search the web for O.H.Schade Beam Power Tubes 1938..

A little over half way down here:

Tube Data
  Reply With Quote
Old 31st August 2010, 06:24 PM   #3
diyAudio Member
 
Mosquito's Avatar
 
Join Date: Sep 2009
Location: Santa Fe, Argentina
Thanks, I suspect something like this, but I wasn't sure,... In the doubt I supress the GNF of the original
Nevertheless, I believed that the Shade local FB being plate to plate
__________________
If I only had a dollar for every song I've sung...
  Reply With Quote
Old 31st August 2010, 08:02 PM   #4
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
Quote:
Originally Posted by Mosquito View Post
Thanks, I suspect something like this, but I wasn't sure,... In the doubt I supress the GNF of the original
Nevertheless, I believed that the Shade local FB being plate to plate
Yes it is - that's just regular feedback, but not much of it .
  Reply With Quote
Old 31st August 2010, 08:06 PM   #5
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Try as is, with both feedbacks. It should sound nice.
__________________
"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 31st August 2010, 08:23 PM   #6
diyAudio Member
 
Mosquito's Avatar
 
Join Date: Sep 2009
Location: Santa Fe, Argentina
Yes, it's a wise policy, mods, maybe, but not before trying the original...
__________________
If I only had a dollar for every song I've sung...
  Reply With Quote
Old 31st August 2010, 11:07 PM   #7
diyAudio Member
 
Nikolas Ojala's Avatar
 
Join Date: Aug 2004
Location: Finland
That two pentode circuit reminds me of another two pentode amplifier.

Mullard 3-3 Three Watt Amplifier

There is a bonus: DC-connected stages. No need for a capacitor between them.
__________________
High-order harmonics are more offensive than low.
  Reply With Quote
Old 31st August 2010, 11:31 PM   #8
diyAudio Member
 
Mosquito's Avatar
 
Join Date: Sep 2009
Location: Santa Fe, Argentina
Yes, it's a classic, but I'd like to try the other one just because it is "different"
__________________
If I only had a dollar for every song I've sung...
  Reply With Quote
Old 6th November 2010, 01:40 PM   #9
gja is offline gja  Spain
diyAudio Member
 
Join Date: Nov 2005
Did you finish the amp?
How does it sound?Agree with you that the tubes look awesome.
  Reply With Quote
Old 6th November 2010, 02:22 PM   #10
diyAudio Member
 
Mosquito's Avatar
 
Join Date: Sep 2009
Location: Santa Fe, Argentina
Unfortunately not. Some personal and financial issues leads me to stop the project . Hope to restart very soon.
Kevin Connor builded up a similar thing, with great success, and shared a lot of useful info, specialy about the pentode gain stage.
Mine will be different in some aspects.
Last thing I did on this, was a provisory schematic to look at possible ways to inject the partial feedback signal. Nothing other than that. It still remains the tubes to be ordered and to think about the chassis, etc
Here the circuit, but need still a lot of work...
I'll let now here , if any progress
Cheers
J
Attached Images
File Type: gif Pentode+Pentode SE 5W.gif (23.6 KB, 613 views)
__________________
If I only had a dollar for every song I've sung...
  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
EL84 SEP schematic. Some questions. Cassiel Tubes / Valves 8 6th January 2013 07:42 PM
replace attenuator on Golden Tube SEP-1SE wintermute222 Parts 2 3rd October 2011 07:37 PM
WTB: Sanyo Oscon SEP 330uF/10V reaction Swap Meet 0 1st August 2007 08:32 PM
Pentode CCS for parafeed SEP?? aletheian Tubes / Valves 7 22nd December 2005 09:59 PM
FS: Sanyo OSCON SP SEP SEPC Series Caps Orb Swap Meet 1 23rd September 2005 01:54 PM


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