#26 pre amp - Page 274 - 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 21st March 2013, 01:46 PM   #2731
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
0V accros 100R grid stopper
  Reply With Quote
Old 21st March 2013, 01:49 PM   #2732
stajo is online now stajo  Sweden
diyAudio Member
 
Join Date: Jun 2011
Location: Stockholm
Check also that you really have plus on Rodsthingie on cathode side and minus on ground side on the 10R resistor
  Reply With Quote
Old 21st March 2013, 01:49 PM   #2733
massimo is offline massimo  Italy
diyAudio Member
 
Join Date: Dec 2002
Location: Milan, Italy
Thus better, isn't it?
Question: was the pot set to -infinite (fully counterclockwise / central tap to gnd) during the previuous tests? or were the RCA shortcircuited?
  Reply With Quote
Old 21st March 2013, 01:52 PM   #2734
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by stajo View Post
Check also that you really have plus on Rodsthingie on cathode side and minus on ground side on the 10R resistor
9,5V across 10R, +1,524V filaments
  Reply With Quote
Old 21st March 2013, 01:54 PM   #2735
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by massimo View Post
Thus better, isn't it?
Question: was the pot set to -infinite (fully counterclockwise / central tap to gnd) during the previuous tests? or were the RCA shortcircuited?
The pot is shorted = minimum volume possible.
  Reply With Quote
Old 21st March 2013, 01:54 PM   #2736
stajo is online now stajo  Sweden
diyAudio Member
 
Join Date: Jun 2011
Location: Stockholm
Did you check what I said? Cathode is positive to ground?
  Reply With Quote
Old 21st March 2013, 01:57 PM   #2737
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by stajo View Post
Did you check what I said? Cathode is positive to ground?
Cathode is the tube pin where is connected the 10R? DVM plus lead to cathode where is connecte 10R & DVM minus lead to gnd reads +9,59V
  Reply With Quote
Old 21st March 2013, 02:05 PM   #2738
stajo is online now stajo  Sweden
diyAudio Member
 
Join Date: Jun 2011
Location: Stockholm
Same voltages if you switch tube or run both?
  Reply With Quote
Old 21st March 2013, 02:06 PM   #2739
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
I only have connected one tube, do you want that I connect the two tubes?
  Reply With Quote
Old 21st March 2013, 02:08 PM   #2740
massimo is offline massimo  Italy
diyAudio Member
 
Join Date: Dec 2002
Location: Milan, Italy
Looks good. 136V on plate, 9.59V on cathode is basically the same working point as per Andy's schem (138 and 10).
Add a second grid stopper (resistor body as close to the socket pin as possible) ad fire it up!
If online newspaper won't report as breaking news a big mushroom cloud over Catalonia in the next ten minutes, means that you can check your preamp with the oscope
  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



New To Site? Need Help?

All times are GMT. The time now is 04:56 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