Power tubes not drawing current - 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 14th February 2011, 11:54 PM   #1
diyAudio Member
 
Join Date: Nov 2010
Default Power tubes not drawing current

I'm building an Eiclone monoblock stereo. It's an El34 ultralinear amp. Strangest thing. The tubes are not drawing any current. I've got like 570 vdc on the plates and -75 on the grids. It's not bad tubes....I've substituted two pairs and the same results. The tubes are drawing like 1 ma of current. The plates should be about 90 volts less. I'm baffled!

Thanks!
David
  Reply With Quote
Old 15th February 2011, 12:10 AM   #2
diyAudio Member
 
Join Date: Feb 2008
Location: Niederösterreich
With the grids at -75v your tubes are in cutoff and cannot possibly pass much current at all. As you decrease the grids to closer to ~ -30v the tubes will start to conduct and your plate voltage will decrease due to the current draw. This amp is fixed bias?
  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
Peavey 2000 Drawing huge amounts of current. andrew58 Solid State 6 20th October 2007 05:00 PM
drawing a loadline for a power stage EL34 tube. audio_moksha Tubes / Valves 3 29th January 2007 07:30 PM
Drawing Schematics for Tubes Geek Tubes / Valves 10 4th February 2006 07:42 AM
Drawing power from USB or Firewire Noisetonepause Everything Else 7 17th May 2003 05:03 PM
Opinions: best current production tubes SHiFTY Tubes / Valves 4 9th August 2002 03:36 PM


New To Site? Need Help?

All times are GMT. The time now is 10:43 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