Bias current - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 March 2002, 07:57 PM   #1
diyAudio Member
 
Join Date: Jun 2001
Default Bias current

I just turned on my leach amp to set the bias current but turning the potentiometer didn't do anything. The current was stuck at around 20 ma. Can anybody tell me what's going on?

Thanks.

Peter
  Reply With Quote
Old 12th January 2004, 06:43 PM   #2
diyAudio Member
 
Join Date: Jan 2004
Location: Cortez Colo.
Default leach bias current

Hello It seems that I may have a problem with adjusting the bias current. The bias current stays around 19 to 25 ma. Please help.
Serosmaness
  Reply With Quote
Old 12th January 2004, 08:48 PM   #3
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Most problems with bias current adjustment are caused by the potentiometer........ Carefully try to meassure the output of the potentiometer and check that it actually variates the voltage to the base of the Bias transistor
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 12th January 2004, 09:01 PM   #4
diyAudio Member
 
Join Date: Jan 2004
Location: Cortez Colo.
Thanks Jan for the reply.I changed the pot and checked on the board for change of resistance. Everything checked good.
I put a squarewave on the input and got a amplified output but it was not clean.
The good channel is biased to 115 ma and works but its response is notably different than my Sumo. Less bass.
Thanks Serosmaness
  Reply With Quote
Old 13th January 2004, 03:22 PM   #5
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Did you check for a defect bias transistor ???
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 13th January 2004, 03:45 PM   #6
diyAudio Member
 
Join Date: Jan 2004
Location: Cortez Colo.
Thanks again Jan for your response. I found the problem. I swapped the B and E on the output transistors. I biases fine now.
Thanks again
Serosmaness
  Reply With Quote
Old 13th January 2004, 04:39 PM   #7
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Ok Then happy Amp'ing....
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  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
bias voltage vs bias current woodturner-fran Tubes / Valves 3 24th February 2007 11:24 PM
LTP bias current cunningham Solid State 2 12th January 2005 08:39 PM
bias current: Zen vs. Aleph Peter Huang Pass Labs 6 4th August 2003 05:39 AM
Leach Amp bias current (what is yours set to?) BrianGT Solid State 3 21st February 2002 08:53 AM
BOZ Bias Current gema Pass Labs 2 20th February 2002 07:28 PM


New To Site? Need Help?

All times are GMT. The time now is 07:33 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