Ideas on weak left channel with static? - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Tubelab
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubelab Discussion and support of Tubelab products, prototypes and experiments

Thread Tools Search this Thread
Old 13th June 2010, 05:16 PM   #1
diyAudio Member
Join Date: Aug 2009
Location: Missouri
Default Ideas on weak left channel with static?

Got my completed TubelabSE checked out and into my audio room. Listened to some music and noticed my left channel outputting less than the right, and there is a little static creeping in there as well. Both channels have a slight buzz, owed to the Hammond 270HX transformer I suspect. I switched my output tubes and the static/weakness stayed with the left channel, so ruled out output tubes. I checked my voltage at the speaker posts while playing a 315Hz test tone, and got .28 volts on the problem left channel and about .48 on the right channel. Any ideas on what might cause this? Thanks,
  Reply With Quote
Old 13th June 2010, 06:19 PM   #2
Join Date: Jan 2008
Blog Entries: 2
You are attacking this problem in the right way. Presuming that the right channel is operating correctly, work through from input to output checking DC conditions without any test tone, and looking for a point where the left channel diverges from the right...

If you have a 'scope you can look at your injected test tone, which will also help you localize the fault.

Exercise extreme care while fault-finding any tube amp, keeping one hand in your pocket is often recommended as a safety measure.

  Reply With Quote
Old 13th June 2010, 06:21 PM   #3
rknize is offline rknize  United States
diyAudio Member
rknize's Avatar
Join Date: Feb 2009
Location: Chicagoland
Send a message via AIM to rknize Send a message via Yahoo to rknize
Try swapping the input tubes? Also measure the voltage at the plates and across the cathode resistors of the input tubes.
  Reply With Quote
Old 13th June 2010, 06:24 PM   #4
diyAudio Member
Join Date: Mar 2010
If that unit (I'm not familiar with it) has input switches, such as tape monitor, clean those. Very common cause of such problems.
  Reply With Quote
Old 13th June 2010, 07:28 PM   #5
diyAudio Member
Join Date: Aug 2009
Location: Missouri
Thanks you guys!
Switched input tubes, and the problems followed the input tube, so switching them made my right channel affected. This is a bad input tube then! Thanks so much for the help. Now, to find a 5842 that isn't $60, that'll be the next chore.

Have a great rest of your Sunday,
  Reply With Quote


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
Harmon Kardon 930 receiver weak left channel richmondscribe Solid State 12 19th March 2017 05:25 PM
Carver M4.0t with weak channel sjdemark Solid State 15 9th February 2015 03:40 PM
Parasound 1200 II left channel static and.... AJ Bertelson Solid State 34 11th February 2013 12:28 PM
NAD 3240PE VERY weak right channel danter Solid State 1 14th January 2008 02:43 PM

New To Site? Need Help?

All times are GMT. The time now is 03:35 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2