Blue Tube Red Plating = Help! - Page 3 - 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 16th January 2011, 05:31 PM   #21
diyAudio Member
 
sepolansky's Avatar
 
Join Date: Nov 2007
Location: Maryland
6922 is a twin triode similar to a 6DJ8
  Reply With Quote
Old 16th January 2011, 05:40 PM   #22
diyAudio Member
 
richwalters's Avatar
 
Join Date: Sep 2003
Location: Alps:Tube amp designs over 150W, SMPS guru.
Quite right.....Apologies my error. I was thinking of another.
  Reply With Quote
Old 18th January 2011, 05:50 AM   #23
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
Just as a thorough follow-up, there was bad news and good news: bad news was that the problem re-occurred after I put the original coupling caps back in (yes, with insulated leads). I checked all components again, but this time I took a peek on the other side of the board (hard to do since the top is not easily removed). I saw that solder from the coupling caps melted below into wiring from OPTs and the two were in contact. I've insulated the wire and everything is back to normal. Unfortunately I can't move the wire the way it's designed, so this was an accident waiting to happen.
  Reply With Quote
Old 18th January 2011, 10:55 AM   #24
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
After soldering always do a visual check before switching on. Always use the right amount of solder - too little gives a bad joint, too much can also give a bad joint and shorts to other things. As far as possible, don't carry solder to the joint on the iron as this wastes the flux so you try to compensate by adding more and more solder to recover the situation.
  Reply With Quote
Old 26th January 2011, 11:15 PM   #25
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
Okay, it seems that I must have damaged something with the red plating: After warm up one channel is consistently a little louder than the other, and when I power on the amp the weaker channel (R) makes little popping sounds for a few seconds. I also notice the output tube socket that redplated sometimes will not allow me to increase the bias pass a certain point. The other sockets bias fine. Otherwise the amp is performing well. Does this sound like a bad cathode resistor? or cap?

The schematic on page 1 for the bias circuit seems fairly accurate with the exception that there's now one per output tube.

Last edited by wushuliu; 26th January 2011 at 11:24 PM.
  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
Blue glow in tube. Is the tube dead or not? Pentium100 Tubes / Valves 37 22nd October 2009 06:45 PM
Tube glows red hot, blows fuse damagefactor Tubes / Valves 17 24th February 2008 07:42 PM
fisher sa-16 very red tube and? robertleo Tubes / Valves 2 18th June 2007 09:38 PM
WTT: Blue LEDs for Red & Red/Green LEDs CaliforniaBob Swap Meet 2 9th June 2003 02:58 PM
Blue glowing tube Gabster Tubes / Valves 24 27th September 2002 04:08 AM


New To Site? Need Help?

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