Tubes Asylum

Questions about tubes and gear that glows. FAQ

Return to Tubes Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Do I have a problem here?

50.36.116.74
Posted on October 12, 2020 at 03:09:41
Todd R
Audiophile

Posts: 616
Location: Michigan
Joined: October 10, 1999
 One of my EL84 tubes has a hard bright glow on start up, which calms down as it warms up. It sounds ok so far.

 

Hide full thread outline!
    ...
RE: Do I have a problem here?, posted on October 12, 2020 at 13:09:31
immatthewj
 Is that EL84 being utilized as an output tube?
I've seen that with other output tubes I've had.
If the bias is okay, I'd run with it until it pops.

 

RE: Do I have a problem here?, posted on October 12, 2020 at 13:19:26
Sondek
Audiophile

Posts: 9632
Location: Fort Worth
Joined: May 17, 2000
Contributor
  Since: April 5, 2002
 Generally speaking, no you don't.

I think what you're describing is often called "tube flash".

If you'll enter those words into the search box, you'll get loads of posts about it.

 

RE: Do I have a problem here?, posted on October 12, 2020 at 18:26:03
Jonesy
Audiophile

Posts: 3156
Location: Winnipeg, Manitoba
Joined: September 1, 2005
Contributor
  Since: March 1, 2018
 A tube can sometimes take longer to settle in if the contacts are dirty or loose.

Wouldn't hurt to clean the pins and socket contacts. Also tighten the contacts to make sure the tube is snuggly seated.

You could also try swapping positions with another tube to determine if it's the tube or socket.

Cheers!

Jonesy


"I know just enough to get into trouble. But not enough to get out of it."




 

RE: Do I have a problem here?, posted on October 13, 2020 at 02:45:03
Todd R
Audiophile

Posts: 616
Location: Michigan
Joined: October 10, 1999
 I have changed tube positions, it's the tube.
I have a short movie of it, but doesn't look or i can post it here.

 

RE: Do I have a problem here?, posted on October 13, 2020 at 05:38:55
Jonesy
Audiophile

Posts: 3156
Location: Winnipeg, Manitoba
Joined: September 1, 2005
Contributor
  Since: March 1, 2018
 Ah, OK.

If you haven't already cleaned the tube pins, give that a try.

Otherwise the behavior isn't such that you should be overly concerned about if everything else is working fine. (In concurrence with the other posts.)

Cheers!

Jonesy


"I know just enough to get into trouble. But not enough to get out of it."




 

RE: Do I have a problem here?, posted on November 4, 2020 at 11:27:53
BillWojo
Audiophile

Posts: 186
Location: NJ
Joined: July 7, 2017
 You need to tell us if it's the plates getting red or the filament "flashing". If it's the plates, the long grey/black structure in the tube, it's red-plating. This can cause destructive damage to the amp. The tube is drawing way to much current when its red-plating. Never run an amp in this condition.

BillWojo

 

Page processed in 0.021 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]