tube pop/flash on powerup

[calbruc]

Hey guys,

I just finished building my Crack three days ago. To my astonishment, it passed the resistance and voltage checks and has been working like a champ. Put quite a few hours on it in the past few days.

Today when I turned it on, the 6080 tube popped with a visible flash. I shut it off and tried it a little later, tubes warmed up and it seems to be working fine.

I searched the forum and only found a couple results about this. One said that it could have been some gas in the tube burning off and not likely a big deal, another seemed to think circuit checks were in order.

I was just wondering if anybody had any ideas about this or things I should look for when troubleshooting.

Thanks!

 

[Laudanum]

Could be as simple as the tube going south.  I had a 5998 tube do as you describe 3 or 4 times before taking a dirt nap.  It may not be the tube but it's a good idea to have a spare or two on hand.  Having a spare to swap in would easily rule the tube in or out as being the culprit.  The 6080's and 6AS7's are still inexpensive. 

 

[Paul Birkeland]

Run the tube in overnight to let it cook a bit, it's likely just some residual gas that needs to be absorbed by the getter.

 

[calbruc]

Thanks for the replies.

I'll keep it running over night.

Glad to know it's probably not anything serious!