Techies Help with 6080 problem

[John EH]

I was tube rolling this morning and dropped in an old Amperex 12AU7 Bugle Boy and didn't like it so I dropped in it's brother. 

It gassed up and flashed pretty bright and then I noticed I lost a channel.  Pulled the headphone jack halfway out and got both channels.

Turned CrackPipe upside down and saw the left channel C4S board LED's not lit.

Put it on the bench, powered up and both C4S side lights came on then the left channel dropped off.  So I figure it has to do with the 6080 warming up.  I swap the 6080 and voila' everything is working famously (with a working 12AU7).

So the amp is okay but here comes the goofy part.  I have a TV-7 tube tester and I take the 6080 and both Triodes test perfectly.

Any ideas? 

John

[2wo]

What do mean by "Gassed up and flashed"?  ?
Many European filaments will flash when started, it's normal.

Odds are it's the mechanical stress of tube rolling, a weak pin connection or something like that...John

[John EH]

Yeah I've seen many a tube gas up and flash on start up but this lit up like a Chinese Christmas Tree.

I figured it out.  I found a short on Triode 1.  I previously only tested the triodes and didn't do the short test.  Reading the tester manual helped. Imagine that.

John

[John EH]

More to the story.  I tested the offending 12au7 and it's fine.  I have 4 - 6080's and I had just rolled a new one in not 5 minutes before.  Maybe it just gave up the ghost after a minute or two of use.  Especially with me turning off and yanking tubes fast.

Amps fine.  That's all that matters.  Trying to find a 5998 to roll in however I think the ebayer's have lost their minds on price on that tube.

John