How can you tell if your tubes are Cathode Poisoned?

[INX]

I left my amp on standby for 12 hours, and it has 550V across two JJ 6L6GC's.

Thanks~!

[rockon1]

Still sound ok? If so I wouldnt worry about it. Bob

[INX]

Sounds a bit different. We'll see. Gotta crank that thang now that I got P-Rails.

[Trout]

I left my amp on standby for 12 hours, and it has 550V across two JJ 6L6GC's.

Thanks~!

Isn't the B+ lifted during standby?

Back in the day of Tube TV's, when they first went to " Instant On" sets,
tube filaments were left running 24/7/365.
My dad (Magnavox Regional Tech) once told me that he felt it improved the overall reliability due to the lack of repeated cold cycling.

[Blue Strat]

I left my amp on standby for 12 hours, and it has 550V across two JJ 6L6GC's.

Thanks~!

Step away from the computer....and stop reading nonsence about cathode poisoning.

How do they sound?

[TweeDLX]

Step away from the computer....and stop reading nonsence about cathode poisoning.

How do they sound?
+1! I once forgot and left my 5E3 on after a gig. Came back the next night to find a very warm amp and thought, "Oh crap...there go the tubes". Not so. They worked fine.

Mike

[evacuated]

Isn't the B+ lifted during standby?

Back in the day of Tube TV's, when they first went to " Instant On" sets,
tube filaments were left running 24/7/365.
My dad (Magnavox Regional Tech) once told me that he felt it improved the overall reliability due to the lack of repeated cold cycling.


That does make sense. I cringe every time those old Mullards flash on power up. :worried I know it's the way they were made, but I still can't help thinking that they're gonna let go.

[donnyjaguar]

I've left amplifiers on in standby for a week. I was concerned, but after checking the bias and finding it exactly where it should be I was able to sleep at night. :)

[INX]

They sound OK. That amp sounds best when the Mullards and JJ's have been on over an hour. I like to let it warm up that much and it just GUSHES beautiful grail tone.

[mark norwine]

I left an ampeg GS-12R on ("on" meaning "running"...it doesn't have a standby switch) for 2 weeks while I was away on vacation.

No harm at all. The studio was warm, though.....