NOS tube wakeup from long sleep?

[GearHeadFred]

I recently have inherited a large batch of tubes. In the batch are some gems.. Mullard ECC83s from 1958, RCA from the early 60's, etc.

I plugged one into V1 of my JTM last night and almost had a heart attack as it lit up like a Christmas tree (long white glow). These tubes have been sitting for 50+ years. It did eventually work OK.

I imagine that over the decades, air molecules manage to sneak in, even in the best of construction.... Perhaps there is a better way to wake them up???

Is there any process or procedure you have used to awaken sleeping beauties?

[scottl]

Tubes like Mullards flash on cold start. Quick warm up of the filaments, purposely designed in from what I have heard.

The flash is normal.

[GearHeadFred]

Thanks for the reply Scott.

I'm familiar with the CV power-up flash.. This was different.. Much brighter and longer.. and it did not occur on subsequent power ups (as the CV flash does).

[tony_clifton]

I imagine that over the decades, air molecules manage to sneak in, even in the best of construction.... Perhaps there is a better way to wake them up???


Hate to be a wiseass but if that would be true, the tube would burn up as soon as you turn on the amp.

The silver in the top is a chemical that reacts with oxygen (to vacuum it) so as long as that is present, the tube is vacuum.

Try dropping one!

[smolder]

Try dropping one!

noooooooooooooooooo! ; )

[Ronsonic]

Back in the day, the US used 110-115 mains voltages, that made it possible to build an amp without a power transformer. For the heaters they were using tubes that added up to the line voltage - 35 and 50 volt heaters were common for rectifiers and power tubes. To make this work the tubes had to all have the same warmup time, IIRC 12 seconds was about standard. Rather than have bunches of safe and unsafe tubes out there and counting on people to know to look for the letter "A" after the tube number, mostly all tubes evolved to having controlled warmup.

Europe with its higher line voltage never had the option of building transformerless sets so there were few controlled warmup tubes ever made. Since there's no standard, well there's no standard, some burn long and bright on power up, others less so.

[GearHeadFred]

Hate to be a wiseass but if that would be true, the tube would burn up as soon as you turn on the amp.

The silver in the top is a chemical that reacts with oxygen (to vacuum it) so as long as that is present, the tube is vacuum.

Try dropping one!

I'm familiar with the purpose and function of the getter.

I appreciate the opinions, but I'm hoping one of the guys who deal with large volumes of NOS tubes will respond. I recall reading about a "slow power up" of the filaments on stored NOS tubes somewhere (but cannot locate that now)

[Timbre Wolf]

The flash is normal.
:agree

And to add to that, you won't get a repeat start-up flash performance from that tube until it has cooled completely.

- T

[GearHeadFred]

OK, you guys were right.. The bright flash does reoccur when completely cold.

I also got my hands on a Hickok tester so I can measure the mutual conductance.
The '58 Mullard is alive and tests well.

Was I dreaming about the slow application of filament voltage on stored tubes?

EDIT: I'm not loosing my mind! Here is the link: http://www.nd2x.net/tube-prep.html

Discuss!

[Timbre Wolf]

Discuss!

Completely unnecessary.

In my experience with vintage audio tubes, you start 'em up just like brand new production tubes (I make sure to test first - especially with power and rectifier tubes). If you've had a vacuum failure, the getter will be spent, and you'd be able to see this in a visual inspection. If you have not had a getter failure, there is not much change happening inside the evacuated tube. Most "aging" as we know it is due to oxidation, which won't happen in an evacuated tube.

- Thom

[tejastubes]

OK, you guys were right.. The bright flash does reoccur when completely cold.

I also got my hands on a Hickok tester so I can measure the mutual conductance.
The '58 Mullard is alive and tests well.

Was I dreaming about the slow application of filament voltage on stored tubes?

EDIT: I'm not loosing my mind! Here is the link: http://www.nd2x.net/tube-prep.html

Discuss!

I think there is some validity to the article but I would not worry about this whatsoever. Actually on properly calibrated functioning test equipment, in rare cases (most often not) tubes which have sat will show positive for gas but as they are heated up/put under load the positive reading for gas will usually disappear in a matter of seconds or minutes, as the case may be, and then the tube does not test positive for gas any longer. But this is not correlated with an initializing type of flash as you have noticed with the British made tube which is completely normal. EI 12ax7 do this is as well. It is a function of how the tube was constructed.

[Ronsonic]

We only have about 70 years history with tubes of (relatively) modern construction, and what we know from them is that they haven't aged on the shelf. Older tubes from the 20s and early 30s were relatively primitive and some have started to admit air by now. But the types that interest us in the guitar world aren't old enough to have issues yet.