Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which i assumed were
used). I know weird stuff like cat. pollution, g1 pollution, etc, but this
was a *drastic* change*... When first fired up & biased, the toobs were
pulling less current than expected, and the whole amp, forget the freq.
response, sounded ... like a candidate for a good parts donor. But... left
it on for a day, since I wanted to play with my shop amp. After a day, It
was a different amp - had to be re-biased, and needed about 1/3 voltage to
drive the output stage. I've never experienced this much of a change - i
burn-in new tubes, but [?]OS? and if this goes for power toobs, i guess
preamp toobs will follow suit to some degree? what do dealers do with NOS
tubes when they test them? Is there a burn-in time for NOS tubes?
-dim

Gas maybe. Hot getters consumed it.

As for what dealers do, check
http://www.watfordvalves.com/mainindex.htm, for example.

cheers, Ian


"Shiva" wrote in message
...
Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which i
assumed were
used). I know weird stuff like cat. pollution, g1 pollution, etc,
but this
was a *drastic* change*... When first fired up & biased, the
toobs were
pulling less current than expected, and the whole amp, forget the
freq.
response, sounded ... like a candidate for a good parts donor.
But... left
it on for a day, since I wanted to play with my shop amp. After a
day, It
was a different amp - had to be re-biased, and needed about 1/3
voltage to
drive the output stage. I've never experienced this much of a
change - i
burn-in new tubes, but [?]OS? and if this goes for power toobs, i
guess
preamp toobs will follow suit to some degree? what do dealers do
with NOS
tubes when they test them? Is there a burn-in time for NOS
tubes?
-dim

"Fred Nachbaur" wrote in message
. ..


Patrick Turner wrote:

Ian Iveson wrote:


Gas maybe. Hot getters consumed it.

As for what dealers do, check
http://www.watfordvalves.com/mainindex.htm, for example.

cheers, Ian


Possibly Ian is right, but I have never seen this phenomenon.
It certainly isn't common.

Watford Valves sell EH6550 for 22 british pounds, which is rip off
territory;
they are far cheaper at New Sensor.
I guess they can easily afford the free matching and testing.

Patrick Turner.

I also agree with Ian's assessment, and have seen this happen with NOS
tubes that were in storage for many decades (most recently with a pair
of 832A's). Somewhere I read an explanation about this, and it was
indeed due to residual or "outgassed" gasses that the getter absorbs
during normal operation. Let's see... ah, here's something:

http://www.nd2x.net/tube-prep.html

The link to the Swedish site (SM5BSZ) didn't work for me, and the one to
Svetlana talkes about big transmitting tubes, so isn't really too
appropriate.

Hm... the mechanism seems to be more the fact that gas molecules move
around more when heated, than the higher reactivity of the getter
itself. But who really knows for sure, all I know is that it definitely
*does* happen.

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+


Hi Ian, Patrick, Fred -
I'm glad Fred has seen this - I'm glad *Fred* has seen this - it really
makes little sense to me. Outgassing? It would seem that I'd be able to
see fluorescence from ionization ( i still have a yugo 12ax7 which glows
green...), and there really was nothing special... This is verging on that
mystical ****...

Shiva wrote:

[...]


Hi Ian, Patrick, Fred -
I'm glad Fred has seen this - I'm glad *Fred* has seen this - it really
makes little sense to me. Outgassing? It would seem that I'd be able to
see fluorescence from ionization ( i still have a yugo 12ax7 which glows
green...), and there really was nothing special... This is verging on that
mystical ****...

Well, maybe you could see light emission due to ionization (not quite
the same as fluorescence) but that's usually bluish-white. Usually by
the time that happens the tube is pretty close to being toasty-ohs. The
green-glowing Yugo 12AX7 probably *is* due to fluorescence, on the mica
maybe.

Another possible mechanism for the observed burn-in phenomenon is "space
junk" being boiled off the surface of the cathode.

It can be fun to ponder such things, but beyond a certain point we just
shrug our shoulders and enjoy the ride as we sail into the mystic. [That
thought struck while listening -not to Van Morrison- but to Toto's
"Hydra", often pooh-poohed by the hip as just a precursor of the 80's
hair bands... but I don't care, I like it.]

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+

Shiva wrote:
Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which i assumed were
used). I know weird stuff like cat. pollution, g1 pollution, etc, but this
was a *drastic* change*... When first fired up & biased, the toobs were
pulling less current than expected, and the whole amp, forget the freq.
response, sounded ... like a candidate for a good parts donor. But... left
it on for a day, since I wanted to play with my shop amp. After a day, It
was a different amp - had to be re-biased, and needed about 1/3 voltage to
drive the output stage. [...]

As an afterthought... I'm wondering if Lord Valve, Ned Carlson and Jim
McShane have encountered this phenomenon. You'd think they'd have seen a
*lot* of NOS tubes over the years.

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+

"Shiva" wrote in message
...
Hi Ian, Patrick, Fred -
I'm glad Fred has seen this - I'm glad *Fred* has seen this - it really
makes little sense to me. Outgassing? It would seem that I'd be able to
see fluorescence from ionization ( i still have a yugo 12ax7 which glows
green...), and there really was nothing special... This is verging on
that
mystical ****...

Heh, on my Eico 625 tube tester, I can set up most any 12AT7 so that
a beam comes out from the plate and makes a blue spot on the glass,
well one tube I had actually showed a purple glow leading from the
hole in the plate to the spot on the glass. Now *that* was most
definetly a gassy tube!

Tim

P.S. Anyone wondering, the combo is 1 up, 8 & 9 down (the rest centered),
SEL=4, FIL=5 or 6.3V. The triodes can be switched, that is, 3 down, 6 up
(instead of 1 and 8).

--
In the immortal words of Ned Flanders: "No foot longs!"
Website @ http://webpages.charter.net/dawill/tmoranwms

Fred Nachbaur wrote:

Shiva wrote:
Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which i assumed were
used). I know weird stuff like cat. pollution, g1 pollution, etc, but this
was a *drastic* change*... When first fired up & biased, the toobs were
pulling less current than expected, and the whole amp, forget the freq.
response, sounded ... like a candidate for a good parts donor. But... left
it on for a day, since I wanted to play with my shop amp. After a day, It
was a different amp - had to be re-biased, and needed about 1/3 voltage to
drive the output stage. [...]

As an afterthought... I'm wondering if Lord Valve, Ned Carlson and Jim
McShane have encountered this phenomenon. You'd think they'd have seen a
*lot* of NOS tubes over the years.

Cheers,
Fred
--

I burn *everything* in, current or NOS. I have to. The new ones need to
have the cathodes cooked for awhile before they start emitting as
much as they are capable of. Best way for this is to crank the plate
voltage down and pull lots of current through 'em. About 60 mA at
350V is good for 6L6s. If you check emission before and after,
you'll see about a 10-20% increase. The NOS stuff gets the same
treatment, but I run those at full voltage (~450 to 470) and about 40
mA Ip. It's been a long time since I actually did any really extensive
before/after testing on NOS power tubes, since the dudes who buy
'em from me are more concerned with them not croaking on tour
than with any hifalutin' specs. I juice 'em up nice and hot and whack
the crap out of 'em with a nutdriver handle; if they don't spit fire, I ship
'em. ;-) BTW, if you saw the Allman Brothers on Jay Leno a few
days ago, you heard a set of mine. I also built the amp you heard
'em in. That tall amp Derek Trucks was playing through is the
one I'm talking about. (If you want the dope on it, run my e-mail
address on Google groups and use "Super Six" for keywords.)


Lord Valve
Tone Chaperone

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
QSC amps, RNC compressors, lots of other good stuff!

Partial Client List: * Derek Trucks/Allman Brothers Band *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* John Hall * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * The Right Half of AGA * Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at 303-778-1156

VISA - MASTERCARD - PAYPAL

Philo T. Farnsworth sez, "Vacuum tubes kick major ass.
Be a MAN...and buy some TODAY!"

Fred Nachbaur wrote:

http://www.nd2x.net/tube-prep.html

The link to the Swedish site (SM5BSZ) didn't work for me

http://antennspecialisten.se/~sm5bsz/recondit.htm

Haupaut tis van?

--
Oskari Heinonen * University of Helsinki * Department of Computer Science
* http://www.cs.Helsinki.FI/Oskari.Heinonen/

Lord Valve wrote:

Fred Nachbaur wrote:

Shiva wrote:
Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which i assumed were
used). I know weird stuff like cat. pollution, g1 pollution, etc, but this
was a *drastic* change*... When first fired up & biased, the toobs were
pulling less current than expected, and the whole amp, forget the freq.
response, sounded ... like a candidate for a good parts donor. But... left
it on for a day, since I wanted to play with my shop amp. After a day, It
was a different amp - had to be re-biased, and needed about 1/3 voltage to
drive the output stage. [...]

As an afterthought... I'm wondering if Lord Valve, Ned Carlson and Jim
McShane have encountered this phenomenon. You'd think they'd have seen a
*lot* of NOS tubes over the years.

Cheers,
Fred
--

I burn *everything* in, current or NOS. I have to. The new ones need to
have the cathodes cooked for awhile before they start emitting as
much as they are capable of. Best way for this is to crank the plate
voltage down and pull lots of current through 'em. About 60 mA at
350V is good for 6L6s. If you check emission before and after,
you'll see about a 10-20% increase. The NOS stuff gets the same
treatment, but I run those at full voltage (~450 to 470) and about 40
mA Ip. It's been a long time since I actually did any really extensive
before/after testing on NOS power tubes, since the dudes who buy
'em from me are more concerned with them not croaking on tour
than with any hifalutin' specs. I juice 'em up nice and hot and whack
the crap out of 'em with a nutdriver handle; if they don't spit fire, I ship
'em. ;-) BTW, if you saw the Allman Brothers on Jay Leno a few
days ago, you heard a set of mine. I also built the amp you heard
'em in. That tall amp Derek Trucks was playing through is the
one I'm talking about. (If you want the dope on it, run my e-mail
address on Google groups and use "Super Six" for keywords.)

I just tried looking up the RDH4 on what it says about
burning in tubes which have never been used, and I couldn't
see too much.

But I recall from someplace that the tube should be pre "cooked"
48 hours with the heaters left running, with the cathode tied to one side of the
6.3v,
and the all the other electrodes tied together, and to the other side of the 6.3v.
This makes the cathode "ready for service",
and after this is done the tube is said to last longer.
Then the tube can be left running with some applied voltage and current.

Anyone else aware of pre-cooking the tubes?

Many makers pre-used the tubes somehow, to avoid sending duds to
ppl; the military were not impressed by tubes which didn't work
when plugged in.

Patrick Turner.





Lord Valve
Tone Chaperone

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
QSC amps, RNC compressors, lots of other good stuff!

Partial Client List: * Derek Trucks/Allman Brothers Band *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* John Hall * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * The Right Half of AGA * Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at 303-778-1156

VISA - MASTERCARD - PAYPAL

Philo T. Farnsworth sez, "Vacuum tubes kick major ass.
Be a MAN...and buy some TODAY!"

Oskari Heinonen wrote:
Fred Nachbaur wrote:

http://www.nd2x.net/tube-prep.html

The link to the Swedish site (SM5BSZ) didn't work for me


http://antennspecialisten.se/~sm5bsz/recondit.htm

Haupaut tis van?

That works. Thanks!

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+

Hi RATs!

http://antennspecialisten.se/~sm5bsz/recondit.htm

Yes!

Taaksa Moikaa!

Happy Ears!
Al


Alan J. Marcy
Phoenix, AZ

PWC/mystic/Earhead

"Fred Nachbaur" wrote in message
. ..


Oskari Heinonen wrote:
Fred Nachbaur wrote:

http://www.nd2x.net/tube-prep.html

The link to the Swedish site (SM5BSZ) didn't work for me


http://antennspecialisten.se/~sm5bsz/recondit.htm

Haupaut tis van?

That works. Thanks!

Cheers,
Fred

Hi fred, a good common-sense site, though doesn't explainthe real grit. One
thing that's missed, when he talks about the getter action in poser tubes:
"In a big power tube the pumping may be arranged differently. I do not know
how, but as I understand it, the pumping does not work unless the tube is
heated."
Well, every tube needs to be heated for the getter to *try* to work.
Other than outgassing at temps, the stray gas molecules have to come in
contact with the getter flash - and the way to do that is by heating the
[gases?] & gettin' them suckers movin' fast, so they'll *slam* into the
flash, at which point a reaction is pretty certain. When I look inside of
some tubes, the flash is a bit white on the *inside* of the tube, which may
mean a less-than reactive surface, though I don't really know. I wonder if
anyone tried *heating the flash* in gassy tubes, which may act like the
getter being set off... Or just poluteall the mica. I once heated the
envelope of a microphonic el34 with a torch, the micas were all rattled
loose. The vacuum pulled the glass tighter over the micas 9got the idea from
looking at sheety Sovteck toobs), and the microphonics were controlled
(well, got better, at least), with no other effects. Then i got real sloppy
and cracked a microphonic 6550 (too much heat too soon & too local), but
maybe heating the flash... anyhow, when i have time... Maybe i could get a
military grant?
-dim

Shiva wrote:
"Fred Nachbaur" wrote in message
. ..


Oskari Heinonen wrote:

Fred Nachbaur wrote:


http://www.nd2x.net/tube-prep.html

The link to the Swedish site (SM5BSZ) didn't work for me


http://antennspecialisten.se/~sm5bsz/recondit.htm

Haupaut tis van?

That works. Thanks!

Cheers,
Fred


Hi fred, a good common-sense site, though doesn't explainthe real grit. One
thing that's missed, when he talks about the getter action in poser tubes:
"In a big power tube the pumping may be arranged differently. I do not know
how, but as I understand it, the pumping does not work unless the tube is
heated."
Well, every tube needs to be heated for the getter to *try* to work.
Other than outgassing at temps, the stray gas molecules have to come in
contact with the getter flash - and the way to do that is by heating the
[gases?] & gettin' them suckers movin' fast, so they'll *slam* into the
flash, at which point a reaction is pretty certain. When I look inside of
some tubes, the flash is a bit white on the *inside* of the tube, which may
mean a less-than reactive surface, though I don't really know. I wonder if
anyone tried *heating the flash* in gassy tubes, which may act like the
getter being set off... Or just poluteall the mica. I once heated the
envelope of a microphonic el34 with a torch, the micas were all rattled
loose. The vacuum pulled the glass tighter over the micas 9got the idea from
looking at sheety Sovteck toobs), and the microphonics were controlled
(well, got better, at least), with no other effects. Then i got real sloppy
and cracked a microphonic 6550 (too much heat too soon & too local), but
maybe heating the flash... anyhow, when i have time... Maybe i could get a
military grant?
-dim

I've heard of guys reflashing tubes in a microwave oven... but haven't
heard any stats on success ratio. ;-)

If you decide to try it, be sure to give it a dummy load (a cup of
water) so you don't fry your magnetron.

Got any "coasters" (bad CDs)? They make a nice light show in the
microwave. Wait till your significant other is out of the kitchen
though, if you leave it in a bit too long things get a little stinky.
Factory CDs work better than CDRs. (There's a great use for those AOL
demo CDs!)

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects, Vacuum Tubes & other stuff: |
| http://www.dogstar.dantimax.dk |
+--------------------------------------------+

Equally vague memories...various cathode materials are activated in
different ways. The most common has an additive that is evenly
distributed, but is only effective at the surface. It migrates at
some high temperature, and is also slowly consumed from the surface
in normal use at a rate that rises with temperature. Presumably if
you increase temperature without causing high-energy collisions
(high current low voltage) then you can get a surface coating to
build up because of migration without consumption. The additive
increases effectiveness by many times.

You can possibly rejuvenate the surface by repeating the activation
sequence.

cheers, Ian.

"Patrick Turner" wrote in message
...


Lord Valve wrote:

Fred Nachbaur wrote:

Shiva wrote:
Hi all -
I've built a stereo SEP using 6bg6 (old coke bottles, which
i assumed were
used). I know weird stuff like cat. pollution, g1
pollution, etc, but this
was a *drastic* change*... When first fired up & biased,
the toobs were
pulling less current than expected, and the whole amp,
forget the freq.
response, sounded ... like a candidate for a good parts
donor. But... left
it on for a day, since I wanted to play with my shop amp.
After a day, It
was a different amp - had to be re-biased, and needed about
1/3 voltage to
drive the output stage. [...]

As an afterthought... I'm wondering if Lord Valve, Ned Carlson
and Jim
McShane have encountered this phenomenon. You'd think they'd
have seen a
*lot* of NOS tubes over the years.

Cheers,
Fred
--

I burn *everything* in, current or NOS. I have to. The new
ones need to
have the cathodes cooked for awhile before they start emitting
as
much as they are capable of. Best way for this is to crank the
plate
voltage down and pull lots of current through 'em. About 60 mA
at
350V is good for 6L6s. If you check emission before and after,
you'll see about a 10-20% increase. The NOS stuff gets the same
treatment, but I run those at full voltage (~450 to 470) and
about 40
mA Ip. It's been a long time since I actually did any really
extensive
before/after testing on NOS power tubes, since the dudes who buy
'em from me are more concerned with them not croaking on tour
than with any hifalutin' specs. I juice 'em up nice and hot and
whack
the crap out of 'em with a nutdriver handle; if they don't spit
fire, I ship
'em. ;-) BTW, if you saw the Allman Brothers on Jay Leno a few
days ago, you heard a set of mine. I also built the amp you
heard
'em in. That tall amp Derek Trucks was playing through is the
one I'm talking about. (If you want the dope on it, run my
e-mail
address on Google groups and use "Super Six" for keywords.)

I just tried looking up the RDH4 on what it says about
burning in tubes which have never been used, and I couldn't
see too much.

But I recall from someplace that the tube should be pre "cooked"
48 hours with the heaters left running, with the cathode tied to
one side of the
6.3v,
and the all the other electrodes tied together, and to the other
side of the 6.3v.
This makes the cathode "ready for service",
and after this is done the tube is said to last longer.
Then the tube can be left running with some applied voltage and
current.

Anyone else aware of pre-cooking the tubes?

Many makers pre-used the tubes somehow, to avoid sending duds to
ppl; the military were not impressed by tubes which didn't work
when plugged in.

Patrick Turner.





Lord Valve
Tone Chaperone

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
QSC amps, RNC compressors, lots of other good stuff!

Partial Client List: * Derek Trucks/Allman Brothers Band *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* John Hall * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * The Right Half of AGA * Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at
303-778-1156

VISA - MASTERCARD - PAYPAL

Philo T. Farnsworth sez, "Vacuum tubes kick major ass.
Be a MAN...and buy some TODAY!"

But I recall from someplace that the tube should be pre "cooked"
48 hours with the heaters left running, with the cathode tied to one side of the
6.3v,
and the all the other electrodes tied together, and to the other side of the 6.3v.
This makes the cathode "ready for service",
and after this is done the tube is said to last longer.
Then the tube can be left running with some applied voltage and current.

Anyone else aware of pre-cooking the tubes?



Isn't that pretty much what tube manufactureres do when making tubes?
Heard that the
process calls for running the tube at double heater voltage for some
period of time
just before the vacuum pump finishes off the vacuum, then tube is sealed
and the
getter flashed. And hte getter mops up any residual gas.

"Patrick Turner" wrote in message
...

I just tried looking up the RDH4 on what it says about
burning in tubes which have never been used, and I couldn't
see too much.

Funny, I was reading this last night ......

RDH4, P3: "During the working life of the valve, its emission usually
increases over the early period, reaches a maximum at an age that varies
from valve to valve, and from one manufacturer to another, then begins to
fall. The user does not generally suffer any detriment until the emission
is insufficient to provide peak currents without distortion".

No mention of an actual burning-in process that I can recall, though.

Shiva wrote:
[...]


Hey, i have no shame - i go for the most cliche 60' wikid' far-out stuff -
13th floor elevators was what i was listenin' to as i was reading your post
(check it at at http://elysiansound.com/Earthquake.wma ). You've got to
love erickson's looniness lyrics... And if not, there's always that weird
jug b-bu-bu-b guy....

Finally got to listen to this, Linux doesn't seem to have a codec for
wma, and I refuse to use MediaSpyware... fortunately WinAmp knew what to
do with it.

Whoa, weird! But I like it. Pretty progressive for the '60s.

Here's one for you (and anyone else who likes weird crazy stuff). It's
kinda like West Coast "Revolution 9" or maybe Frank Zappa on 'Cid. From
Jefferson Airplane's "After Bathing at Baxter's" (1967, sort of "The
Dark Side of Surrealistic Pillow")

http://www3.telus.net/dogstarmusic/o...ll_package.mp3

It'll just be up for a couple days.

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+