OK, so when I asked about the bias setting on the Lumleys, Keith suggested
that the owner should be running Svets in there, as did several others, so I
went looking for some sources and prices. Watford Valves have some " Cryo -
Treated " Svet 6550C's for a couple of quid more than the 'standard' types.
See

http://www.watfordvalves.com/products.asp?id=10

This is a new one on me. Has anyone tried them ? Is there really any sound
or performance improvement from them ? Or have they maybe been cooled in a
big vat of the snake oil that everyone on here is so fond of talking about ?

Arfa

"Arfa Daily" wrote in message
...
OK, so when I asked about the bias setting on the Lumleys, Keith suggested
that the owner should be running Svets in there, as did several others, so
I went looking for some sources and prices. Watford Valves have some "
Cryo - Treated " Svet 6550C's for a couple of quid more than the
'standard' types. See

http://www.watfordvalves.com/products.asp?id=10

This is a new one on me. Has anyone tried them ? Is there really any sound
or performance improvement from them ? Or have they maybe been cooled in a
big vat of the snake oil that everyone on here is so fond of talking about
?

Arfa


This is an interesting one - another example of 'belief mechanisms' in
operation, but one where I *don't believe* it works. I don't *know* because
I haven't tried them myself, I've no intention of trying them and, worse
yet, I wouldn't *believe* anybody who did try them and said it did make a
difference!!

From what little Physics I do remember, I thought it was quite the opposite
of "At very cold temperatures (below -312°F), the molecules will align in a
more uniform, compact structure through the removal of kinetic energy." - I
thought the only way molecules could move in solid objects was if you
*heated* them up!
(Which is why blacksmiths ring the anvil when bashing red-hot metal about -
to 'jiggle' the molecules!)

Also, FWIW, if someone flogged me 'Cryo' valves I wouldn't even *believe*
they had been so treated anyway - how many fridges go down to -312°F...???
(Oh, OK - most valve dealers have got a cryo plant out in the back somewhere
then?)

(WTF is "CYROGENTIC" [sic] anyway - a proprietory name or one which
*implies* the real thing without being the real thing - like 'Mapleen
Syrup'....?? :-)

In article , Keith G
wrote:


From what little Physics I do remember, I thought it was quite the
opposite of "At very cold temperatures (below -312°F), the molecules
will align in a more uniform, compact structure through the removal of
kinetic energy." - I thought the only way molecules could move in solid
objects was if you *heated* them up! (Which is why blacksmiths ring the
anvil when bashing red-hot metal about - to 'jiggle' the molecules!)

In essence, you are correct and the quote is either incorrect or
misleading. :-)

If you wish materials to 'crystallise' then in general you may find it
useful to cool them slowly *through the range around their melting or
softening point*. I'd suspect that the materials used for the electrodes in
'valves' would be well below this at normal room temperature. Hence it
isn't clear cooling them to very low temperatures will do what is claimed.

Hard to see that if will affect the 'structure' of the vacuum, either...
:-)

Hence IIUC you'd have to first heat the valve to the point where the
materials were starting to melt, then slowly cool it *if* you wanted any
serious recrystallisation. But simply using it and then allowing it to cool
to room temperature would probably do much the same.

Also, FWIW, if someone flogged me 'Cryo' valves I wouldn't even
*believe* they had been so treated anyway - how many fridges go down to
-312°F...??? (Oh, OK - most valve dealers have got a cryo plant out in
the back somewhere then?)

I'm trying to work out what "-312 deg F' actually means as a real
temperature... :-) I'd thought that science and engineering moved on to
Kelvins some decades ago. Certainly, I stopped even thinking with F units
many years ago. Do they charge in pounds, shillings, and pence? :-)

Sounds to me like they just dunk the things in a bucket of liquid nitrogen
(77K). You can buy that by the bucketfull from your friendly local 'liquid
air' supplier. (Someone like BOC, Air Liquide, or a local uni)

(WTF is "CYROGENTIC" [sic] anyway - a proprietory name or one which
*implies* the real thing without being the real thing - like 'Mapleen
Syrup'....?? :-)

As distinct from Potcheen Syrup... :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

"Arfa Daily" wrote in message
...
OK, so when I asked about the bias setting on the Lumleys, Keith suggested
that the owner should be running Svets in there, as did several others, so
I went looking for some sources and prices. Watford Valves have some "
Cryo - Treated " Svet 6550C's for a couple of quid more than the
'standard' types. See

http://www.watfordvalves.com/products.asp?id=10

This is a new one on me. Has anyone tried them ? Is there really any sound
or performance improvement from them ? Or have they maybe been cooled in a
big vat of the snake oil that everyone on here is so fond of talking about
?

Arfa


My guess is you'd be better spending the extra on upgrading circuit
components but I have never actually tried those cryogenically treated
valves. I'll try and find my notes but I remember changing psu diodes over
to the faster UF5408 & UF4007. The 6550 cathodes now stand on 1 ohm w/w for
metering, several other changes like reduced global f/b and changes to both
the driver and input boards but as I say I'll try and find my original
notes. That was all of 10 years ago...

Mike

"Jim Lesurf" wrote in message
...
In article , Keith G
wrote:


From what little Physics I do remember, I thought it was quite the
opposite of "At very cold temperatures (below -312°F), the molecules
will align in a more uniform, compact structure through the removal of
kinetic energy." - I thought the only way molecules could move in solid
objects was if you *heated* them up! (Which is why blacksmiths ring the
anvil when bashing red-hot metal about - to 'jiggle' the molecules!)

In essence, you are correct and the quote is either incorrect or
misleading. :-)

If you wish materials to 'crystallise' then in general you may find it
useful to cool them slowly *through the range around their melting or
softening point*.


Yes, I'd call that 'annealing'....


I'd suspect that the materials used for the electrodes in
'valves' would be well below this at normal room temperature. Hence it
isn't clear cooling them to very low temperatures will do what is claimed.


Exactly!!


Hard to see that if will affect the 'structure' of the vacuum, either...
:-)

Hence IIUC you'd have to first heat the valve to the point where the
materials were starting to melt, then slowly cool it *if* you wanted any
serious recrystallisation. But simply using it and then allowing it to
cool
to room temperature would probably do much the same.


You could always heat them up and hold them at an angle of 71 deg pointing
North and then hit them smartly wiv a hammer - it would make them very
slightly 'magnetic'....

:-)

Keith G wrote

From what little Physics I do remember, I thought it was quite the
opposite of "At very cold temperatures (below -312°F), the molecules
will align in a more uniform, compact structure through the removal of
kinetic energy." - I thought the only way molecules could move in solid
objects was if you *heated* them up! (Which is why blacksmiths ring the
anvil when bashing red-hot metal about - to 'jiggle' the molecules!)

In essence, you are correct and the quote is either incorrect or
misleading. :-)

If you wish materials to 'crystallise' then in general you may find it
useful to cool them slowly *through the range around their melting or
softening point*.


Yes, I'd call that 'annealing'....


I'd suspect that the materials used for the electrodes in
'valves' would be well below this at normal room temperature. Hence it
isn't clear cooling them to very low temperatures will do what is claimed.


Exactly!!


Hard to see that if will affect the 'structure' of the vacuum, either...
:-)

Hence IIUC you'd have to first heat the valve to the point where the
materials were starting to melt, then slowly cool it *if* you wanted any
serious recrystallisation. But simply using it and then allowing it to cool
to room temperature would probably do much the same.


You could always heat them up and hold them at an angle of 71 deg pointing
North and then hit them smartly wiv a hammer - it would make them very
slightly 'magnetic'....

Worked with Miller and some Lucas dynamos, sometimes, reputedly :-)

It must take a while for the heat to escape. How do they know when it's done?

How do they avoid cracking the glass or the metal, or weakening the joints
between dissimilar materials?

There seems to be common in the claims something about relieving "internal
stresses", whatever that means. It may be plausible...I forget if I ever knew
anything about metal at low temperatures...presumably crystals can be unformed
by making them either very big or very small.

Perhaps it is the equivalent of work hardening, where discontinuities are
squeezed out of crystal boundaries?

Perhaps that then effects the way that perveance-enhancing constituents of the
cathode alloy migrate to the surface?

cheers, Ian

"Ian Iveson" wrote


You could always heat them up and hold them at an angle of 71 deg
pointing North and then hit them smartly wiv a hammer - it would make
them very slightly 'magnetic'....

Worked with Miller and some Lucas dynamos, sometimes, reputedly :-)

It must take a while for the heat to escape. How do they know when it's
done?

How do they avoid cracking the glass or the metal, or weakening the joints
between dissimilar materials?

There seems to be common in the claims something about relieving "internal
stresses", whatever that means. It may be plausible...I forget if I ever
knew anything about metal at low temperatures...presumably crystals can be
unformed by making them either very big or very small.

Perhaps it is the equivalent of work hardening, where discontinuities are
squeezed out of crystal boundaries?

Perhaps that then effects the way that perveance-enhancing constituents of
the cathode alloy migrate to the surface?


I'm not qualified to comment, but I will say that, in general, I *believe*
the opposite - the appropriate application of heat allows change in solid
objects, the application of extreme cold prevents it.....

"Keith G" wrote in message
...

"Ian Iveson" wrote


You could always heat them up and hold them at an angle of 71 deg pointing
North and then hit them smartly wiv a hammer - it would make them very
slightly 'magnetic'....

Worked with Miller and some Lucas dynamos, sometimes, reputedly :-)

It must take a while for the heat to escape. How do they know when it's done?

How do they avoid cracking the glass or the metal, or weakening the joints
between dissimilar materials?

There seems to be common in the claims something about relieving "internal
stresses", whatever that means. It may be plausible...I forget if I ever knew
anything about metal at low temperatures...presumably crystals can be
unformed by making them either very big or very small.

Perhaps it is the equivalent of work hardening, where discontinuities are
squeezed out of crystal boundaries?

Perhaps that then effects the way that perveance-enhancing constituents of
the cathode alloy migrate to the surface?


I'm not qualified to comment, but I will say that, in general, I *believe* the
opposite - the appropriate application of heat allows change in solid objects,
the application of extreme cold prevents it.....


http://www.frozensolid.co.uk/science.htm

for example.

Like other forms of cold working, it drives out the dislocations from the
structure. Seems also to encourage the formation of carbide in iron, and who
knows what other structural changes in other metals and alloys, similar to those
caused by pressure perhaps.

cheers, Ian

"Arfa Daily" wrote in message

OK, so when I asked about the bias setting on the
Lumleys, Keith suggested that the owner should be running
Svets in there, as did several others, so I went looking
for some sources and prices. Watford Valves have some "
Cryo - Treated " Svet 6550C's for a couple of quid more
than the 'standard' types. See

http://www.watfordvalves.com/products.asp?id=10

What was it that P.T. Barnum said?

This is a new one on me.

Cryogenic treatment of just about anything, followed by pseudoscientific
claims for improved performance is decades old.

Has anyone tried them ?

Admitting this is IMO like admitting to being a born sucker.

Is there really any sound or performance improvement from them ?

One that is readily demonstrable in a sighted evaluation, of course.

Or have they maybe been cooled in a big vat of the snake
oil that everyone on here is so fond of talking about ?

Very good, grasshopper. You have learned well! ;-)

"Arny Krueger" wrote in message
...
"Arfa Daily" wrote in message

OK, so when I asked about the bias setting on the
Lumleys, Keith suggested that the owner should be running
Svets in there, as did several others, so I went looking
for some sources and prices. Watford Valves have some "
Cryo - Treated " Svet 6550C's for a couple of quid more
than the 'standard' types. See

http://www.watfordvalves.com/products.asp?id=10

What was it that P.T. Barnum said?

This is a new one on me.


Cryogenic treatment of just about anything, followed by pseudoscientific
claims for improved performance is decades old.


No, honestly Arny. I've been around in the electronic service business for
35 years, and cut my teeth on valves as an apprentice. I still service a lot
of valve gear now. In all of those years, I have never heard of anyone doing
this to a valve, and claiming that it alters the characteristics in any way.
Having now looked, there does seem to be a lot of people on the web
providing the service, and making all sorts of claims about it, but from a
service engineers point of view, I've never before heard of it, or seen any
articles in the trade press about it.

Has anyone tried them ?

Admitting this is IMO like admitting to being a born sucker.

I'm inclined to agree, but I was just interested to see if anyone actually
did come back on this one with any claims - at the risk of starting another
" I can hear the difference between bell wire and electricity board cable "
debate. It just might have been that someone had some proper measurements
that they'd done, but it would be hard to carry out such measurements, as
you would have to do them on a before and after basis on the same valve.

Is there really any sound or performance improvement from them ?

One that is readily demonstrable in a sighted evaluation, of course.

Again, I was just looking for an opinion from anyone that might have been
tempted to have tried them. I certainly wasn't about to recommend them to my
customer, no matter what anyone said, but if there had have been anyone come
back and say anything positive about them, then I might myself have been
tempted to get a couple ( no matter how much of a mug you or anyone else
might think that that makes me ), purely from a research interest point of
view.

Or have they maybe been cooled in a big vat of the snake
oil that everyone on here is so fond of talking about ?

Very good, grasshopper. You have learned well! ;-)


Glad I've pleased you ...

Arfa