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Andre Jute Andre Jute is offline
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If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?

Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.

Andre Jute
A little inaccuracy sometimes saves tons of explanation. --H.H.Munro
("Saki")(1870-1916)

Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

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John Byrns John Byrns is offline
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In article .com,
Andre Jute wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?


How about a nice indirectly heated power triode with an anode
dissipation limit of 50 Watts, transconductance of 10 mmhos, and a mu of
5.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
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RapidRonnie RapidRonnie is offline
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On Aug 13, 10:42 am, John Byrns wrote:
In article .com,
Andre Jute wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?


How about a nice indirectly heated power triode with an anode
dissipation limit of 50 Watts, transconductance of 10 mmhos, and a mu of
5.



You want a triode built around a KT88 plate structure and envelope.

I'd say a triode also, but with a direct filament, or better yet two
for series or parallel operation, with a somewhat higher plate rating
and a little higher mu. Something in between a 300B and a 211.

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maxhifi maxhifi is offline
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Brand new Sylvania 8417's for $5 each


"Andre Jute" wrote in message
oups.com...
If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?

Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.

Andre Jute
A little inaccuracy sometimes saves tons of explanation. --H.H.Munro
("Saki")(1870-1916)

Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review



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Chris Hornbeck Chris Hornbeck is offline
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On Tue, 14 Aug 2007 02:51:59 GMT, "maxhifi" wrote:

Brand new Sylvania 8417's for $5 each


No problemo. I've got a catalog somewhere around here
with matched pairs of Genelex KT88's for $12.00. Just
jump in Mister Peabody's WABAC machine and grab a couple
of whatever ails ya.

And, would you grab me a coupla KT66's, just for
souvenirs, doncha know?

Thanks, as always,

Chris Hornbeck
"It's just this little Chromium Switch.
You people are SO superstitious."


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Chris Hornbeck Chris Hornbeck is offline
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On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute
wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?

Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.


A pretty broad, but still very interesting question. Small
signal and medium signal tubes are already pretty great, so
the hunt must go to output tubes.

Linearity and long service life favor a pretty primitive
tube family (1000 volts, thoriated tungsten filaments, the
whole 1930's shtick) but there is one exception. The WE
type 300 managed, by sheer will power, to run linearly and
well at 500 volts on oxide-coated filaments.

So, my fantasy tube would be a type 300, but

WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do?

Jeez.




I'm better now. Thanks for the opportunity to vent.
Sorry... sorry...

And, thanks as always,

Chris Hornbeck
"It's just this little Chromium Switch.
You people are SO superstitious."
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maxhifi maxhifi is offline
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"Chris Hornbeck" wrote in message
...
On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute
wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?

Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.


A pretty broad, but still very interesting question. Small
signal and medium signal tubes are already pretty great, so
the hunt must go to output tubes.

Linearity and long service life favor a pretty primitive
tube family (1000 volts, thoriated tungsten filaments, the
whole 1930's shtick) but there is one exception. The WE
type 300 managed, by sheer will power, to run linearly and
well at 500 volts on oxide-coated filaments.

So, my fantasy tube would be a type 300, but

WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do?

Jeez.


How about a matched pair of 6L6GC's in a compactron envelope, made large to
resemble a 300B... or better yet a matched pair of 6L6's, and a 6SL7 in one
envelope, with a new, 20 pin base. Guitar amps would never be cheaper to
make, and you'd only have one tube to change (ok maybe it would need another
12ax7 or something, but could have a one tube power amp!)

Or technically speaking, if someone could make a very linear beam power
tube, with a 50W anode dissapation limit, which has such a high gain it only
requires 3V of drive to achieve full power, but stable, and not prone to
'meltdown'. Then you could heap on the local NFB and have a nice low output
impedance, without worrying about your driver having to swing a huge
voltage. (8417 was the best in this category, so far as I know!)

Or... a linear triode with a huge flat cathode, large enough to handle
several amps, designed especially for OTL amplifiers. This could be in a new
envelope style, with a specially designed base. No need to make it octal and
glass, or to look anything like the tubes we're used to.

How about a microscopic sized planar tube, made on a nano scale, with some
new method of etching the grids photographically, rather than winding them.
It could be in a little metal case, like a crystal. Maybe even make it
surface mount, and overbuilt and derated so it would never need to be
replaced. It could be attached to a heat sink like a transistor if you
needed more power, and for the really powerful ones, the anode could be the
inside of the case. Then you could buy a cell phone with a tube output stage



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Chris Hornbeck Chris Hornbeck is offline
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On Tue, 14 Aug 2007 04:18:28 GMT, "maxhifi" wrote:

How about a matched pair of 6L6GC's in a compactron envelope, made large to
resemble a 300B... or better yet a matched pair of 6L6's, and a 6SL7 in one
envelope, with a new, 20 pin base. Guitar amps would never be cheaper to
make, and you'd only have one tube to change (ok maybe it would need another
12ax7 or something, but could have a one tube power amp!)


Could be done, but nobody would buy 'em. Everybody's already
got guitar amps; nobody has a personal MIG fighter plane; like
that. But, Arf!


Or technically speaking, if someone could make a very linear beam power
tube, with a 50W anode dissapation limit, which has such a high gain it only
requires 3V of drive to achieve full power, but stable, and not prone to
'meltdown'. Then you could heap on the local NFB and have a nice low output
impedance, without worrying about your driver having to swing a huge
voltage. (8417 was the best in this category, so far as I know!)


Transconductance is the natural enemy of cathode poisoning. These
tend to devolve into issues of material purity - not a good subject
to broach "in these days of modern times". Vacuum valve manufacture
is no less complex now than it was in the Kennedy era; the difference
now is that nobody cares.


Or... a linear triode with a huge flat cathode, large enough to handle
several amps, designed especially for OTL amplifiers. This could be in a new
envelope style, with a specially designed base. No need to make it octal and
glass, or to look anything like the tubes we're used to.


That's a Russian type 6336. Get 'em while they're hot. No magic of
design can do more than that within design constraints.


How about a microscopic sized planar tube, made on a nano scale, with some
new method of etching the grids photographically, rather than winding them.
It could be in a little metal case, like a crystal. Maybe even make it
surface mount, and overbuilt and derated so it would never need to be
replaced. It could be attached to a heat sink like a transistor if you
needed more power, and for the really powerful ones, the anode could be the
inside of the case. Then you could buy a cell phone with a tube output stage


Stranger than fiction, something like this might actually happen. Hot
cathode emission has only been used in easily-visible-size valves to
date, but maybe that's just a failure of imagination (and
manufacturing capability, a temporary thing).

There are technical advantages to vacuum valves over roughly similar
silicon wafer valves (parasitic capacitance, for example), so the
future is still undefined.


And, let's all give Thanks for that. I think. No, I hope.
No, I wish. No, I'm really glad.

But anyway, thanks, as always,

Chris Hornbeck
"It's just this little Chromium Switch.
You people are SO superstitious."
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Could be done, but nobody would buy 'em. Everybody's already
got guitar amps; nobody has a personal MIG fighter plane; like
that. But, Arf!


Never know, if one of the big amp companies could get Guitar Player to
convince people it's a good idea, and then get some big names behind the amp
line, they could sell some. There's no shortage of baby boomers who want to
play the blues. All the same, I agree, it's likely cheaper to stick with
what's already there. Plus, I admit, it's kind of a boring fantasy tube,
because it dosen't really improve on anything, just re-package it, and
possibly make it cheaper, although less flexible.

Transconductance is the natural enemy of cathode poisoning. These
tend to devolve into issues of material purity - not a good subject
to broach "in these days of modern times". Vacuum valve manufacture
is no less complex now than it was in the Kennedy era; the difference
now is that nobody cares.


Yes, but that's what makes it a fantasy tube... it dosen't break any laws of
physics, but similar to other fantasies, such as having a fulfilling
marriage to a supermodel, it's not meant to be. All the same, tubes like
8417 and 7591A came close, and if developed further, could result in
something. For example, could frame grid technology a la 6DJ8 be applied to
an output tube?

That's a Russian type 6336. Get 'em while they're hot. No magic of
design can do more than that within design constraints.


I think the 6336 is a US tube - a super regulator dual triode which looks
like a KT88 - you mean the 6C33 or whatever it's called. I saw some of those
recently - really impressive and strange looking beasts! All the same, they
were not originally designed as OTL output tubes, and I'm sure they could be
improved upon if it was an application specific design, from the ground up.
My guess is if you gave a several million dollar grant to say, atma-sphere,
and, say, JJ, or svetlana to work together to come up with the ultimate OTL
tube, something better than the 6C33 or 6AS7 would result.

Stranger than fiction, something like this might actually happen. Hot
cathode emission has only been used in easily-visible-size valves to
date, but maybe that's just a failure of imagination (and
manufacturing capability, a temporary thing).


I wonder if there really is a technical reason for this. Is there a physical
limit to how small a hot cathode tube can be, and still work? I am sure
there would be huge challenges to overcome, but if solved, it could be
interesting.


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Peter Wieck Peter Wieck is offline
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On Aug 13, 11:23 pm, Chris Hornbeck
wrote:
On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute
wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?


Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.


A pretty broad, but still very interesting question. Small
signal and medium signal tubes are already pretty great, so
the hunt must go to output tubes.

Linearity and long service life favor a pretty primitive
tube family (1000 volts, thoriated tungsten filaments, the
whole 1930's shtick) but there is one exception. The WE
type 300 managed, by sheer will power, to run linearly and
well at 500 volts on oxide-coated filaments.

So, my fantasy tube would be a type 300, but

WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do?

Jeez.

I'm better now. Thanks for the opportunity to vent.
Sorry... sorry...

And, thanks as always,

Chris Hornbeck
"It's just this little Chromium Switch.
You people are SO superstitious."


Oh, I dunno... The KT88/6550 and KT90 are pretty good tubes given that
I have no predilections towards SE devices. My fantasy tube would be
new-production small-signal tubes along the lines of the Sylvania
Mil.Spec. series with the 5751 being the best of that. Very low noise,
low microphonics, great longevity.... So, make of that quality, but
include the various 6XX and 12XX tubes, miniature and octal as needed.

Of, course were I to be having a Jutean Fantasy, I would extend that
wish-for-quality to extend to power-tubes as well.

Never happen.

Peter Wieck
Wyncote, PA



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tubegarden tubegarden is offline
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Hi RATs!

It probably already exists. My fantasy is I will get it into a
friendly circuit before I pop my filament.

I put new JJ E88CC in the first stage of Ella and the EL34 sounds
really great.

Happy Ears!
Al


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Andre Jute Andre Jute is offline
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tubegarden wrote:

Hi RATs!

It probably already exists.


It is human nature to think the glass is half-empty when in fact it is
two-thirds full. -- Andre Jute

My fantasy is I will get it into a
friendly circuit before I pop my filament.

I put new JJ E88CC in the first stage of Ella and the EL34 sounds
really great.

Happy Ears!
Al


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Andre Jute Andre Jute is offline
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Andre Jute wrote:

If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would
you ask for?

Clearly, whatever you specify must not breach the laws of physics,
such as asking for a tube giving a hundred watts in Class A for a year
on a single AA battery.


I deliberately didn't specify my own idea to start with so that
everyone else could have all the court to shoot from. But it is
amazing how alike we all think, at least as long as we stay inside the
envelope; in fact it will look like I took my idea from John, from
Ronnie, from Chris and from Max!

My idea is a twin triode in an octal base glass tube the shape of and
no larger than a 300B, working off a real life (not max) B+ of 385V
and requiring no more than 60V of signal for full output, which should
be in the order of 10W per side (real output at everyday parameters,
not theoretical output at Pdmax; a WE300B is effectively a 6W SE tube
in real life, not the 10W American ponycar amp makers claim).
Indirectly heated filaments might be nice but I don't consider them as
essential as John does; DH fils have never bothered me much. I don't
care how hot the tube gets if the longevity is reasonable. It seems to
me that the 300B/845/211, that entire lot, are tubes whose performance
is depressed in favour of longevity; I have WE300B getting on for 20K
hours, at least, an entirely unreasonable life expectancy, in effect
indestructable in conservative designs.

Two tubes in the same envelope so it can be PSE or PP. Octal for cost.
10W per side so that 20W is easily achieved in PSE or more in PP up to
much more with variation among output classes. 385V is chosen for
component cost; it fits into the standard cap for 230V mains, so the
any iso-transformer will do, and the caps are cheap too. 60V signal is
easily achieved with a single or at most two stages of voltage
amplification.

I'd also specify a second tube as a driver: two 417A in the same
envelope, which can be bigger than the child's thumb of the present
417A, say up to 6SN7 size. (Actually, I'd ask for two 437A in the same
envelope, and settle for the two 417A if the man said 437A are
impossible. A 417A is good up to 24mA and has a mu of over 40; a 437A
is a 417A on a lifelong diet of steroids.) The reason for asking for
20mA and over is because that is what is necessary on a driver to
overcome Miller in PSE 300B or single 845, which have approximately
the same parameters I specify above. Or, if I can't have any of that,
how about 4x 6SN7 in one envelope, or 2x 6SL7 + 2x 6SN7? But these are
just convenience matters (except for the unobtainable 437A); as Chris
says, small signal and driver tubes are probably a done deal, at a
peak of perfection.

And, since I would have the guy pinned down, still trying to close his
mouth, I'd impress on him the necessity of a new rectifier, twin GZ37
in one tube, i.e. a complete one-tube high voltage high current bridge
rectifier). The reason I don't choose the venerated GZ34 is that the
-37 is a better rectifier in every respect and anyway its size and
shape match the 300B bulb I've already specified above. All that heat
may need the bigger tube too than the GZ34.

The reason for asking for a kilovolt tube bridge rectifier is many a
slip twixt the cup and the lip: the new tubes may turn out to be
rubbish and then we shall all want to go back to 845...

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

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John Byrns John Byrns is offline
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In article om,
Andre Jute wrote:

And, since I would have the guy pinned down, still trying to close his
mouth, I'd impress on him the necessity of a new rectifier, twin GZ37
in one tube, i.e. a complete one-tube high voltage high current bridge
rectifier). The reason I don't choose the venerated GZ34 is that the
-37 is a better rectifier in every respect and anyway its size and
shape match the 300B bulb I've already specified above. All that heat
may need the bigger tube too than the GZ34.


Wouldn't it take something more like a triple GZ37 to make "a complete
one-tube high voltage high current bridge rectifier"? At least three
independent cathodes would be required, along with three rectifier
heater windings on the Power Transformer.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
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maxhifi maxhifi is offline
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Wouldn't it take something more like a triple GZ37 to make "a complete
one-tube high voltage high current bridge rectifier"?


I think he means one complete GZ37, and then another complete one with
independent cathode connections.

At least three
independent cathodes would be required, along with three rectifier
heater windings on the Power Transformer.


Not if the heater/cathode insulation is up to the task. If the EZ81 can
handle it, so can this super tube! Make it a 6.3V heater, too.




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Peter Wieck Peter Wieck is offline
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William of Occam suggests that it is dangerous to multiply entities
needlessly. So, in striving for the "Perfect Tube", it would be my
contention that overly complex tubes, and/or tubes required to serve
too many purposes become dangerously complex with a logarithmic
propensity towards error/failure.

I deliberately didn't specify my own idea to start with so that
everyone else could have all the court to shoot from. But it is
amazing how alike we all think, at least as long as we stay inside the
envelope; in fact it will look like I took my idea from John, from
Ronnie, from Chris and from Max!

My idea is a twin triode in an octal base glass tube the shape of and
no larger than a 300B, working off a real life (not max) B+ of 385V
and requiring no more than 60V of signal for full output, which should
be in the order of 10W per side (real output at everyday parameters,
not theoretical output at Pdmax; a WE300B is effectively a 6W SE tube
in real life, not the 10W American ponycar amp makers claim).
Indirectly heated filaments might be nice but I don't consider them as
essential as John does; DH fils have never bothered me much. I don't
care how hot the tube gets if the longevity is reasonable. It seems to
me that the 300B/845/211, that entire lot, are tubes whose performance
is depressed in favour of longevity; I have WE300B getting on for 20K
hours, at least, an entirely unreasonable life expectancy, in effect
indestructable in conservative designs.


A 300B on steroids may be a good idea, save that it leads to the
necessary admission that SE designs have inherent limitations in
headroom that could be solved with a "Bigger Tube".... this leads to
the inevitable Americanism: When all else fails, get a bigger hammer.
The last 80 years of tube design have generally shown that after flea-
power comes PP, and that PP systems may be (to use Mr. Turner's word)
"blameless" with good design.

Two tubes in the same envelope so it can be PSE or PP. Octal for cost.
10W per side so that 20W is easily achieved in PSE or more in PP up to
much more with variation among output classes. 385V is chosen for
component cost; it fits into the standard cap for 230V mains, so the
any iso-transformer will do, and the caps are cheap too. 60V signal is
easily achieved with a single or at most two stages of voltage
amplification.


Now, here is where the laws of physics-on-the-cheap get nudged. Heat
dissipation is a function of design, envelope size (exposure) and
other mechanical factors. This would necessarily be a fairly large
tube, on the order of some of the more significant transmitter tubes
and therefore something of a real-estate hog. Furthermore, that sort
of power-handling would also require the perfect socket with perfect
contact surfaces. So far, though, well within good science and (quite-
costly) available technology. But price would definitely be an
object.

And again, putting both in the same envelope does considerably
multiply entities, especially in a power-tube. Advantages: the
presumption that both sections age equally and together.
Disadvantages: The entire tube becomes useless should that not be so.

I'd also specify a second tube as a driver: two 417A in the same
envelope, which can be bigger than the child's thumb of the present
417A, say up to 6SN7 size. (Actually, I'd ask for two 437A in the same
envelope, and settle for the two 417A if the man said 437A are
impossible. A 417A is good up to 24mA and has a mu of over 40; a 437A
is a 417A on a lifelong diet of steroids.) The reason for asking for
20mA and over is because that is what is necessary on a driver to
overcome Miller in PSE 300B or single 845, which have approximately
the same parameters I specify above. Or, if I can't have any of that,
how about 4x 6SN7 in one envelope, or 2x 6SL7 + 2x 6SN7? But these are
just convenience matters (except for the unobtainable 437A); as Chris
says, small signal and driver tubes are probably a done deal, at a
peak of perfection.

And, since I would have the guy pinned down, still trying to close his
mouth, I'd impress on him the necessity of a new rectifier, twin GZ37
in one tube, i.e. a complete one-tube high voltage high current bridge
rectifier). The reason I don't choose the venerated GZ34 is that the
-37 is a better rectifier in every respect and anyway its size and
shape match the 300B bulb I've already specified above. All that heat
may need the bigger tube too than the GZ34.

The reason for asking for a kilovolt tube bridge rectifier is many a
slip twixt the cup and the lip: the new tubes may turn out to be
rubbish and then we shall all want to go back to 845...


Mpfffff.... OK.... being a crude American, a heavy duty rectifier is
hard enough these days, putting two of them in the same envelope gets
quite close to the physical limitations of the beast... and three (or
more) to make the full bridge becomes needlessly complex.

As to the 417a et.al., I would take a lesson from the venerable7199, a
tube that brackets the extremes of excellence and failure, with the
general propensity towards the latter end of the spectrum. In the
words of George Santyana: "Those who do not remember the past are
condemned to repeat it." I happen to very much like the 7199, when I
have a dozen available to find two or three good ones. But for that
reason, I am staying away from it and that general philosophy with my
homebrew. I have my stock of very good 7199s, but it took me some
years and a few dozen examples to find my six working pairs and six
spares.

I would strive for refinement of existing tube designs, or as the KT90
is an evolutionary improvement to the KT88, strive in those
directions. Tube design has been "perfect" for about 40 years now in
terms of genuine and actual new designs or approaches. Packaging
differences lead to a false sense of simplicity with greater
complexity in the design with little potential for real improvement.
Much as chips offer the same sorts of pitfalls and pratfalls as
compared to discrete components... Lest anyone think I am being a
luddite, not hardly. Cell Phones have the functional equivalent of a
trainload of discrete components, no argument there. But power
amplifiers are not cell phones and overly complicated multi-function
tubes are called Compactrons last I looked.

And, we must all remember, WE was an entity of the Bell System,
concerned with reliable telephone service, movie recording and sound
systems and other broad-brush applications where reliability and
simplicity and longevity and ease of service were driving factors with
'fidelity' being an almost accidental by-product. So their tubes were
to that end and adapted to home audio systems only as latter-day
adaptations. The bandwidth of a 1950s land line was no better than the
typical single-driver horn speaker, so not much was needed of the
electronics other than reliabilty. Similarly all but a very few movie
houses used a couple of massive horn speakers (woofer & tweeter), with
not much expected there either other than within the voice spectrum.

Give me the functional equivalent of a Sylvania Mil.Spec. 5751 at all
levels of the tube spectrum, and I will be a very happy camper. In
general, I am easily pleased. It need only sound good. Looks, cost,
and yiches notwithstanding. That tube is a very fine combination of
price, function, ruggedness and longevity. Would they were all so...
THAT is my fantasy.

To each his own. This is a fantasy throughout, so we are all entitled
to our own without limit.

Peter Wieck
Wyncote, PA

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Andre Jute Andre Jute is offline
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On Aug 14, 4:43 pm, John Byrns wrote:
In article om,
Andre Jute wrote:

And, since I would have the guy pinned down, still trying to close his
mouth, I'd impress on him the necessity of a new rectifier, twin GZ37
in one tube, i.e. a complete one-tube high voltage high current bridge
rectifier). The reason I don't choose the venerated GZ34 is that the
-37 is a better rectifier in every respect and anyway its size and
shape match the 300B bulb I've already specified above. All that heat
may need the bigger tube too than the GZ34.


Wouldn't it take something more like a triple GZ37 to make "a complete
one-tube high voltage high current bridge rectifier"? At least three
independent cathodes would be required, along with three rectifier
heater windings on the Power Transformer.


Yes, you're right. This was pointed out to me by Mr Williamson, my
correspondence tube electronics tutor with whom I had been studying
Kondo's Ongaku, when I just naturally put four GZ37 on my first
kilovolt supply. But a decade and more has passed since then, and I
still use four full wave GZ37 per bridge (God bless Billington for
supply, and for 5R4GWY -- the ones with ceramic bowl base -- that
actually do the HV business unlike some probably Russian-made rubbish
I also had) and my trannies have four filament supplies... I just
forgot.

But even if we take up Max's idea, of a second GZ37 in the same
envelope with an independent filament for each plate, that's too many
connectors to fit into my other parameter of a standard octal base.
(Four plates and 6 filament/cathode connectors add up to 10.)

I'll have to amend that to a GZ37 with separate cathodes/fils per
plate separately brought out. Still, that's only two tubes for a
bridge, rather than three, so there's a saving of one tube, and other
convenience too. (Though, on the whole, I am not impressed with
crosstalk through the filaments, which once exercised the obsessives
on the Joenet. I remember mentioning it to Simon S, the British amp
and tranny designer, and he burst out laughing.)

Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/


Thanks for bringing Mr Williamson to my mind. I haven't thought of him
recently, and he deserves to be remembered for everything he taught
me.

Andre Jute
Now let us praise famous men -- Ecclesiastes

Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

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John Byrns John Byrns is offline
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In article .com,
Andre Jute wrote:

But even if we take up Max's idea, of a second GZ37 in the same
envelope with an independent filament for each plate, that's too many
connectors to fit into my other parameter of a standard octal base.
(Four plates and 6 filament/cathode connectors add up to 10.)


The triple cathode scheme I suggested requires only 7 pins, so it would
easily fit an octal socket, although the creepage distance might not be
enough for a kilovolt supply. Perhaps one of those ceramic bowl bases
like the 5R4GWY has, along with a ceramic socket, might make it workable.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
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Andre Jute Andre Jute is offline
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On Aug 16, 6:19 pm, Bret Ludwig wrote:
Don't say I said so, but as close as is going to exist to what Andrew
wants already does: it's a 3C33.


Spec sheet with curves here.

http://frank.yueksel.org/sheets31.html

Very nice indeed. Offered for sale elsewhere for USD75 each, doesn't
say how many the dealer has or what prospect of replacement... Sockets
by Johnson still in production, offered yet another place for USD45
each. Makes 845 look cheap. At these prices it may be worth trying a
little SE amp for those desperate for a new thrill. At least it is a
tube with a different, interesting shape.

Andre Jute

That same socket is what YOU want, except, you don't.

If you really wanted a tube rectifier-and if sound and not EMP
resistance is the goal, you really do not-what you want is not a
vacuum type but a xenon gas type. Refer to the GEC manual. The mercury
vapor type is also good if you are willing to put it in a cage and put
RF chokes in, but I doubt any tube plant will make them for you.

I would not bother making a new vacuum rectifier type for the simple
reason that if someone is hellbent on vacuum rectification they can
always use a strapped triode.



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Andre Jute Andre Jute is offline
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On Aug 14, 8:25 pm, John Byrns wrote:
In article .com,
Andre Jute wrote:

But even if we take up Max's idea, of a second GZ37 in the same
envelope with an independent filament for each plate, that's too many
connectors to fit into my other parameter of a standard octal base.
(Four plates and 6 filament/cathode connectors add up to 10.)


The triple cathode scheme I suggested requires only 7 pins, so it would
easily fit an octal socket, although the creepage distance might not be
enough for a kilovolt supply. Perhaps one of those ceramic bowl bases
like the 5R4GWY has, along with a ceramic socket, might make it workable.

Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/


Mmm. I had something in mind in which the rectifieers may serve as a
bridge, or be used separately, for instance as in my Modular Series
300B Lundahl where I merely fullwave rectified two separate lines. But
I think this rectifier idea of mine, a throwaway at the end, is the
most troublesome of all the ideas floated by anyone yet.

How high is an octal socket supposed to be rated? I used to have a
Tannoy amp that put 864V into an octal socket and I'm sure they
wouldn't have done so if the socket was not rated for it.

And, while we're on sockets, one of the reason I like the octal is
that it is reasonably well insulated from the top. A UX4 for a 300B or
a Jumbo 4-pin for an 845 is lethal when the tube is not in it.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review




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tubegarden tubegarden is offline
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I put new JJ E88CC in the first stage of Ella and the EL34 sounds
really great.


Happy Ears!


.... days later ... the new tubes are teaching the entire system and
room how to Play Music.

.... I may even become a better listener, if not more exciting typist.

The new IP connection tests at 2475m/750m. I would like to post videos
of how to treat tubes to a fun life ... but, at the speed I type, I
would be dead before I finish heater principles.

Anybody ready for video NG for empty heads on tube post
recreationistas?

Al


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